refactor(preg): split the PREG_UNMATCHED_AS_NULL preg_* by flag

preg_match2() and preg_match_all_offset_capture() each become a pair over
a shared private impl, and their flags arguments are gone: no caller passed
anything but 0 or PREG_UNMATCHED_AS_NULL. Preg::match5()/is_match5() lose
their own flags argument for the same reason -- both call sites passed 0,
and the value had nowhere left to go -- so they are renumbered to
match4()/is_match4(). PREG_UNMATCHED_AS_NULL itself is now unreferenced.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/crates/shirabe-class-map-generator/src/php_file_cleaner.rs b/crates/shirabe-class-map-generator/src/php_file_cleaner.rs
index eb2b84e4..c5952389 100644
--- a/crates/shirabe-class-map-generator/src/php_file_cleaner.rs
+++ b/crates/shirabe-class-map-generator/src/php_file_cleaner.rs
@@ -145,11 +145,10 @@ impl PhpFileCleaner {
                         if end <= self.len && self.contents[self.index..end] == entry.name {
                             let offset = if self.index > 0 { self.index - 1 } else { 0 };
                             let mut r#match: IndexMap<CaptureKey, String> = IndexMap::new();
-                            if Preg::is_match5(
+                            if Preg::is_match4(
                                 &entry.pattern,
                                 &self.contents,
                                 Some(&mut r#match),
-                                0,
                                 offset,
                             ) {
                                 return clean
@@ -294,6 +293,6 @@ impl PhpFileCleaner {
     }
 
     fn r#match(&self, regex: &str, r#match: Option<&mut IndexMap<CaptureKey, String>>) -> bool {
-        Preg::is_match5(regex, &self.contents, r#match, 0, self.index)
+        Preg::is_match4(regex, &self.contents, r#match, self.index)
     }
 }