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Date: Thu, 22 Aug 2024 22:40:45 +0100
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Subject: Re: [PHP-DEV] [Concept] Flip relative function lookup order (global,
 then local)
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From: imsop.php@rwec.co.uk ("Rowan Tommins [IMSoP]")

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On 02/08/2024 23:00, Nick Lockheart wrote:
> If class A relies on class B, but you want to swap out
> class B with a stub to test class A in isolation,
> is there a way to make every call to class B,
> from class A, actually call a different class
> during the test, without modifying class A's code?


There are libraries that do exactly this, such as Mockery's "overload" 
and "alias"; and some that do other transparent manipulations, like 
https://github.com/dg/bypass-finals

They work by generating code dynamically, based on the real code, and 
executing it before the real definition is loaded. The same approach 
could definitely be taken to replace every call to a global function, 
and would actually be more reliable than shadowing, because it could 
rewrite even calls with a leading "\" or "use function" statement.

Obviously, shadowing a function in one namespace is currently a lot 
easier than setting up such a rewriter; but I don't think we should let 
that convenience for a few use cases outweigh the benefits in 
performance that a change in behaviour could bring, particularly when 
combined with function autoloading.

-- 
Rowan Tommins
[IMSoP]

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    <div class="moz-cite-prefix">On 02/08/2024 23:00, Nick Lockheart
      wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:cededcb399dccc64131fec1d19821ace42e5a761.camel@ageofdream.com">
      <pre>If class A relies on class B, but you want to swap out
class B with a stub to test class A in isolation,
is there a way to make every call to class B,
from class A, actually call a different class
during the test, without modifying class A's code?</pre>
    </blockquote>
    <p><br>
    </p>
    <p>There are libraries that do exactly this, such as Mockery's
      "overload" and "alias"; and some that do other transparent
      manipulations, like <a class="moz-txt-link-freetext" href="https://github.com/dg/bypass-finals">https://github.com/dg/bypass-finals</a></p>
    <p>They work by generating code dynamically, based on the real code,
      and executing it before the real definition is loaded. The same
      approach could definitely be taken to replace every call to a
      global function, and would actually be more reliable than
      shadowing, because it could rewrite even calls with a leading "\"
      or "use function" statement.</p>
    <p>Obviously, shadowing a function in one namespace is currently a
      lot easier than setting up such a rewriter; but I don't think we
      should let that convenience for a few use cases outweigh the
      benefits in performance that a change in behaviour could bring,
      particularly when combined with function autoloading.</p>
    <pre class="moz-signature" cols="72">-- 
Rowan Tommins
[IMSoP]</pre>
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