refactor(pcre): treat regex compile failure as fatal in shim

The preg_* shim helpers wrapped their results in Option/Result solely to
signal a regex that failed to compile. Composer never feeds a pattern
that fails at runtime, so such a failure is a programming error: panic
instead and drop the Option/Result wrappers, updating all callers.

preg_replace_callback keeps its Result return type since the callback
itself is fallible. preg_match_groups is removed in favor of preg_match
at its sole call site.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

9 files changed, 63 insertions, 99 deletions

diff --git a/crates/shirabe-external-packages/src/composer/pcre/preg.rs b/crates/shirabe-external-packages/src/composer/pcre/preg.rs
index f72835d..d35a3aa 100644
--- a/crates/shirabe-external-packages/src/composer/pcre/preg.rs
+++ b/crates/shirabe-external-packages/src/composer/pcre/preg.rs
@@ -44,8 +44,7 @@ impl Preg {
             Some(&mut internal),
             flags | PREG_UNMATCHED_AS_NULL,
             offset,
-        )
-        .unwrap_or_else(|| invalid_regex());
+        );
 
         if let Some(out) = matches {
             *out = drop_null_matches(internal);
@@ -83,8 +82,7 @@ impl Preg {
             Some(&mut internal),
             flags | PREG_UNMATCHED_AS_NULL,
             offset,
-        )
-        .unwrap_or_else(|| invalid_regex());
+        );
 
         if let Some(out) = matches {
             *out = null_to_empty_match_all(internal);
@@ -109,8 +107,7 @@ impl Preg {
             Some(&mut internal),
             flags | PREG_UNMATCHED_AS_NULL | PREG_OFFSET_CAPTURE,
             offset,
-        )
-        .unwrap_or_else(|| invalid_regex());
+        );
 
         if let Some(out) = matches {
             *out = null_to_empty_offset_match_all(internal);
@@ -148,7 +145,6 @@ impl Preg {
         // guards (ARRAY_MSG / INVALID_TYPE_MSG) of the PHP original are
         // unreachable and not reproduced.
         shirabe_php_shim::preg_replace2(pattern, replacement, subject, limit, count)
-            .unwrap_or_else(|| invalid_regex())
     }
 
     pub fn replace_callback<F: FnMut(&IndexMap<CaptureKey, String>) -> String>(
@@ -172,7 +168,6 @@ impl Preg {
         };
 
         shirabe_php_shim::preg_replace_callback2(pattern, adapter, subject, limit, count, flags)
-            .unwrap_or_else(|| invalid_regex())
     }
 
     pub fn split(pattern: &str, subject: &str) -> Vec<String> {
@@ -186,7 +181,6 @@ impl Preg {
         );
 
         shirabe_php_shim::preg_split2(pattern, subject, limit, flags)
-            .unwrap_or_else(|| invalid_regex())
     }
 
     pub fn grep(pattern: &str, array: &[&str]) -> Vec<String> {
@@ -194,7 +188,7 @@ impl Preg {
     }
 
     pub fn grep3(pattern: &str, array: &[&str], flags: i64) -> Vec<String> {
-        shirabe_php_shim::preg_grep2(pattern, array, flags).unwrap_or_else(|| invalid_regex())
+        shirabe_php_shim::preg_grep2(pattern, array, flags)
     }
 
     pub fn is_match(pattern: &str, subject: &str) -> bool {
@@ -231,8 +225,7 @@ impl Preg {
             Some(&mut internal),
             PREG_UNMATCHED_AS_NULL,
             0,
-        )
-        .unwrap_or_else(|| invalid_regex());
+        );
 
         matches.clear();
         for (key, value) in internal {
@@ -248,8 +241,7 @@ impl Preg {
         // Classic preg_match semantics (no PREG_UNMATCHED_AS_NULL): trailing
         // unmatched groups are truncated, interior unmatched groups become "".
         let mut internal: IndexMap<CaptureKey, Option<String>> = IndexMap::new();
-        let result = shirabe_php_shim::preg_match2(pattern, subject, Some(&mut internal), 0, 0)
-            .unwrap_or_else(|| invalid_regex());
+        let result = shirabe_php_shim::preg_match2(pattern, subject, Some(&mut internal), 0, 0);
 
         if result == 0 {
             return None;
@@ -363,9 +355,3 @@ fn null_to_empty_offset_match_all(
         })
         .collect()
 }
-
-/// Panics if a pattern is invalid instead of throwing a PcreException.
-/// TODO: takes regex::Error and shows its message
-fn invalid_regex() -> ! {
-    panic!("invalid regex");
-}
diff --git a/crates/shirabe-external-packages/src/symfony/console/formatter/output_formatter.rs b/crates/shirabe-external-packages/src/symfony/console/formatter/output_formatter.rs
index 0de90be..6736ada 100644
--- a/crates/shirabe-external-packages/src/symfony/console/formatter/output_formatter.rs
+++ b/crates/shirabe-external-packages/src/symfony/console/formatter/output_formatter.rs
@@ -19,8 +19,7 @@ pub struct OutputFormatter {
 impl OutputFormatter {
     /// Escapes "<" and ">" special chars in given text.
     pub fn escape(text: &str) -> anyhow::Result<String> {
-        let text = shirabe_php_shim::preg_replace("/([^\\\\]|^)([<>])/", "$1\\\\$2", text)
-            .expect("preg_replace failed");
+        let text = shirabe_php_shim::preg_replace("/([^\\\\]|^)([<>])/", "$1\\\\$2", text);
 
         Ok(Self::escape_trailing_backslash(&text))
     }
@@ -106,7 +105,7 @@ impl OutputFormatter {
             "/([^=]+)=([^;]+)(;|$)/",
             string,
             &mut matches,
-        )? == 0
+        ) == 0
         {
             return Ok(None);
         }
@@ -122,8 +121,7 @@ impl OutputFormatter {
             } else if r#match[0] == "bg" {
                 style.set_background(Some(&shirabe_php_shim::strtolower(&r#match[1])));
             } else if r#match[0] == "href" {
-                let url = shirabe_php_shim::preg_replace("{\\\\([<>])}", "$1", &r#match[1])
-                    .expect("preg_replace failed");
+                let url = shirabe_php_shim::preg_replace("{\\\\([<>])}", "$1", &r#match[1]);
                 style.set_href(&url);
             } else if r#match[0] == "options" {
                 let mut options = shirabe_php_shim::preg_match_all(
@@ -292,7 +290,7 @@ impl WrappableOutputFormatterInterface for OutputFormatter {
             &format!("#<(({open_tag_regex}) | /({close_tag_regex})?)>#ix"),
             message,
             &mut matches,
-        )?;
+        );
         let count = matches.group(0).len();
         for i in 0..count {
             let (text, pos) = matches.group(0)[i].clone();
diff --git a/crates/shirabe-external-packages/src/symfony/console/helper/helper.rs b/crates/shirabe-external-packages/src/symfony/console/helper/helper.rs
index 40a8f85..07b1f77 100644
--- a/crates/shirabe-external-packages/src/symfony/console/helper/helper.rs
+++ b/crates/shirabe-external-packages/src/symfony/console/helper/helper.rs
@@ -147,12 +147,10 @@ impl Helper {
         // remove <...> formatting
         let string = formatter.format(Some(string)).unwrap().unwrap_or_default();
         // remove already formatted characters
-        let string =
-            shirabe_php_shim::preg_replace("/\u{1b}\\[[^m]*m/", "", &string).unwrap_or_default();
+        let string = shirabe_php_shim::preg_replace("/\u{1b}\\[[^m]*m/", "", &string);
         // remove terminal hyperlinks
         let string =
-            shirabe_php_shim::preg_replace("/\u{1b}]8;[^;]*;[^\u{1b}]*\u{1b}\\\\/", "", &string)
-                .unwrap_or_default();
+            shirabe_php_shim::preg_replace("/\u{1b}]8;[^;]*;[^\u{1b}]*\u{1b}\\\\/", "", &string);
         formatter.set_decorated(is_decorated);
 
         string
diff --git a/crates/shirabe-external-packages/src/symfony/console/input/argv_input.rs b/crates/shirabe-external-packages/src/symfony/console/input/argv_input.rs
index ea36e26..2b1102c 100644
--- a/crates/shirabe-external-packages/src/symfony/console/input/argv_input.rs
+++ b/crates/shirabe-external-packages/src/symfony/console/input/argv_input.rs
@@ -528,8 +528,13 @@ impl ArgvInput {
             .tokens
             .iter()
             .map(|token| {
-                if let Some(m) = shirabe_php_shim::preg_match_groups("{^(-[^=]+=)(.+)}", token) {
-                    return format!("{}{}", m[1], self.inner.escape_token(&m[2]));
+                let mut r#match: Vec<Option<String>> = Vec::new();
+                if shirabe_php_shim::preg_match("{^(-[^=]+=)(.+)}", token, &mut r#match) != 0 {
+                    return format!(
+                        "{}{}",
+                        r#match[1].as_deref().unwrap_or(""),
+                        self.inner.escape_token(r#match[2].as_deref().unwrap_or(""))
+                    );
                 }
 
                 if !token.is_empty() && token.as_bytes()[0] != b'-' {
diff --git a/crates/shirabe-external-packages/src/symfony/console/input/input_option.rs b/crates/shirabe-external-packages/src/symfony/console/input/input_option.rs
index 7e2d086..5ef265e 100644
--- a/crates/shirabe-external-packages/src/symfony/console/input/input_option.rs
+++ b/crates/shirabe-external-packages/src/symfony/console/input/input_option.rs
@@ -110,7 +110,7 @@ impl InputOption {
 
     fn normalize_shortcut(s: String) -> anyhow::Result<Option<String>> {
         let stripped = shirabe_php_shim::ltrim(&s, Some("-"));
-        let parts = shirabe_php_shim::preg_split(r"\|(-?)", &stripped).unwrap_or_default();
+        let parts = shirabe_php_shim::preg_split(r"\|(-?)", &stripped);
         let filtered: Vec<String> =
             shirabe_php_shim::array_filter(&parts, |s: &String| !s.is_empty());
         let result = shirabe_php_shim::implode("|", &filtered);
diff --git a/crates/shirabe-external-packages/src/symfony/console/input/string_input.rs b/crates/shirabe-external-packages/src/symfony/console/input/string_input.rs
index 952a18e..f57fcf6 100644
--- a/crates/shirabe-external-packages/src/symfony/console/input/string_input.rs
+++ b/crates/shirabe-external-packages/src/symfony/console/input/string_input.rs
@@ -56,7 +56,6 @@ impl StringInput {
 
             let mut m: IndexMap<CaptureKey, Option<String>> = IndexMap::new();
             if shirabe_php_shim::preg_match2(r"/\s+/A", input, Some(&mut m), 0, cursor as usize)
-                .expect("invalid regex")
                 == 1
             {
                 if token.is_some() {
@@ -70,9 +69,7 @@ impl StringInput {
                 Some(&mut m),
                 0,
                 cursor as usize,
-            )
-            .expect("invalid regex")
-                == 1
+            ) == 1
             {
                 let inner = shirabe_php_shim::substr(
                     m[&CaptureKey::ByIndex(3)].as_deref().unwrap_or(""),
@@ -96,9 +93,7 @@ impl StringInput {
                 Some(&mut m),
                 0,
                 cursor as usize,
-            )
-            .expect("invalid regex")
-                == 1
+            ) == 1
             {
                 token = Some(format!(
                     "{}{}",
@@ -117,9 +112,7 @@ impl StringInput {
                 Some(&mut m),
                 0,
                 cursor as usize,
-            )
-            .expect("invalid regex")
-                == 1
+            ) == 1
             {
                 token = Some(format!(
                     "{}{}",
diff --git a/crates/shirabe-php-shim/src/preg.rs b/crates/shirabe-php-shim/src/preg.rs
index 48b81ed..dc91fd6 100644
--- a/crates/shirabe-php-shim/src/preg.rs
+++ b/crates/shirabe-php-shim/src/preg.rs
@@ -56,13 +56,11 @@ pub fn preg_match(pattern: &str, subject: &str, matches: &mut Vec<Option<String>
     }
 }
 
-// Returns Some(result) on success, None on error.
-pub fn preg_replace(pattern: &str, replacement: &str, subject: &str) -> Option<String> {
+pub fn preg_replace(pattern: &str, replacement: &str, subject: &str) -> String {
     preg_replace2(pattern, replacement, subject, -1, None)
 }
 
-// Returns Some(parts) on success, None on error.
-pub fn preg_split(pattern: &str, subject: &str) -> Option<Vec<String>> {
+pub fn preg_split(pattern: &str, subject: &str) -> Vec<String> {
     preg_split2(pattern, subject, -1, 0)
 }
 
@@ -90,21 +88,15 @@ pub fn preg_match_all_set_order(
     pattern: &str,
     subject: &str,
     matches: &mut Vec<Vec<String>>,
-) -> anyhow::Result<i64> {
-    let re = compile_php_pattern(pattern)?;
+) -> i64 {
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let mut rows: Vec<Vec<String>> = Vec::new();
     for caps in re.captures_iter(subject) {
         rows.push(php_match_row(&caps));
     }
     let count = rows.len() as i64;
     *matches = rows;
-    Ok(count)
-}
-
-pub fn preg_match_groups(pattern: &str, subject: &str) -> Option<Vec<String>> {
-    let re = compile_php_pattern(pattern).ok()?;
-    let caps = re.captures(subject)?;
-    Some(php_match_row(&caps))
+    count
 }
 
 pub fn preg_grep(pattern: &str, input: &Vec<String>) -> Vec<String> {
@@ -116,8 +108,8 @@ pub fn preg_match_all_offset_capture(
     pattern: &str,
     subject: &str,
     matches: &mut PregOffsetCaptureMatches,
-) -> anyhow::Result<i64> {
-    let re = compile_php_pattern(pattern)?;
+) -> i64 {
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let group_count = re.captures_len();
     matches.groups = vec![Vec::new(); group_count];
 
@@ -136,7 +128,7 @@ pub fn preg_match_all_offset_capture(
         }
     }
 
-    Ok(count)
+    count
 }
 pub fn preg_replace_callback<F>(
     pattern: &str,
@@ -146,7 +138,7 @@ pub fn preg_replace_callback<F>(
 where
     F: FnMut(&[Option<String>]) -> anyhow::Result<String>,
 {
-    let re = compile_php_pattern(pattern)?;
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let mut out: Vec<u8> = Vec::new();
     let mut last = 0;
     for caps in re.captures_iter(subject) {
@@ -163,16 +155,15 @@ where
     Ok(String::from_utf8_lossy(&out).into_owned())
 }
 
-// Returns Some(0|1) on success or None when the underlying preg_match returned
-// false. Unmatched groups are reported as None (PREG_UNMATCHED_AS_NULL).
+// Returns 0|1. Unmatched groups are reported as None (PREG_UNMATCHED_AS_NULL).
 pub fn preg_match2(
     pattern: &str,
     subject: &str,
     matches: Option<&mut indexmap::IndexMap<CaptureKey, Option<String>>>,
     flags: i64,
     offset: usize,
-) -> Option<i64> {
-    let re = compile_php_pattern(pattern).ok()?;
+) -> i64 {
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let unmatched_as_null = flags & PREG_UNMATCHED_AS_NULL != 0;
     let caps = re.captures_at(subject, offset);
 
@@ -184,7 +175,7 @@ pub fn preg_match2(
         }
     }
 
-    Some(if caps.is_some() { 1 } else { 0 })
+    if caps.is_some() { 1 } else { 0 }
 }
 
 pub fn preg_match_all2(
@@ -193,8 +184,8 @@ pub fn preg_match_all2(
     matches: Option<&mut indexmap::IndexMap<CaptureKey, Vec<Option<String>>>>,
     flags: i64,
     offset: usize,
-) -> Option<i64> {
-    let re = compile_php_pattern(pattern).ok()?;
+) -> i64 {
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let unmatched_as_null = flags & PREG_UNMATCHED_AS_NULL != 0;
     let group_count = re.captures_len();
     let names: Vec<Option<&str>> = re.capture_names().collect();
@@ -224,7 +215,7 @@ pub fn preg_match_all2(
         }
     }
 
-    Some(count)
+    count
 }
 
 pub fn preg_match_all_offset_capture2(
@@ -233,8 +224,8 @@ pub fn preg_match_all_offset_capture2(
     matches: Option<&mut indexmap::IndexMap<CaptureKey, Vec<(Option<String>, i64)>>>,
     flags: i64,
     offset: usize,
-) -> Option<i64> {
-    let re = compile_php_pattern(pattern).ok()?;
+) -> i64 {
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let unmatched_as_null = flags & PREG_UNMATCHED_AS_NULL != 0;
     let group_count = re.captures_len();
     let names: Vec<Option<&str>> = re.capture_names().collect();
@@ -263,7 +254,7 @@ pub fn preg_match_all_offset_capture2(
         }
     }
 
-    Some(count)
+    count
 }
 
 pub fn preg_replace2(
@@ -272,8 +263,8 @@ pub fn preg_replace2(
     subject: &str,
     limit: i64,
     count: Option<&mut usize>,
-) -> Option<String> {
-    let re = compile_php_pattern(pattern).ok()?;
+) -> String {
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let limit = if limit < 0 {
         usize::MAX
     } else {
@@ -298,7 +289,7 @@ pub fn preg_replace2(
     if let Some(count) = count {
         *count = n;
     }
-    Some(String::from_utf8_lossy(&out).into_owned())
+    String::from_utf8_lossy(&out).into_owned()
 }
 
 pub fn preg_replace_callback2<
@@ -310,8 +301,8 @@ pub fn preg_replace_callback2<
     limit: i64,
     count: Option<&mut usize>,
     flags: i64,
-) -> Option<String> {
-    let re = compile_php_pattern(pattern).ok()?;
+) -> String {
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let unmatched_as_null = flags & PREG_UNMATCHED_AS_NULL != 0;
     let names: Vec<Option<&str>> = re.capture_names().collect();
     let limit = if limit < 0 {
@@ -339,11 +330,11 @@ pub fn preg_replace_callback2<
     if let Some(count) = count {
         *count = n;
     }
-    Some(String::from_utf8_lossy(&out).into_owned())
+    String::from_utf8_lossy(&out).into_owned()
 }
 
-pub fn preg_split2(pattern: &str, subject: &str, limit: i64, flags: i64) -> Option<Vec<String>> {
-    let re = compile_php_pattern(pattern).ok()?;
+pub fn preg_split2(pattern: &str, subject: &str, limit: i64, flags: i64) -> Vec<String> {
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let no_empty = flags & PREG_SPLIT_NO_EMPTY != 0;
     let delim_capture = flags & PREG_SPLIT_DELIM_CAPTURE != 0;
     // `limit` counts the resulting pieces; a non-positive value means no limit.
@@ -382,19 +373,17 @@ pub fn preg_split2(pattern: &str, subject: &str, limit: i64, flags: i64) -> Opti
     }
     push(&subject[last..], &mut result);
 
-    Some(result)
+    result
 }
 
-pub fn preg_grep2(pattern: &str, array: &[&str], flags: i64) -> Option<Vec<String>> {
-    let re = compile_php_pattern(pattern).ok()?;
+pub fn preg_grep2(pattern: &str, array: &[&str], flags: i64) -> Vec<String> {
+    let re = compile_php_pattern(pattern).unwrap_or_else(|e| panic!("invalid regex: {e}"));
     let invert = flags & PREG_GREP_INVERT != 0;
-    Some(
-        array
-            .iter()
-            .filter(|s| re.is_match(s) != invert)
-            .map(|s| s.to_string())
-            .collect(),
-    )
+    array
+        .iter()
+        .filter(|s| re.is_match(s) != invert)
+        .map(|s| s.to_string())
+        .collect()
 }
 
 // Translates a PHP PCRE pattern (delimiters + trailing modifiers) into a regex
diff --git a/crates/shirabe-semver/src/version_parser.rs b/crates/shirabe-semver/src/version_parser.rs
index bbd359e..bb4656c 100644
--- a/crates/shirabe-semver/src/version_parser.rs
+++ b/crates/shirabe-semver/src/version_parser.rs
@@ -25,7 +25,7 @@ pub struct VersionParser;
 
 impl VersionParser {
     pub fn parse_stability(version: &str) -> String {
-        let version = php::preg_replace("{#.+$}", "", version).unwrap_or_default();
+        let version = php::preg_replace("{#.+$}", "", version);
 
         if version.starts_with("dev-") || version.ends_with("-dev") {
             return "dev".to_string();
@@ -143,8 +143,7 @@ impl VersionParser {
                 MODIFIER_REGEX
             );
             if php::preg_match(&datetime_pattern, &version, &mut matches) > 0 {
-                version = php::preg_replace("{\\D}", ".", matches[1].as_deref().unwrap_or(""))
-                    .unwrap_or_default();
+                version = php::preg_replace("{\\D}", ".", matches[1].as_deref().unwrap_or(""));
                 index = Some(2);
             }
         }
@@ -297,8 +296,7 @@ impl VersionParser {
     pub fn parse_constraints(&self, constraints: &str) -> anyhow::Result<AnyConstraint> {
         let pretty_constraint = constraints.to_string();
 
-        let or_constraints = php::preg_split("{\\s*\\|\\|?\\s*}", &php::trim(constraints, None))
-            .ok_or_else(|| anyhow::anyhow!("Failed to preg_split string: {}", constraints))?;
+        let or_constraints = php::preg_split("{\\s*\\|\\|?\\s*}", &php::trim(constraints, None));
 
         let mut or_groups: Vec<AnyConstraint> = Vec::new();
 
@@ -306,8 +304,7 @@ impl VersionParser {
             let and_constraints = php::preg_split(
                 "{(?<!^|as|[=>< ,]) *(?<!-)[, ](?!-) *(?!,|as|$)}",
                 or_constraint,
-            )
-            .ok_or_else(|| anyhow::anyhow!("Failed to preg_split string: {}", or_constraint))?;
+            );
 
             let constraint_objects: Vec<AnyConstraint> = if and_constraints.len() > 1 {
                 let mut objs: Vec<AnyConstraint> = Vec::new();
diff --git a/crates/shirabe/src/console/application.rs b/crates/shirabe/src/console/application.rs
index 4be2f90..ad0073f 100644
--- a/crates/shirabe/src/console/application.rs
+++ b/crates/shirabe/src/console/application.rs
@@ -2711,9 +2711,7 @@ impl Application {
             Some(&mut m),
             0,
             offset as usize,
-        )
-        .expect("invalid regex")
-            == 1
+        ) == 1
         {
             let m0 = m[&shirabe_php_shim::CaptureKey::ByIndex(0)]
                 .as_deref()