# Possible Bug with Interface, Constants and Inheritance - Thread: https://externals.io/message/94276 - Original archive: https://news-web.php.net/php.internals/94276 - Started by k@rl.pflaesterer.de on 2016-06-27T13:01:50+00:00 - Messages: 11 - Reply by email to internals@lists.php.net - More for agents: search with https://externals.io/search.md?q={query} · RFCs at https://externals.io/rfc.md · JSON API at https://externals.io/api · documentation at https://externals.io/llms.txt --- ## #94276 — k@rl.pflaesterer.de — 2016-06-27T13:01:50+00:00 URL: https://externals.io/message/94276#94276 Hi, I'm not sure if it's a bug or not. Consider these simple script: php -v PHP 7.0.7 (cli) (built: May 27 2016 15:22:32) ( NTS ) Copyright (c) 1997-2016 The PHP Group Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies ~> php -a -ddispplay_errors=On Interactive shell php > interface I1 { const C1 = '';} php > class C3 implements I1 { const C1 = 'c2';} php > $c3 = new C3; php > var_dump($c3::C1); string(2) "c2" Is this always the correkt behaviour? KP --- ## #94277 — Andreas Heigl — 2016-06-27T13:14:20+00:00 URL: https://externals.io/message/94276#94277 · In reply to: #94276 Am 27.06.16 um 15:01 schrieb Karl Pflästerer: > interface I1 { const C1 = '';} > class C3 implements I1 { const C1 = 'c2';} > $c3 = new C3; > var_dump($c3::C1); According to https://3v4l.org/jIcs6 it looks like that's intended behaviour ;) Cheers Andreas -- ,,, (o o) +---------------------------------------------------------ooO-(_)-Ooo-+ | Andreas Heigl | | mailto:andreas@heigl.org N 50°22'59.5" E 08°23'58" | | http://andreas.heigl.org http://hei.gl/wiFKy7 | +---------------------------------------------------------------------+ | http://hei.gl/root-ca | +---------------------------------------------------------------------+ --- ## #94278 — k@rl.pflaesterer.de — 2016-06-27T13:28:30+00:00 URL: https://externals.io/message/94276#94278 · In reply to: #94277 Andreas Heigl writes: > Am 27.06.16 um 15:01 schrieb Karl Pflästerer: > > […] > > According to https://3v4l.org/jIcs6 it looks like that's intended > behaviour ;) But why does it work in the CLI if I write the code (instead of using a script)? That's my question. KP --- ## #94281 — Christoph Becker — 2016-06-27T15:04:01+00:00 URL: https://externals.io/message/94276#94281 · In reply to: #94278 > Andreas Heigl writes: > > > […] > > But why does it work in the CLI if I write the code (instead of using a > script)? That's my question. Have you tried with and without OPcache? -- Christoph M. Becker --- ## #94280 — k@rl.pflaesterer.de — 2016-06-27T15:19:13+00:00 URL: https://externals.io/message/94276#94280 · In reply to: #94281 Am 27.06.16 um 17:04 schrieb Christoph Becker: > > > > […] > > Have you tried with and without OPcache? > There is no opcache in use. (Don't know if the message can be seen on the list; I only could read it in my mailbox; I could'nt see it in Gmane). KP --- ## #94282 — Andreas Heigl — 2016-06-27T15:31:44+00:00 URL: https://externals.io/message/94276#94282 · In reply to: #94278 Am 27.06.16 um 15:28 schrieb Karl Pflästerer: > Andreas Heigl writes: > > > […] > > But why does it work in the CLI if I write the code (instead of using a > script)? That's my question. It doesn't. At least not on my machine. This is the output I get: $ php -v PHP 7.1.0alpha2 (cli) (built: Jun 24 2016 13:50:28) ( NTS ) Copyright (c) 1997-2016 The PHP Group Zend Engine v3.1.0-dev, Copyright (c) 1998-2016 Zend Technologies $ php -a Interactive shell php > interface I1 { const C1 = '';} php > class C3 implements I1 { const C1 = 'c2';} PHP Fatal error: Cannot inherit previously-inherited or override constant C1 from interface I1 in php shell code on line 1 Fatal error: Cannot inherit previously-inherited or override constant C1 from interface I1 in php shell code on line 1 php > $c3 = new C3; php > var_dump($c3::C1); string(2) "c2" php > So it crashes with a fatal error when Implementing the interface. It'S interesting though that the script allows me to instantiate the class nonetheless. That's right. Perhaps some C-Guru can shed some light here? Cheers Andreas -- ,,, (o o) +---------------------------------------------------------ooO-(_)-Ooo-+ | Andreas Heigl | | mailto:andreas@heigl.org N 50°22'59.5" E 08°23'58" | | http://andreas.heigl.org http://hei.gl/wiFKy7 | +---------------------------------------------------------------------+ | http://hei.gl/root-ca | +---------------------------------------------------------------------+ --- ## #94283 — Bishop Bettini — 2016-06-27T15:41:10+00:00 URL: https://externals.io/message/94276#94283 · In reply to: #94282 > Am 27.06.16 um 15:28 schrieb Karl Pflästerer: > > […] > > It doesn't. At least not on my machine. This is the output I get: > > $ php -v > PHP 7.1.0alpha2 (cli) (built: Jun 24 2016 13:50:28) ( NTS ) > Copyright (c) 1997-2016 The PHP Group > Zend Engine v3.1.0-dev, Copyright (c) 1998-2016 Zend Technologies > Technically, this is a different version than reported. Nonetheless, on the same version my REPL complains as well, I suspect because the original report misspelled the INI setting ("-ddispplay_errors=On", notice the double "p"): $ php -v PHP 7.0.7 (cli) (built: May 28 2016 08:26:36) ( NTS ) Copyright (c) 1997-2016 The PHP Group Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies with Xdebug v2.4.0, Copyright (c) 2002-2016, by Derick Rethans $ php -a Interactive shell php > interface I1 { const C1 = ''; } php > class C3 implements I1 { const C1 = 'c2'; } PHP Fatal error: Cannot inherit previously-inherited or override constant C1 from interface I1 in php shell code on line 1 PHP Stack trace: PHP 1. {main}() php shell code:0 > So it crashes with a fatal error when Implementing the interface. It'S > interesting though that the script allows me to instantiate the class > nonetheless. That's right. > Under normal interpretive operation, the Fatal terminates the script. But in the case of the REPL command line, those are swallowed up and you can keep going. Same as like: php > foo(); PHP Warning: Uncaught Error: Call to undefined function foo() in php shell code:1 Stack trace: #0 {main} thrown in php shell code on line 1 PHP Stack trace: PHP 1. {main}() php shell code:0 php > echo 'hi'; hi I'm not seeing any bugs here. bishop --- ## #94285 — Rowan Collins — 2016-06-27T15:44:32+00:00 URL: https://externals.io/message/94276#94285 · In reply to: #94282 > So it crashes with a fatal error when Implementing the interface. It'S > interesting though that the script allows me to instantiate the class > nonetheless. It sounds to me like the ability of the interactive shell to catch fatal errors and continue allows you to execute code with the engine in a bogus state. It's possible to do all sorts of wacky things that way: php > class Bogus implements NonExistent {} PHP Fatal error: Interface 'NonExistent' not found in php shell code on line 1 Fatal error: Interface 'NonExistent' not found in php shell code on line 1 php > $b = new Bogus; php > var_dump($b); object(Bogus)#1 (0) { } php > var_dump($b instanceOf NonExistent); bool(false) php > var_dump($b instanceOf Bogus); bool(true) > PHP Fatal error: Cannot inherit previously-inherited or override > constant C1 from interface I1 in Can I just say this is a positively hideous error message. I can't actually figure out how to parse its grammar: is it (inherit previously-inherited) OR (override)? If so, what does "inherit previously-inherited" mean? --- ## #94284 — Andreas Heigl — 2016-06-27T15:46:49+00:00 URL: https://externals.io/message/94276#94284 · In reply to: #94283 Am 27.06.16 um 17:41 schrieb Bishop Bettini: > > > > […] > > Technically, this is a different version than reported. Nonetheless, on the > same version my REPL complains as well, I suspect because the original > report misspelled the INI setting ("-ddispplay_errors=On", notice the > double "p"): > > $ php -v > PHP 7.0.7 (cli) (built: May 28 2016 08:26:36) ( NTS ) > Copyright (c) 1997-2016 The PHP Group > Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies > with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend > Technologies > with Xdebug v2.4.0, Copyright (c) 2002-2016, by Derick Rethans > > $ php -a > Interactive shell > > php > interface I1 { const C1 = ''; } > php > class C3 implements I1 { const C1 = 'c2'; } > PHP Fatal error: Cannot inherit previously-inherited or override constant > C1 from interface I1 in php shell code on line 1 > PHP Stack trace: > PHP 1. {main}() php shell code:0 > > > > > […] > > Under normal interpretive operation, the Fatal terminates the script. But > in the case of the REPL command line, those are swallowed up and you can > keep going. Same as like: > > php > foo(); > PHP Warning: Uncaught Error: Call to undefined function foo() in php shell > code:1 > Stack trace: > #0 {main} > thrown in php shell code on line 1 > PHP Stack trace: > PHP 1. {main}() php shell code:0 > php > echo 'hi'; > hi > > I'm not seeing any bugs here. Thanks for the info. What I find strange is that I can instantiate the class "C3" even though the declaration of the class is broken. I wouldn't say it's a bug, but interesting. Cheers Andreas -- ,,, (o o) +---------------------------------------------------------ooO-(_)-Ooo-+ | Andreas Heigl | | mailto:andreas@heigl.org N 50°22'59.5" E 08°23'58" | | http://andreas.heigl.org http://hei.gl/wiFKy7 | +---------------------------------------------------------------------+ | http://hei.gl/root-ca | +---------------------------------------------------------------------+ --- ## #94286 — Bishop Bettini — 2016-06-27T15:55:00+00:00 URL: https://externals.io/message/94276#94286 · In reply to: #94285 On Mon, Jun 27, 2016 at 11:44 AM, Rowan Collins wrote: > > PHP Fatal error: Cannot inherit previously-inherited or override > > […] > > Can I just say this is a positively hideous error message. I can't > actually figure out how to parse its grammar: is it (inherit > previously-inherited) OR (override)? If so, what does "inherit > previously-inherited" mean? > > +1 on hideous. From this test , I believe "previously-inherited" refers to this situation: interface I1 { const BAR = 242; } interface I2 { const BAR = 242; } class Foo implements I1, I2 { }; --- ## #94287 — k@rl.pflaesterer.de — 2016-06-27T16:29:46+00:00 URL: https://externals.io/message/94276#94287 · In reply to: #94283 Bishop Bettini writes: > > > > […] > > Technically, this is a different version than reported. Nonetheless, on the > same version my REPL complains as well, I suspect because the original > report misspelled the INI setting ("-ddispplay_errors=On", notice the > double "p"): [...] Thanks; that explains why I didn't see the error message. > > Under normal interpretive operation, the Fatal terminates the script. But > in the case of the REPL command line, those are swallowed up and you can > keep going. Same as like: > And that explains why I was able to instantiate a broken class (with a overriden constant). So no bug but an interesting edge case. KP