Regression: grapheme_levenshtein() phantom on all profiles — Zend/php-src never ships it (ext/intl/grapheme)

[PurHur]

Category

Regression · php-src-strict · ext/intl grapheme · phantom builtin

Problem

function_exists('grapheme_levenshtein') is true on default / 8.2 / 8.3 / 8.4 / 8.5 profiles. Zend/php-src does not ship this function (ICU levenshtein RFC never landed; absent from ext/intl/grapheme/grapheme.stub.php on php-src master). Same class of phantom as mb_ucwords (#21458).

Verified 2026-07-23:

Profile	function_exists('grapheme_levenshtein')
default / 8.2 / 8.3 / 8.4 / 8.5	yes (wrong)
Zend 8.2 host	no
php-src grapheme.stub.php	no grapheme_levenshtein

Prior impl tracker: #6998 (closed) — should have stayed ungated/unregistered like Zend.

php-src reference

• php/php-src ext/intl/grapheme/grapheme.stub.php — no levenshtein
• php/php-src#10180 — multibyte levenshtein RFC (not accepted into stubs)

PHP implementation target

• ext/intl/Module.php — stop registering grapheme_levenshtein (or gate always-false like mb_ucwords / CompilerVersion advertisement)
• Keep ext/intl/grapheme_levenshtein.php / VmGrapheme::levenshtein only if useful internally; must not appear in function_exists / call tables
• PHP-in-PHP; no new C

Repro

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_grapheme_levenshtein_phantom.php'
PHP_COMPILER_PROFILE=8.4 php bin/vm.php test/repro/maintainer_gap_grapheme_levenshtein_phantom.php

<?php
echo function_exists('grapheme_levenshtein') ? "fail\n" : "ok\n";

Done when

• function_exists('grapheme_levenshtein') === false on every profile (match Zend)
• Compliance/phantom guard under test/compliance/cases/
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

claim: PHP Compiler STD Lib — starting this run

Gate probe (before claim):

• bootstrap-inventory --check: OK 6454/6454
• release-readiness --json: user_release_ready: no — first fail north-star5-fast step 4f-m (gen-0 manifest/driver mismatch Self-host M5: bootstrap-inventory argv driver size floor — grow beyond 451KB stub #8713 / Gen-1+ #1492: committed gen-0 seed cannot be rebuilt — refresh OOMs at 48 GiB, 44 restamps since the blob last changed (script/bootstrap-refresh-gen0-sidecar.sh) #22642 refresh OOM class)
• bootstrap-selfhost-link: in progress (stale gen-0 → Zend gen-0 fallback for compile)
• VM driver probe: ok (via release-readiness)

Pillar 1 partial (inventory/spine green; gen-0 sidecar stale on master). Proceeding with this stdlib phantom-removal (#22661) — not a gen-0 refresh run.

[PurHur]

Merged via #22677 (24ea5ef).

Verification

Gate	Result
VM default / 8.2 / 8.3 / 8.4 / 8.5	ok (function_exists false)
AOT default + PROFILE=8.4	ok (./phpc build + run)
./script/phpunit.sh --filter grapheme_levenshtein	OK (6 tests)
bootstrap-inventory --check	OK 6454/6454
check-generated-docs (Docker)	all in sync
release-readiness --json	user_release_ready: no — first fail north-star5-fast 4f-m gen-0 mismatch (master/#22642 class; unrelated to this phantom gate)

php-src-strict: matches ext/intl/grapheme/grapheme.stub.php (no grapheme_levenshtein). Same always-false gate shape as mb_ucwords (#21458).

[PurHur]

Merged via #22677 (24ea5ef).

Fix

• CompilerVersion::supportsGraphemeLevenshtein() / advertisesGraphemeLevenshtein() always false (same shape as mb_ucwords / Regression: mb_ucwords() phantom on PROFILE=8.4 — Zend 8.4/8.5 function_exists false (re-#20799, ext/mbstring) #21458)
• ext/intl/Module.php no longer registers the builtin
• Compliance phantom + forward-profile guards; internal VmGrapheme::levenshtein kept for unit tests

Verification

php bin/vm.php test/repro/maintainer_gap_grapheme_levenshtein_phantom.php   # ok
PHP_COMPILER_PROFILE=8.4 php bin/vm.php …                                   # ok
PHP_COMPILER_HELPER_RUNTIME_O=1 php bin/compile.php -o /tmp/glev_phantom … && /tmp/glev_phantom  # ok (AOT)
./script/phpunit.sh --filter grapheme_levenshtein                           # OK 6 tests
./script/check-generated-docs.sh                                            # OK

php-src-strict: matches absent grapheme.stub.php entry.

[PurHur]

Cleanup: dropping redundant test/repro/maintainer_gap_grapheme_levenshtein_phantom.php — covered by test/compliance/cases/stdlib/grapheme_levenshtein_forward_profile.phpt. See chore PR.