# [RFC] Stream Error Handling Improvements

- Thread: https://externals.io/message/129289
- Original archive: https://news-web.php.net/php.internals/129289
- Started by Jakub Zelenka on 2025-11-18T18:38:37+00:00
- Messages: 44
- RFC: Stream Error Handling Improvements (Implemented (PHP 8.6)) — https://externals.io/rfc/stream_errors.md
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---

## #129289 — Jakub Zelenka — 2025-11-18T18:38:37+00:00

URL: https://externals.io/message/129289#129289

Hello,

I would like to introduce a new stream error handling RFC that is part of
my stream evolution work (PHP Foundation project funded by Sovereign Tech
Fund) :

https://wiki.php.net/rfc/stream_errors

Kind regards,

Jakub

---

## #129290 — ignace nyamagana butera — 2025-11-18T19:33:44+00:00

URL: https://externals.io/message/129289#129290 · In reply to: #129289

> Hello,
>
> I would like to introduce a new stream error handling RFC that is part of
> my stream evolution work (PHP Foundation project funded by Sovereign Tech
> Fund) :
>
> https://wiki.php.net/rfc/stream_errors
>
> Kind regards,
>
> Jakub
>
> Hi Jakub,

This is a nice RFC. Since I use a lot of PHP streaming capabilities I am
looking forward to its voting outcome. Having said that, did you think,
instead adding more constants in the global namespace, of using Enum as an
alternative for error code. There is a precedent for that in the new URI
extension, This would
reduce the number of new constants added and perhaps make for a more modern
DX for the feature.
What do you think?

Best regards,
Ignace

---

## #129291 — Bob Weinand — 2025-11-19T05:14:18+00:00

URL: https://externals.io/message/129289#129291 · In reply to: #129289

Hey Jakub,


> Hello,
>
> I would like to introduce a new stream error handling RFC that is part 
> of my stream evolution work (PHP Foundation project funded by 
> Sovereign Tech Fund) :
>
> https://wiki.php.net/rfc/stream_errors
>
> Kind regards,
>
> Jakub


I super appreciate that you've tackled this. This has been a big wart in 
PHP's stream handling for a long time.


I have a couple questions:

Why have you chosen a big list of constants rather than enums?
I think we should push for enums where applicable, meaning enum 
StreamErrorMode, enum StreamErrorStore, enum StreamError.

You define what a terminal error is, but does it correlate to specific 
error codes? Like, is a given error code always terminal or not 
terminal? Or can some error codes sometimes be terminal or not terminal 
depending on context?
I've tried to look at the code, but I don't quite understand it, e.g. 
php_plain_files_rename: When chown or chmod fail, the error is terminal. 
When the copying fails (did you forget to adapt php_copy_file_ctx?), 
that's non-terminal, though. Reading through the code, I have the 
feeling that operations which do not call out to other operations, which 
can error, are terminal. And all others are non-terminal. E.g. failing 
to open a file is terminal. That the copying where the file opening is 
part of, failed, is non-terminal.
And then *additionally* some operations, which don't prevent success are 
also marked non-terminal - squeezing it into the boolean for the purpose 
of not erroring.
Which makes some sense to me, but the description in the RFC is really 
confusing here. And the meanings are muddied.

Thus, if I understand that correctly, there should be an unique mapping 
from error code to terminal. If we were to go with enums, we could make 
it trivially a property of the individual enum values instead.

Should StreamException be attached the non-terminal errors which are 
caused by the terminal errors? I.e. StreamException clearly is 
STREAM_ERROR_CODE_PERMISSION_DENIED for example, but it happens during a 
copy, so, should the information that a STREAM_ERROR_CODE_COPY_FAILED 
was caused by that, also be present on the StreamException?

Are stream errors which happen as part of a fully wrapped functionality 
marked as wrapper error as well? Like if the server sent an invalid TLS 
response to a file_get_contents("https://...") operation, making the 
whole operation fail? You obviously don't have access to the 
intermediary internal stream resource there, where the stream error is 
attached.
Is this what the logged errors section is about? Is that section talking 
about "php_stream_display_wrapper_errors", which can concat some errors? 
I see that this logic is mostly retained.

Do I understand the implementation correctly, that user error handlers 
can be called multiple times for a same operation? E.g. when copying a 
file, you'll get first a PERMISSION_DENIED then a COPY_FAILED? Should 
these not be somehow merged? Especially with global user_error handlers, 
these cannot be aware of the fact that the permission denied is part of 
anything else - at least not until possibly a second user_error 
invocation happens.
Also, is the internal resource used for e.g. `file_get_contents()` leaked 
into user error handlers? I'm not sure whether that's desirable. If 
that's intended, that's fine too, I think.

Further suggestion on stream_get_errors() - why not return a proper 
object instead of a loosely typed array? Proper typing, and creation is 
actually faster. Also "docref" is so... antiquated? maybe just 
"function" and have it contain the function name of the current operation.

Does stream_get_errors() ever reset? Looking at the code it doesn't seem 
so. It will just forever grow. E.g. `fwrite()` will report an error every 
single time when the buffer is full and a write is attempted. If errors 
aren't freed, that's just a memory leak (as long as the socket lives). 
This is a serious flaw.

Lastly, stream_get_errors() is overkill in a lot of cases (especially 
when using `fread()`/fwrite() on simple sockets). I just care about the 
last error code (there's just going to be one anyway). I'd love having a 
stream_get_last_error() returning just the code.


Overall, I like the direction of the RFC, but I'd like to see improved 
handling for "terminal error inside non-terminal operation having its 
own error" in particular. Enums are rather a suggestion, not a 
requirement, but they would be in my opinion very fitting here.


Thanks,

Bob

---

## #129293 — Jordi Boggiano — 2025-11-19T09:17:19+00:00

URL: https://externals.io/message/129289#129293 · In reply to: #129289

Hey Jakub,

Very nice improvement overall. Beyond the enum comment from Bob/Ignace
I would also think that stream_get_errors() could return an array of
StreamError objects instead of arrays?

readonly class StreamError
{
    public function __construct(
        public string $message,
        public int $code,
        public int $severity,
        public bool $terminal,
        public string $wrapper,
        public ?string $param = null,
        public ?string $docref = null,
    ) {}
}

This object could also be passed to the error handlers perhaps as:

    function(string $wrapper, ?resource $stream, StreamError $error): void

Just some ideas :)

Best,
Jordi

---

## #129294 — Lynn — 2025-11-19T09:42:06+00:00

URL: https://externals.io/message/129289#129294 · In reply to: #129289

> Hello,
>
> I would like to introduce a new stream error handling RFC that is part of
> my stream evolution work (PHP Foundation project funded by Sovereign Tech
> Fund) :
>
> https://wiki.php.net/rfc/stream_errors
>
> Kind regards,
>
> Jakub
>
>
The naming of "terminal" is a little confusing to me. Reading the name with
a bool made me think it was whether or not the CLI was being used, which
made little sense in the context of stream errors. After reading the
explanation "Terminal errors are those that prevent an operation from
completing (e.g., file not found, permission denied). Non-terminal errors
are warnings or notices that don't stop execution (e.g., buffer
truncation).", I feel like it might be more clear if this property was
named after what the result is, perhaps something like "operationBlocked"
or "operationPrevented".

---

## #129295 — ignace nyamagana butera — 2025-11-19T09:48:46+00:00

URL: https://externals.io/message/129289#129295 · In reply to: #129294

>
>
> 
>
> > […]
> The naming of "terminal" is a little confusing to me. Reading the name
> with a bool made me think it was whether or not the CLI was being used,
> which made little sense in the context of stream errors. After reading the
> explanation "Terminal errors are those that prevent an operation from
> completing (e.g., file not found, permission denied). Non-terminal errors
> are warnings or notices that don't stop execution (e.g., buffer
> truncation).", I feel like it might be more clear if this property was
> named after what the result is, perhaps something like "operationBlocked"
> or "operationPrevented".
>


I believe these types of issues can be resolved by replacing boolean values
by Enums, hence my suggestion. Enum would be more self explanatory and
would provide better insight on the outcome. I also like Jordi's
suggestion, anything that can help static analysis is the way to go IMHO.

Best regards,
Ignace

---

## #129296 — Lynn — 2025-11-19T09:54:00+00:00

URL: https://externals.io/message/129289#129296 · In reply to: #129295

On Wed, Nov 19, 2025 at 10:48 AM ignace nyamagana butera <
nyamsprod@gmail.com> wrote:

>
> 
>
> > […]
>
>
> I believe these types of issues can be resolved by replacing boolean
> values by Enums, hence my suggestion. Enum would be more self explanatory
> and would provide better insight on the outcome. I also like Jordi's
> suggestion, anything that can help static analysis is the way to go IMHO.
>
> Best regards,
> Ignace
>

I ended up removing this from my first reply, but an enum was also what I
thought of as it wouldn't surprise me if a 3rd state could be introduced:
fully prevented, fully executed but with warnings, and partially executed
like a buffer truncation. I just don't know enough about the underlying
errors/warnings to suggest this as alternative implementation.

---

## #129297 — Gina P. Banyard — 2025-11-19T11:14:36+00:00

URL: https://externals.io/message/129289#129297 · In reply to: #129289

> Hello,
>
> I would like to introduce a new stream error handling RFC that is part of my stream evolution work (PHP Foundation project funded by Sovereign Tech Fund) :
>
> https://wiki.php.net/rfc/stream_errors

Hi Jakub,

Thank you for working on this, this has been a long-standing pain point of our stream layer.
However, I do have various comments about the design of this.

Echoing multiple voices, please use enums rather than constants where applicable, and use an object rather than an associative array for individual stream errors.
As others have pointed out, the notion of (non-)"terminal" errors is not clear, and I'm struggling to understand what is the point of it?

How does this interact with the stream notification stuff?
(I guess surrounding PHP_STREAM_NOTIFY_SEVERITY_INFO and PHP_STREAM_NOTIFY_SEVERITY_ERR)

Regarding "docref" what is the point of including this in the error?
This is mainly used with php_docref to generate links to INI settings by referencing an XML ID that exists in doc-en, this does not seem applicable here.
I guess you added this due to the two usages of "streams.crypto" as a docref in main/streams/transports.c, but this ID doesn't exist, and I fear this might never have worked properly.
As such, I would recommend just getting rid of this.

The last thing that I feel *very* strongly about is that there should only be 3 modes:

- Silent
- Warnings
- Exceptions

As such, the cases where we currently emit a notice should either be promoted to warnings (which for some of them I don't even understand why they are just notices) or removed (mainly looking at the one in main/streams/userspace.c)
And the singular case which bailouts using `E_ERROR` should be converted to always throw an exception.
Bailouts cause all sorts of issues due to the lack of unwinding, things that exceptions solve.
This would also simplify both the internal, and userland API and get rid of the confusing notion of "errors" meaning "diagnostics/warnings".

Best regards,
Gina P. Banyard

---

## #129298 — Jakub Zelenka — 2025-11-19T11:52:35+00:00

URL: https://externals.io/message/129289#129298 · In reply to: #129291

Hi Bob,

Thanks for the feedback, the replies here also cover the feedback from
Jordi and Ignace.


> Why have you chosen a big list of constants rather than enums?
> I think we should push for enums where applicable, meaning enum
> StreamErrorMode, enum StreamErrorStore, enum StreamError.
>

Ok I will change it. StreamErrorMode and StreamErrorStore should be
straightforward. The code one should be probably named StreamErrorCode (to
not interact with what Jordi proposed) and think it will need to be backed
as there should be a straightforward way how to compare it with exception
code. I might need to extend the gen stub as I'm not sure it allows macro
import for enum value like for constants or I will need to come up with
some mapping. I just don't wan to duplicate the numbers. I will figure
something out.


> You define what a terminal error is, but does it correlate to specific
> error codes? Like, is a given error code always terminal or not
> terminal? Or can some error codes sometimes be terminal or not terminal
> depending on context?
> I've tried to look at the code, but I don't quite understand it, e.g.
> php_plain_files_rename: When chown or chmod fail, the error is terminal.
> When the copying fails (did you forget to adapt php_copy_file_ctx?),
> that's non-terminal, though. Reading through the code, I have the
> feeling that operations which do not call out to other operations, which
> can error, are terminal. And all others are non-terminal. E.g. failing
> to open a file is terminal. That the copying where the file opening is
> part of, failed, is non-terminal.
> And then *additionally* some operations, which don't prevent success are
> also marked non-terminal - squeezing it into the boolean for the purpose
> of not erroring.
> Which makes some sense to me, but the description in the RFC is really
> confusing here. And the meanings are muddied.
>

So currently the terminal / non terminal does not attach to code but it
could be done. The current logic is really just supposed to reflect what is
there already so the exception can be thrown in places where the function
would fail. So the errors after which the function fails are terminal and
the errors where the function still returns success are non terminal.

Thus, if I understand that correctly, there should be an unique mapping
> from error code to terminal. If we were to go with enums, we could make
> it trivially a property of the individual enum values instead.
>

I think making it property of enum make more sense. Then I can drop that
boolean property.


> Should StreamException be attached the non-terminal errors which are
> caused by the terminal errors? I.e. StreamException clearly is
> STREAM_ERROR_CODE_PERMISSION_DENIED for example, but it happens during a
> copy, so, should the information that a STREAM_ERROR_CODE_COPY_FAILED
> was caused by that, also be present on the StreamException?
>

I think I get what you mean from the user point of view but I'm not sure
how could this be reasonably linked.

I could maybe check during stream error if there is EG(exception) it's a
StreamException and if so, I could the update it with this error (e.g. some
property that would hold those error can could be retrieved). I guess it
could be potentially extended for terminal errors as well so it could have
method like getAllErrors which would return all errors because sometimes
there can be more terminal errors and some of them might get lost (last one
will be added). However this would work just for exception so maybe more
generic solution is needed here (see below).


> Are stream errors which happen as part of a fully wrapped functionality
> marked as wrapper error as well? Like if the server sent an invalid TLS
> response to a file_get_contents("https://...") operation, making the
> whole operation fail? You obviously don't have access to the
> intermediary internal stream resource there, where the stream error is
> attached.
>

I actually thought about this yesterday that it's not ideal that some
errors might get lost in this way so I think it should go to wrapper errors
as well.


> Is this what the logged errors section is about? Is that section talking
> about "php_stream_display_wrapper_errors", which can concat some errors?
> I see that this logic is mostly retained.
>

Yeah the logged errors is an existing mechanism for grouping errors to a
single one (concatenating message). The display is a bit messy because it
separated them by new line or <br/> (if html errors enabled) but I just
kept it to limit BC impact.


> Do I understand the implementation correctly, that user error handlers
> can be called multiple times for a same operation? E.g. when copying a
> file, you'll get first a PERMISSION_DENIED then a COPY_FAILED? Should
> these not be somehow merged? Especially with global user_error handlers,
> these cannot be aware of the fact that the permission denied is part of
> anything else - at least not until possibly a second user_error
> invocation happens.
>

This is somehow related to the exception error grouping as it requires some
sort of linking between the errors.

I guess to make this work we would need some top level wrapping similar to
what logged errors do but instead of concatenating, it would group the
errors in a better way which could then be used in exception or handler.
This would, however, increase the complexity significantly as it is
possible to nest the stream calls (e.g. stream calls in notification
callback or in the new error handler) so there would probably need to be
some stack. Also I'm not sure about the API. Should we pass always array of
errors to the callback (which would mostly have just one element anyway or
somehow chain the StreamError object (something like previousError()) and
what message should be used in exception (e.g. last error and then helper
function to get all errors)?

I'm willing to look into this but would like to know if this is something
important for user space and what is the usual flow how could this be used
in frameworks and so on. In other words I would like to get more input to
make sure that this is really needed as it requires quite a bit of effort
to do.


> Also, is the internal resource used for e.g. `file_get_contents()` leaked
> into user error handlers? I'm not sure whether that's desirable. If
> that's intended, that's fine too, I think.
>
>
Currently yes. I need to actually double check the consequences of that as
I didn't really think about internal resources.


> Further suggestion on stream_get_errors() - why not return a proper
> object instead of a loosely typed array? Proper typing, and creation is
> actually faster. Also "docref" is so... antiquated? maybe just
> "function" and have it contain the function name of the current operation.
>
>
Yeah I will go for it and introduce StreamError as Jordi suggested with
slight modification to use enum and dropping terminal and docref.


> Does stream_get_errors() ever reset? Looking at the code it doesn't seem
> so. It will just forever grow. E.g. `fwrite()` will report an error every
> single time when the buffer is full and a write is attempted. If errors
> aren't freed, that's just a memory leak (as long as the socket lives).
> This is a serious flaw.
>
> Lastly, stream_get_errors() is overkill in a lot of cases (especially
> when using `fread()`/fwrite() on simple sockets). I just care about the
> last error code (there's just going to be one anyway). I'd love having a
> stream_get_last_error() returning just the code.
>
>
I guess this makes more sense but it kind of also implies the top level
wrapping as it should contain all errors in the call. Or alternatively it
could be just a ring with limited number of errors be behave in the same
way like openssl_error_string. I guess it depends if we go with that top
level wrapping.

Cheers,

Jakub

---

## #129299 — Jakub Zelenka — 2025-11-19T11:55:58+00:00

URL: https://externals.io/message/129289#129299 · In reply to: #129296

Hi,



>
>
> On Wed, Nov 19, 2025 at 10:48 AM ignace nyamagana butera <
> nyamsprod@gmail.com> wrote:
>
> > […]
>
> I ended up removing this from my first reply, but an enum was also what I
> thought of as it wouldn't surprise me if a 3rd state could be introduced:
> fully prevented, fully executed but with warnings, and partially executed
> like a buffer truncation. I just don't know enough about the underlying
> errors/warnings to suggest this as alternative implementation.
>

I don't think we will add another state. The enum based approach seems most
reasonable to me. I should also change the name terminal / non terminal to
terminating / non terminating as I think that's the correct name for this...

Cheers,

Jakub

---

## #129307 — Jakub Zelenka — 2025-11-19T15:38:43+00:00

URL: https://externals.io/message/129289#129307 · In reply to: #129297

Hi Gina,



> On Tuesday, 18 November 2025 at 18:41, Jakub Zelenka <bukka@php.net>
> wrote:
>
> Hello,
>
> I would like to introduce a new stream error handling RFC that is part of
> my stream evolution work (PHP Foundation project funded by Sovereign Tech
> Fund) :
>
> https://wiki.php.net/rfc/stream_errors
>
>
> Hi Jakub,
>
> Thank you for working on this, this has been a long-standing pain point of
> our stream layer.
> However, I do have various comments about the design of this.
>
> Echoing multiple voices, please use enums rather than constants where
> applicable, and use an object rather than an associative array for
> individual stream errors.
> As others have pointed out, the notion of (non-)"terminal" errors is not
> clear, and I'm struggling to understand what is the point of it?
>
>
I just answered this in replay to Bob. The non terminating errors are those
that don't change return value of the function (it means not returning
failure). Some of those errors are still useful and users should be
notified but they are not critical for correct result. This was mainly
introduced for exceptions as those cases should not throw but it still
makes sense to somehow notify users (e.g. store the error).


> How does this interact with the stream notification stuff?
> (I guess surrounding PHP_STREAM_NOTIFY_SEVERITY_INFO and
> PHP_STREAM_NOTIFY_SEVERITY_ERR)
>
>
It doesn't interact with it. Although PHP_STREAM_NOTIFY_SEVERITY_ERR
somehow overlaps with it but it's limited in use (currently used only in
ftp and http wrapper). Obviously I couldn't just use notifications and I
needed to keep them working so the only possibility was to introduce a new
API that handles just errors. Going forward I'm not
sure PHP_STREAM_NOTIFY_SEVERITY_ERR should be kept but that's more a future
scope I guess.


> Regarding "docref" what is the point of including this in the error?
> This is mainly used with php_docref to generate links to INI settings by
> referencing an XML ID that exists in doc-en, this does not seem applicable
> here.
> I guess you added this due to the two usages of "streams.crypto" as a
> docref in main/streams/transports.c, but this ID doesn't exist, and I
> fear this might never have worked properly.
> As such, I would recommend just getting rid of this.
>
>
Agreed I'm not going to expose it. I will keep it just for error mode to
keep it the same but I guess it might be better to drop it completely in
the future.


> The last thing that I feel *very* strongly about is that there should only
> be 3 modes:
>
>    - Silent
>    - Warnings
>    - Exceptions
>
>
> As such, the cases where we currently emit a notice should either be
> promoted to warnings (which for some of them I don't even understand why
> they are just notices) or removed (mainly looking at the one in
> main/streams/userspace.c)
>
And the singular case which bailouts using `E_ERROR` should be converted to
> always throw an exception.
> Bailouts cause all sorts of issues due to the lack of unwinding, things
> that exceptions solve.
> This would also simplify both the internal, and userland API and get rid
> of the confusing notion of "errors" meaning "diagnostics/warnings".
>
>
My aim is really not to touch the current logic and the error
classification except one case where reporting was done accidentally. I
think that non terminating errors make some sense as they give some hint
that something could be improved but it's not necessarily preventing the
functioning. This is something that has been already there and I don't
think it needs to be changed as part of this proposal.

Cheers,

Jakub

---

## #129310 — Larry Garfield — 2025-11-19T16:33:12+00:00

URL: https://externals.io/message/129289#129310 · In reply to: #129289

> Hello,
>
> I would like to introduce a new stream error handling RFC that is part 
> of my stream evolution work (PHP Foundation project funded by Sovereign 
> Tech Fund) :
>
> https://wiki.php.net/rfc/stream_errors
>
> Kind regards,
>
> Jakub

HI Jakub.

I agree with what others have said so far.  I'm going to ask a little bit further, though.

AIUI, there's two main issues with the stream API:

1. It's very inconsistent.
2. It's very clunky, non-obvious, and hard to use if you don't know exactly what you're doing.

This RFC seems to be addressing the first point, which is fine.  However, should we be trying to smooth out the current unpleasant API, or should the effort be put toward a more intuitive API that is smoother from the start?  This RFC could be a stepping stone toward that, I'm not sure, but if so that's not clear to me.

Are there any longer term plans here for a more complete stream overhaul?

--Larry Garfield

---

## #129311 — Bob Weinand — 2025-11-19T16:37:02+00:00

URL: https://externals.io/message/129289#129311 · In reply to: #129298

Hey Jakub,

thanks for the detailed reply.


> The code one should be probably named StreamErrorCode (to not interact 
> with what Jordi proposed) and think it will need to be backed as there 
> should be a straightforward way how to compare it with exception code. 
> I might need to extend the gen stub as I'm not sure it allows macro 
> import for enum value like for constants or I will need to come up 
> with some mapping. I just don't wan to duplicate the numbers. I will 
> figure something out.

How important is it to have exception code?

I found that for our purposes we generally skip the exception code (i.e. 
keep it at zero).
As a simple example, ErrorException does take two integers - one for 
severity, and one for code, instead of using the severity as code.
I would propose something similar here: call it StreamError and provide 
a public $error property for the actual enum, rather than squeezing it 
into $code.

This also solves your gen-stub issues by making them unncessary.


>     Should StreamException be attached the non-terminal errors which are
>     caused by the terminal errors? I.e. StreamException clearly is
>     STREAM_ERROR_CODE_PERMISSION_DENIED for example, but it happens
>     during a
>     copy, so, should the information that a STREAM_ERROR_CODE_COPY_FAILED
>     was caused by that, also be present on the StreamException?
>
>
> I think I get what you mean from the user point of view but I'm not 
> sure how could this be reasonably linked.
>
> I could maybe check during stream error if there is EG(exception) it's 
> a StreamException and if so, I could the update it with this error 
> (e.g. some property that would hold those error can could be 
> retrieved). I guess it could be potentially extended for terminal 
> errors as well so it could have method like getAllErrors which would 
> return all errors because sometimes there can be more terminal errors 
> and some of them might get lost (last one will be added). However this 
> would work just for exception so maybe more generic solution is needed 
> here (see below).

Replying below to this.


>     Are stream errors which happen as part of a fully wrapped
>     functionality
>     marked as wrapper error as well? Like if the server sent an
>     invalid TLS
>     response to a file_get_contents("https://...") operation, making the
>     whole operation fail? You obviously don't have access to the
>     intermediary internal stream resource there, where the stream
>     error is
>     attached.
>
>
> I actually thought about this yesterday that it's not ideal that some 
> errors might get lost in this way so I think it should go to wrapper 
> errors as well.

If we properly wrap the nested operations into a single error, then it 
would be automatically part of the wrapper error, with no need to 
explicitly add it to stream error.


>     Is this what the logged errors section is about? Is that section
>     talking
>     about "php_stream_display_wrapper_errors", which can concat some
>     errors?
>     I see that this logic is mostly retained.
>
>
> Yeah the logged errors is an existing mechanism for grouping errors to 
> a single one (concatenating message). The display is a bit messy 
> because it separated them by new line or <br/> (if html errors 
> enabled) but I just kept it to limit BC impact.

I don't think changing the display / grouping here would be problematic 
with respect to BC. But I get that this initial draft tries to limit 
what it changes.


>     Do I understand the implementation correctly, that user error
>     handlers
>     can be called multiple times for a same operation? E.g. when
>     copying a
>     file, you'll get first a PERMISSION_DENIED then a COPY_FAILED? Should
>     these not be somehow merged? Especially with global user_error
>     handlers,
>     these cannot be aware of the fact that the permission denied is
>     part of
>     anything else - at least not until possibly a second user_error
>     invocation happens.
>
>
> This is somehow related to the exception error grouping as it requires 
> some sort of linking between the errors.
>
> I guess to make this work we would need some top level wrapping 
> similar to what logged errors do but instead of concatenating, it 
> would group the errors in a better way which could then be used in 
> exception or handler. This would, however, increase the complexity 
> significantly as it is possible to nest the stream calls (e.g. stream 
> calls in notification callback or in the new error handler) so there 
> would probably need to be some stack. Also I'm not sure about the API. 
> Should we pass always array of errors to the callback (which would 
> mostly have just one element anyway or somehow chain the StreamError 
> object (something like previousError()) and what message should be 
> used in exception (e.g. last error and then helper function to get all 
> errors)?
>
> I'm willing to look into this but would like to know if this is 
> something important for user space and what is the usual flow how 
> could this be used in frameworks and so on. In other words I would 
> like to get more input to make sure that this is really needed as it 
> requires quite a bit of effort to do.

Doing this work will definitely tidy up the whole error story. It's not 
fundamentally crucial, but it definitely will make for a nicer API.

And yes, chaining StreamError sounds and nesting exceptions to $previous 
sounds like the most straightforward way.

Also a possibility for exceptions: this might be a bit of work, but you 
could insert a fake frame for exceptions to indicate when an error 
appears as a sub-operation. Like:

StreamException: Permission denied
#0 [internal function]: fopen("target.php", "w+")
#1 [internal function]: copy("source.php", "target.php")
#2 ...

I also like the suggestion by Jordi to pass the StreamError right away 
into the user handler.


>     Also, is the internal resource used for e.g. `file_get_contents()`
>     leaked
>     into user error handlers? I'm not sure whether that's desirable. If
>     that's intended, that's fine too, I think.
>
>
> Currently yes. I need to actually double check the consequences of 
> that as I didn't really think about internal resources.

If we decide to go with completely wrapping and calling the user error 
handler only once per top-level operation, this point would be moot anyway.

>     Does stream_get_errors() ever reset? Looking at the code it
>     doesn't seem
>     so. It will just forever grow. E.g. `fwrite()` will report an error
>     every
>     single time when the buffer is full and a write is attempted. If
>     errors
>     aren't freed, that's just a memory leak (as long as the socket
>     lives).
>     This is a serious flaw.
>
>     Lastly, stream_get_errors() is overkill in a lot of cases (especially
>     when using `fread()`/fwrite() on simple sockets). I just care about the
>     last error code (there's just going to be one anyway). I'd love
>     having a
>     stream_get_last_error() returning just the code.
>
>
> I guess this makes more sense but it kind of also implies the top 
> level wrapping as it should contain all errors in the call. Or 
> alternatively it could be just a ring with limited number of errors be 
> behave in the same way like openssl_error_string. I guess it depends 
> if we go with that top level wrapping.

I feel like the top-level wrapping would simplify things a lot (from 
point of addressing shortcomings), and if this just works like 
json_get_last_error(), where you only ever see the last error, there's 
no risks of being unbounded nor having arbitrary size limits.


The only disadvantage of top-level wrapping is probably a bit more 
book-keeping as in "storing that there is an outer operation before 
invoking an inner operation"? Haven't thought much about the actual 
implementation of this, but should be doable.


Thanks,
Bob

---

## #129316 — Jakub Zelenka — 2025-11-19T22:41:27+00:00

URL: https://externals.io/message/129289#129316 · In reply to: #129310

Hi,

On Wed, Nov 19, 2025 at 5:35 PM Larry Garfield <larry@garfieldtech.com>
wrote:

> 
> > […]
>
> HI Jakub.
>
> I agree with what others have said so far.  I'm going to ask a little bit
> further, though.
>
> AIUI, there's two main issues with the stream API:
>
> 1. It's very inconsistent.
> 2. It's very clunky, non-obvious, and hard to use if you don't know
> exactly what you're doing.
>
> This RFC seems to be addressing the first point, which is fine.  However,
> should we be trying to smooth out the current unpleasant API, or should the
> effort be put toward a more intuitive API that is smoother from the start?
> This RFC could be a stepping stone toward that, I'm not sure, but if so
> that's not clear to me.
>
> Are there any longer term plans here for a more complete stream overhaul?
>
>
This RFC is part of the bigger effort to address various stream issues and
provide other stream related improvements that I selected based on my TODO
list. You can see more detailed description of the whole scope in this
foundation blog:
https://thephp.foundation/blog/2025/10/30/php-streams-evolution/ .

The overhaul of the whole API is out of scope as there are lots of unknowns
and would require longer migration. It is thus harder to deliver in the
selected time frame. It doesn't mean that it won't happen. It's just out of
scope for this block of work and I don't have specific plans for it.

Kind regards,

Jakub

---

## #129317 — Jakub Zelenka — 2025-11-19T22:58:57+00:00

URL: https://externals.io/message/129289#129317 · In reply to: #129311

Hi Bob,



> Hey Jakub,
>
> thanks for the detailed reply.
> 
>
> The code one should be probably named StreamErrorCode (to not interact
> with what Jordi proposed) and think it will need to be backed as there
> should be a straightforward way how to compare it with exception code. I
> might need to extend the gen stub as I'm not sure it allows macro import
> for enum value like for constants or I will need to come up with some
> mapping. I just don't wan to duplicate the numbers. I will figure something
> out.
>
> How important is it to have exception code?
>
I think the exception code could be quite useful for checking for specific
errors. It's much better than trying to match it by error message which I
saw in past used in normal error handlers. So I can see definitely use case
for that. It might be also possible to group those erors if enums are used
so users could just match specific group of errors.

> I found that for our purposes we generally skip the exception code (i.e.
> keep it at zero).
> As a simple example, ErrorException does take two integers - one for
> severity, and one for code, instead of using the severity as code.
>
Severity is almost always warning which I don't think is a good
representation for code. I saw error codes used in various application and
I think they are useful. I don't think it hurts to have them. The
implementation of that enum should not be a big problem. I just need to
figure out how to make it nice.

> I would propose something similar here: call it StreamError and provide a
> public $error property for the actual enum, rather than squeezing it into
> $code.
>
I'm not sure I understand this. The code is a generic identifier for the
error class that can be matched. StreamError would be the actual
representation containing the message and other info - this cannot be
matched in a generic way.

> Is this what the logged errors section is about? Is that section talking
> > […]
>
> Yeah the logged errors is an existing mechanism for grouping errors to a
> single one (concatenating message). The display is a bit messy because it
> separated them by new line or <br/> (if html errors enabled) but I just
> kept it to limit BC impact.
>
> I don't think changing the display / grouping here would be problematic
> with respect to BC. But I get that this initial draft tries to limit what
> it changes.
>
Exactly I would like to limit the external changes.

>
> Do I understand the implementation correctly, that user error handlers
> > […]
>
> This is somehow related to the exception error grouping as it requires
> some sort of linking between the errors.
>
> I guess to make this work we would need some top level wrapping similar to
> what logged errors do but instead of concatenating, it would group the
> errors in a better way which could then be used in exception or handler.
> This would, however, increase the complexity significantly as it is
> possible to nest the stream calls (e.g. stream calls in notification
> callback or in the new error handler) so there would probably need to be
> some stack. Also I'm not sure about the API. Should we pass always array of
> errors to the callback (which would mostly have just one element anyway or
> somehow chain the StreamError object (something like previousError()) and
> what message should be used in exception (e.g. last error and then helper
> function to get all errors)?
>
> I'm willing to look into this but would like to know if this is something
> important for user space and what is the usual flow how could this be used
> in frameworks and so on. In other words I would like to get more input to
> make sure that this is really needed as it requires quite a bit of effort
> to do.
>
> Doing this work will definitely tidy up the whole error story. It's not
> fundamentally crucial, but it definitely will make for a nicer API.
>
> And yes, chaining StreamError sounds and nesting exceptions to $previous
> sounds like the most straightforward way.
>
> Also a possibility for exceptions: this might be a bit of work, but you
> could insert a fake frame for exceptions to indicate when an error appears
> as a sub-operation. Like:
>
> StreamException: Permission denied
> #0 [internal function]: fopen("target.php", "w+")
> #1 [internal function]: copy("source.php", "target.php")
> #2 ...
>
> I will check this out.

> I also like the suggestion by Jordi to pass the StreamError right away
> into the user handler.
>
>
> Yeah agreed.


> Also, is the internal resource used for e.g. `file_get_contents()` leaked
> > […]
> Currently yes. I need to actually double check the consequences of that as
> I didn't really think about internal resources.
>
> If we decide to go with completely wrapping and calling the user error
> handler only once per top-level operation, this point would be moot anyway.
>
>
>
> Does stream_get_errors() ever reset? Looking at the code it doesn't seem
> > […]
> I guess this makes more sense but it kind of also implies the top level
> wrapping as it should contain all errors in the call. Or alternatively it
> could be just a ring with limited number of errors be behave in the same
> way like openssl_error_string. I guess it depends if we go with that top
> level wrapping.
>
> I feel like the top-level wrapping would simplify things a lot (from point
> of addressing shortcomings), and if this just works like
> json_get_last_error(), where you only ever see the last error, there's no
> risks of being unbounded nor having arbitrary size limits.
>
Yeah I think it would be more logical and improve things so I will check it
out and see when I have my next stream errors slot (should be later next
month).

Cheers,

Jakub

---

## #129318 — Bob Weinand — 2025-11-20T00:11:05+00:00

URL: https://externals.io/message/129289#129318 · In reply to: #129317

Hey Jakub,


> 
>
>     
> > […]
>
>     How important is it to have exception code?
>
> I think the exception code could be quite useful for checking for 
> specific errors. It's much better than trying to match it by error 
> message which I saw in past used in normal error handlers. So I can 
> see definitely use case for that. It might be also possible to group 
> those erors if enums are used so users could just match specific group 
> of errors.

For the purpose of grouping it would be vastly preferable to add 
functions to the enum class to mark enum values as pertaining to 
specific groups "function isIoError(): bool", "function 
isFileSystemError(): bool" etc. or just simply "function errorGroup(): 
StreamErrorGroup" which is another enum with some grooups like "Io", 
"Filesystem" etc. rather than comparing ranges.


>     I found that for our purposes we generally skip the exception code
>     (i.e. keep it at zero).
>     As a simple example, ErrorException does take two integers - one
>     for severity, and one for code, instead of using the severity as code.
>
> Severity is almost always warning which I don't think is a good 
> representation for code. I saw error codes used in various application 
> and I think they are useful. I don't think it hurts to have them. The 
> implementation of that enum should not be a big problem. I just need 
> to figure out how to make it nice.
>
>     I would propose something similar here: call it StreamError and
>     provide a public $error property for the actual enum, rather than
>     squeezing it into $code.
>
> I'm not sure I understand this. The code is a generic identifier for 
> the error class that can be matched. StreamError would be the actual 
> representation containing the message and other info - this cannot be 
> matched in a generic way.


My point here is that $code generally does not get used for our 
Exceptions. Whenever we need to attach extra information to an 
exception, we do it as extraneous properties. (That's what my example 
with ErrorException was about.)

I.e. ignore the existence of $code (just assign zero).

And add an extra property for the StreamError enum (which now needs no 
backing).

class StreamException extends Exception {
     public __construct(
         public StreamError $error,
         public string $wrapperName,
         string $message = "",
         public string|null $param = "",
         ?Throwable $previous = null
     ) {
         parent::__construct($message, 0, $previous);
     }
}

Does this make more sense, described as code?


Thank you,
Bob

---

## #129326 — Jakub Zelenka — 2025-11-20T12:03:08+00:00

URL: https://externals.io/message/129289#129326 · In reply to: #129318

Hi Bob,



> Hey Jakub,
> 
>
> 
>
> > […]
> I think the exception code could be quite useful for checking for specific
> errors. It's much better than trying to match it by error message which I
> saw in past used in normal error handlers. So I can see definitely use case
> for that. It might be also possible to group those erors if enums are used
> so users could just match specific group of errors.
>
> For the purpose of grouping it would be vastly preferable to add functions
> to the enum class to mark enum values as pertaining to specific groups
> "function isIoError(): bool", "function isFileSystemError(): bool" etc. or
> just simply "function errorGroup(): StreamErrorGroup" which is another enum
> with some grooups like "Io", "Filesystem" etc. rather than comparing ranges.
>
>
> Yeah that's what I was thinking. Internally I would still probably
represent it as num ranges (as it is now) but userspace should use those
enum functions.


> I found that for our purposes we generally skip the exception code (i.e.
> > […]
> Severity is almost always warning which I don't think is a good
> representation for code. I saw error codes used in various application and
> I think they are useful. I don't think it hurts to have them. The
> implementation of that enum should not be a big problem. I just need to
> figure out how to make it nice.
>
> > […]
> I'm not sure I understand this. The code is a generic identifier for the
> error class that can be matched. StreamError would be the actual
> representation containing the message and other info - this cannot be
> matched in a generic way.
>
>
> My point here is that $code generally does not get used for our
> Exceptions. Whenever we need to attach extra information to an exception,
> we do it as extraneous properties. (That's what my example with
> ErrorException was about.)
>
> I.e. ignore the existence of $code (just assign zero).
>
> And add an extra property for the StreamError enum (which now needs no
> backing).
>
> class StreamException extends Exception {
>     public __construct(
>         public StreamError $error,
>         public string $wrapperName,
>         string $message = "",
>         public string|null $param = "",
>         ?Throwable $previous = null
>     ) {
>         parent::__construct($message, 0, $previous);
>     }
> }
>
> Does this make more sense, described as code?
>

As I see what you mean now. I would prefer to use StreamError name for the
class holding all the details including code, wrapper name, message and
param as proposed by Jordi because this could be also passed to handler and
retrieved from the stored errors. It just seems not right to use
StreamException as a container without being thrown (is that done
anywhere?) so I think separate class for handler and stored errors (or
single last error) seems cleaner. Although StreamException would be then
quite similar. I could pass StreamError there as a property but then it
would duplicate the message so not sure.

In any case I think it's better to call that enum StreamErrorCode. I will
still find a clean way to map it to the defines (STREAM_ERROR_CODE_*
macros) because that's what I use internally to set code in the error. So
not using int value for the exception code won't make that much difference
from the implementation PoV.

Kind regards,

Jakub

---

## #129352 — Bob Weinand — 2025-11-21T01:57:21+00:00

URL: https://externals.io/message/129289#129352 · In reply to: #129326

Hey Jakub,


>
>     My point here is that $code generally does not get used for our
>     Exceptions. Whenever we need to attach extra information to an
>     exception, we do it as extraneous properties. (That's what my
>     example with ErrorException was about.)
>
>     I.e. ignore the existence of $code (just assign zero).
>
>     And add an extra property for the StreamError enum (which now
>     needs no backing).
>
>     class StreamException extends Exception {
>         public __construct(
>             public StreamError $error,
>             public string $wrapperName,
>             string $message = "",
>             public string|null $param = "",
>             ?Throwable $previous = null
>         ) {
>             parent::__construct($message, 0, $previous);
>         }
>     }
>
>     Does this make more sense, described as code?
>
>
> As I see what you mean now. I would prefer to use StreamError name for 
> the class holding all the details including code, wrapper name, 
> message and param as proposed by Jordi because this could be also 
> passed to handler and retrieved from the stored errors. It just seems 
> not right to use StreamException as a container without being thrown 
> (is that done anywhere?) so I think separate class for handler and 
> stored errors (or single last error) seems cleaner. Although 
> StreamException would be then quite similar. I could pass StreamError 
> there as a property but then it would duplicate the message so not sure.
>
> In any case I think it's better to call that enum StreamErrorCode. I 
> will still find a clean way to map it to the defines 
> (STREAM_ERROR_CODE_* macros) because that's what I use internally to 
> set code in the error. So not using int value for the exception code 
> won't make that much difference from the implementation PoV.

I don't mind the name, whether you call it StreamError or 
StreamErrorCode. Or maybe call the class "StreamFailure" and the enum 
"StreamError"? Just a suggestion, I don't care too much about the actual 
names.

For the internal implementation, does it actually matter passing around 
an int value or a char pointer with the name? Which would allow you to 
directly pass it into the enum lookup. But yup, do whatever fits you 
best here :-)

(Ranty tangent: Umm, what's even the internal proper way to get an enum 
value? Manual zend_hash_find_ptr(CE_CONSTANTS_TABLE(ce), constant_name) 
including zend_update_class_constant()?! We ought to figure a way to 
create the internal enum case objects at compile time, then we could 
just reference them directly... Working with enums internally can be 
annoying and fetching *feels* slow (even if it's just a HashTable lookup).)


Bob

---

## #129594 — Arnaud Le Blanc — 2025-12-12T12:29:02+00:00

URL: https://externals.io/message/129289#129594 · In reply to: #129289

Hi Jakub,


>
> Hello,
>
> I would like to introduce a new stream error handling RFC that is part of my stream evolution work (PHP Foundation project funded by Sovereign Tech Fund) :
>
> https://wiki.php.net/rfc/stream_errors
>
> Kind regards,
>
> Jakub

Thank you for working on this.

The RFC doesn't specify when exactly the error_handler is invoked
(especially in case of non-fatal errors). Is it as soon as the error
happens, or are invocations batched at the end of the operation?

The reason I'm asking is because there is a long track of bugs related
to the global error handler [1], and it's likely that the
error_handler proposed here could suffer from the same issues. For
example the error_handler can reenter the operation being performed,
or change the state of the stream. For safety and simplicity, I would
suggest that error_handler calls are delayed until just before
returning to user code.

[1] https://github.com/php/php-src/issues/20018

Best Regards,
Arnaud

---

## #129718 — Jakub Zelenka — 2025-12-29T18:52:44+00:00

URL: https://externals.io/message/129289#129718 · In reply to: #129289

> Hello,
>
> I would like to introduce a new stream error handling RFC that is part of
> my stream evolution work (PHP Foundation project funded by Sovereign Tech
> Fund) :
>
> https://wiki.php.net/rfc/stream_errors
>
>
 Hi, I just published version 2.0 which is a significant redesign including:

- Introducing StreamErrorStore, StreamErrorMode and StreamErrorCode enums
(the code also includes various suggested helper methods). The code is
backed (int) because I need to keep the number to easily match the category
and simplify the mapping. I think that in this case a backed enum is better.

- The error data are now in a StreamError class instead of an associative
array. This also simplifies StreamException which now has just a single
method to return the StreamError instance. The error handler callback
signature was also simplified to take just a single StreamError parameter
instead of multiple individual parameters.

- Errors are now grouped per operation and reported at the end of the call.
This also supports nested calls (e.g. in user streams) so they don't
overlap. And it delays the execution of error handlers (not just the stream
error callback but also the usual error handler if default standard error
triggering is used) which should be safer as noted by Arnaud.

- The storing of errors is done at the end of the operation grouping and
contains only the last grouped errors. So the function name was changed to
stream_get_last_error(). It returns just a single StreamError which has a
next property pointing to the next error if there is any.

- Stream is no longer exposed and errors are not collected on streams but
globally in the same way as wrappers. It is actually no longer even
collected per wrapper because it doesn't make much sense when the errors
are grouped per operation.

- Terminal (and NonTerminal) was renamed to Terminating (and
NonTerminating).

- Invalid enum types for context options (error_mode and error_store) now
throw TypeError.

- Implemented operation pooling to minimize memory allocations during error
handling (pre-allocated pool for up to 8 nested operations).

I hope this addresses all concerns.

Kind regards,

Jakub

---

## #129719 — Morgan — 2025-12-29T23:22:52+00:00

URL: https://externals.io/message/129289#129719 · In reply to: #129718

> 
>   Hi, I just published version 2.0 which is a significant redesign 
> including:
> 
> - Introducing ... StreamErrorCode 
> enums.... The 
> code is backed (int) because I need to keep the number to easily match 
> the category and simplify the mapping. I think that in this case a 
> backed enum is better.
> 

Just spitballing here, but perhaps a StreamErrorCategory enum? The Code 
could have a method/property that matches it to the corresponding 
Category; categorising errors of different kinds can be done by 
branching on the Category, rather than (possibly multiple) is*Error() tests.

---

## #129722 — Christian Schneider — 2025-12-30T08:22:43+00:00

URL: https://externals.io/message/129289#129722 · In reply to: #129718

Am 29.12.2025 um 19:52 schrieb Jakub Zelenka <bukka@php.net>:
> - The storing of errors is done at the end of the operation grouping and contains only the last grouped errors. So the function name was changed to stream_get_last_error(). It returns just a single StreamError which has a next property pointing to the next error if there is any.

I assume the chaining was based on Exception chaining but the example code under
	https://wiki.php.net/rfc/stream_errors#error_chaining
looks a bit clunky to me and I was wondering if returning an array of StreamError would not be more straightforward, i.e. one could then use foreach, empty(), `count()`, `array_first()`, `array_last()`, `array_find()` etc. instead of methods like while, $e->count(), $e->hasCode() which would make it feel more idiomatic to me.

But then again it might be a matter of taste and/or I might have missed something.

Regards,
- Chris

---

## #130167 — Jakub Zelenka — 2026-02-25T12:37:47+00:00

URL: https://externals.io/message/129289#130167 · In reply to: #129719

Hi,



> 
> > […]
>
> Just spitballing here, but perhaps a StreamErrorCategory enum? The Code
> could have a method/property that matches it to the corresponding
> Category; categorising errors of different kinds can be done by
> branching on the Category, rather than (possibly multiple) is*Error()
> tests.
>

This is an interesting idea but it wouldn't work because some categories
are overlapping. So is*Error functions seem better fit here.

Kind regards,

Jakub

---

## #130168 — Jakub Zelenka — 2026-02-25T13:17:36+00:00

URL: https://externals.io/message/129289#130168 · In reply to: #129722

Hi,

On Tue, Dec 30, 2025 at 9:24 AM Christian Schneider <cschneid@cschneid.com>
wrote:

> Am 29.12.2025 um 19:52 schrieb Jakub Zelenka <bukka@php.net>:
> > […]
> contains only the last grouped errors. So the function name was changed to
> stream_get_last_error(). It returns just a single StreamError which has a
> next property pointing to the next error if there is any.
>
> I assume the chaining was based on Exception chaining but the example code
> under
>         https://wiki.php.net/rfc/stream_errors#error_chaining
> looks a bit clunky to me and I was wondering if returning an array of
> StreamError would not be more straightforward, i.e. one could then use
> foreach, empty(), `count()`, `array_first()`, `array_last()`, `array_find()` etc.
> instead of methods like while, $e->count(), $e->hasCode() which would make
> it feel more idiomatic to me.
>
>
I thought about it and I think the exception like chaining makes a bit more
sense here. The thing is that in majority cases there will be only one
error so it would be most of the time array with just one element which
seems a bit wasteful. But if others also feel that array would be better, I
wouldn't mind to do follow up RFC as I don't really feel strongly about it.
Just let me know during the vote and if there's more people asking for it,
I will do a follow up RFC. Alternatively it could just implement iterator
or array access, which I was thinking about, but not sure if it's not too
messy.

Kind regards,

Jakub

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## #130169 — Jakub Zelenka — 2026-02-25T13:21:50+00:00

URL: https://externals.io/message/129289#130169 · In reply to: #129289

Hi,



> Hello,
>
> I would like to introduce a new stream error handling RFC that is part of
> my stream evolution work (PHP Foundation project funded by Sovereign Tech
> Fund) :
>
> https://wiki.php.net/rfc/stream_errors
>
>
As there has not been much discussion and keeping the patch up to date is a
slight pain, I plan to open voting on Friday (27/02/26) evening or Saturday
(28/02/26) morning unless some changes are required ofc.

Kind regards

Jakub

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