Update screens for output that changed with PHP itself

[KentarouTakeda]

Follow-up to #5718, from the same audit: the examples where PHP's own behaviour moved and the <screen> was never updated. One commit per kind of change.

• +/- vs . precedence (8.0), constants left of instanceof (7.3)
• reading a missing array key is a warning (8.0); the BackedEnum::from() ValueError no longer quotes the enum name (8.2)
• internal functions declare return types (8.0)
• anonymous class naming (8.0), var_export() leading backslash (8.2)
• mb_detect_encoding() non-strict detection (8.3)
• ReflectionClass::__toString() regenerated rather than attributed to one change; the Exception dump has drifted across several releases

Where a corrected screen would leave the page contradicting itself, the prose or comment moves with it: the foreach "notice" sentence, two comments in the precedence example, the mb_detect_encoding() comment, and the anonymous class note. The two reflection examples needed replacing outright — they used array_merge() to show that internals report no return type, which it now does, so a method with a tentative return type takes its place.

Pages to check with Run code

Press Run code and the output that appears is what this PR puts in the <screen>. The static one still on these pages is the "before" side of the diff, until the manual is rebuilt.

• https://www.php.net/manual/en/language.operators.precedence.php
• https://www.php.net/manual/en/language.operators.type.php
• https://www.php.net/manual/en/control-structures.foreach.php
• https://www.php.net/manual/en/backedenum.from.php
• https://www.php.net/manual/en/reflectionfunctionabstract.getreturntype.php
• https://www.php.net/manual/en/reflectionfunctionabstract.hasreturntype.php
• https://www.php.net/manual/en/reflectionclass.tostring.php
• https://www.php.net/manual/en/language.oop5.anonymous.php
• https://www.php.net/manual/en/language.oop5.magic.php
• https://www.php.net/manual/en/function.mb-detect-encoding.php

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P.S. — after the review on #5718, every example in this PR was re-run on 8.2, 8.3, 8.4 and 8.5 rather than trusted to Run code, which is one wasm build of one version.

That turned up one case: mb_detect_encoding()'s non-strict change landed in 8.3.0, so 8.2 still prints the old result and a single screen cannot cover both. Both examples on that page are now split with &example.outputs.82; / &example.outputs.83; — the basic example was already showing only the 8.3 behaviour, so it is split too rather than leaving one page inconsistent with itself.

Everything else agrees across 8.2–8.5, including the line numbers in the two Fatal error: screens and the ReflectionClass::__toString() dump of Exception.

[kamil-tekiela]

I have not looked at the rest of the changes in this PR yet. If the behaviour changed, then we need to maintain both outputs. In this case, the example is only applicable to PHP 7 (it looks like the output was incorrect even with PHP 7), but we need to keep the example until PHP 9 is released. So if you want to show that this behaviour changed in PHP 8, first you need to fix the example so that it makes sense for PHP 7, and then add a note that as of PHP 8, this has been fixed and is no longer an issue. You should not change the code comments as they are correct and point out the pitfall. The output should include the warnings too. There should also be a note about the deprecation in PHP 7.4.

The correct output:

Warning: A non-numeric value encountered in /in/mFYgu on line 4
-1, or so I hope
x minus one equals 3, or so I hope

Warning: A non-numeric value encountered in /in/mFYgu on line 10
-1, or so I hope

Although this warning has been there only since PHP 7.1.

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We could make the example represent the current state, but that would be incorrect in this case. We do not want to preserve this example going forward. It only exists to warn people of this historical quirk. So in my opinion, the most beneficial is to show what it was like between 7.1 and 7.4 and add a note for 7.4 and 8.0 changes.

[kamil-tekiela]

I just saw that there is another example underneath which shows what it was before. I don't think that's right. Both code blocks are the same. This needs to be merged as I said above.

[KentarouTakeda]

Merged — the current-behaviour example is gone, and this one keeps its original comments untouched.

The output includes the warnings now. Measured: 7.1, 7.2 and 7.3 all print the two A non-numeric value encountered warnings, and the screen that was here matched PHP 7.0 exactly, the one 7.x that doesn't warn. Hence &example.outputs.71; rather than &example.outputs.7;. The 7.4 deprecation is in a note below, as you asked.

One thing I did differently: the 8.0 change is a second screen rather than only a note, following your "if the behaviour changed, then we need to maintain both outputs". It also shows that the spelled-out grouping now throws, so the third line never runs. Say the word and it goes back to prose.

I kept annotations="non-interactive" on the example — Run code overwrites the first screen in place, caption included, so on a split example the older screen disappears on the first click. More on that in a comment on the PR.

[kamil-tekiela]

BTW are doing all of it with Claude? If so it would be nice if you gave it the proper attribution like in 0009ebd

[KentarouTakeda]

Yes. I'll add the trailer from here on — thanks for the pointer.

[kamil-tekiela]

Ok, but we need to retain the error message. Perhaps split it into two outputs per version? Or just add a code comment on var_dump(FALSE instanceof stdClass); saying it would throw with this error message?

[KentarouTakeda]

Took the code comment. A split would mislead here: prior to 7.3 this is a compile-time error, so 7.2 prints the fatal line and nothing else — none of the three bool(false) above it ever run. The screen that was here, three bools followed by the fatal error, was never any version's output.

That's why the comment says "so nothing above ran". The 7.3 boundary itself is already covered by the example directly below, which uses &example.outputs.73;.

[KentarouTakeda]

Following up on "if the behaviour changed, then we need to maintain both outputs" — since you hadn't looked at the rest of the PR yet, I went back over every hunk with one question: was the screen that was there an actual capture of a version the manual still covers? Every answer below is measured, not guessed.

Split, because there was a real output to keep

• foreach — the old screen matches 7.4 exactly, so it is now &example.outputs.71; plus &example.outputs.8;. Not &example.outputs.7;, because the short list syntax doesn't parse on 7.0.
• __set_state() — the old screen matches 8.1 exactly, so it is now &example.outputs.81; plus &example.outputs.82;.

Not split, because the old screen was no version's output

• ReflectionClass::__toString() — the old screen has ten methods and no __wakeup, so it predates 5.6. Nothing in the ten files this PR touches refers to anything older than 7.1, and a faithful PHP 5 screen would run to sixty lines.
• anonymous classes — 7.4 prints ["num":"class@anonymous":private], not the ["Command line code0x104c5b612":...] that was there. The 8.0 naming change is real, but there is no old output to preserve, and the note on that example already says the generated name must not be relied upon.
• BackedEnum::from() — the message quoting did change in 8.2, but the old screen also dropped the stack trace that every version prints, and had the line number wrong.

One thing worth knowing about the split pattern

Run code replaces the first screen in place, caption included (interactive-examples.js), and leaves later screens alone. On an example with two screens that destroys the older one on the first click — the very screen the split exists to preserve.

It is visible today on language.types.array.php: press Run code and the "PHP 8.0" screen becomes "PHP 8.5.0" carrying the 8.1 output, leaving two identical outputs under different labels. The markup there is fine; it is the runner that assumes one screen per example.

Every example I split in this PR is therefore marked annotations="non-interactive". I can send the same one-line change for array.xml, though the better fix may be in web-php: when an example has more than one screen, append the live output rather than overwrite, or target the screen whose caption matches the running version.