vim-patch:partial:9.2.0736: potential command execution in PHP omni-completion (#40445)

Problem:  With PHP omni-completion, a crafted file can potentially
          execute arbitrary commands when completing a class member.
Solution: Quote the class name before inserting it into the search()
          pattern run via win_execute().

43afc581a3

Tests only. The bug is not ported yet.

Co-authored-by: Hirohito Higashi <h.east.727@gmail.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/old/testdir/test_plugin_phpcomplete.vim

@@ -0,0 +1,35 @@
+" Tests for the PHP omni-completion plugin (runtime/autoload/phpcomplete.vim).
+
+" A buffer class name is interpolated into a search() pattern run via
+" win_execute().  Without escaping, "'" closes the string and "|" starts a new
+" Ex command, so the name runs as an Ex command during completion.
+func Test_phpcomplete_no_exec_via_class_name()
+  unlet! g:phpcomplete_injected
+  let lines = ['<?php', 'class x {}', '']
+  let payload = "x')|let g:phpcomplete_injected = 1|call search('"
+
+  try
+    call phpcomplete#GetClassContentsStructure('x.php', lines, payload)
+  catch
+  endtry
+
+  call assert_false(exists('g:phpcomplete_injected'),
+        \ 'class name was executed as an Ex command during completion')
+
+  unlet! g:phpcomplete_injected
+endfunc
+
+func Test_phpcomplete_class_lookup_still_works()
+  let lines = ['<?php', 'class Foo {', '    public $bar;', '}', '']
+  let result = phpcomplete#GetClassContentsStructure('Foo.php', lines, 'Foo')
+
+  call assert_equal(type([]), type(result),
+        \ 'GetClassContentsStructure did not return a list')
+  call assert_true(len(result) > 0, 'no class structure returned')
+  call assert_match('class Foo', result[0].content,
+        \ 'class body missing from returned content')
+  call assert_match('bar', result[0].content,
+        \ 'class member missing from returned content')
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab