perf: match a globstar-led glob on the last component, without a path copy

packages/python/e2e-attestations/bot-speed-walk-components-1011.json

@@ -0,0 +1,7 @@
+{
+  "command": "uv run python -m pytest tests/e2e/glob_speed_depth_bound_test.py tests/e2e/glob_speed_one_level_test.py tests/e2e/glob_speed_recursive_test.py tests/e2e/glob_speed_symlink_test.py tests/e2e/glob_speed_dotfiles_test.py tests/e2e/glob_speed_node_modules_test.py tests/e2e/glob_speed_matchers_test.py tests/e2e/glob_speed_gitignore_test.py tests/e2e/stat_speed_test.py tests/e2e/query_contract_test.py -x -q",
+  "ran_at": 1791771802,
+  "exit_code": 0,
+  "commit": "6a704d60f7963656097b921100e1f3aaefba6bbd",
+  "branch": "bot/speed-walk-components-1011"
+}

packages/rust/changelog.d/2026-10-11-faster-glob-matching.md

@@ -0,0 +1 @@
+**Changed** Matcher globs under `**` list sooner: a `**/`-led pattern is tested against the file name alone, and a path is no longer copied to be matched.

packages/rust/migrations.d/2026-10-11-faster-glob-matching.md

@@ -0,0 +1,21 @@
+### Faster glob matching
+
+#### Summary
+
+Glob matching under `**` copies fewer paths. Results and ordering are unchanged; nothing breaks.
+
+#### Required changes
+
+_None._
+
+#### Deprecations removed
+
+_None._
+
+#### Behavior changes without code changes
+
+_None._
+
+#### Verification
+
+Run `dirsql --help`; the CLI starts as before.

packages/rust/src/matcher.rs

@@ -17,25 +17,48 @@ pub enum GlobError {
 /// byte-oriented, so it is recompiled in Unicode mode over the `/`-separated
 /// path text.
 #[derive(Debug, Clone)]
-pub(crate) struct Pattern(Regex);
+pub(crate) struct Pattern {
+    path: Regex,
+    /// For a `**/`-led glob whose remainder is one component: that remainder,
+    /// which a path matches exactly when its last component does.
+    last_component: Option<Regex>,
+}
 
 impl Pattern {
     /// `*` and `?` stop at `/`; `**` crosses it.
     pub(crate) fn new(glob: &str) -> Result<Self, GlobError> {
-        let glob = GlobBuilder::new(&expand_posix_classes(glob))
-            .literal_separator(true)
-            .build()?;
-        let regex = RegexBuilder::new(&unicode_regex(glob.regex()))
-            .dot_matches_new_line(true)
-            .build()?;
-        Ok(Self(regex))
+        let last_component = match glob.strip_prefix("**/") {
+            Some(rest) if !rest.is_empty() && !rest.contains('/') => Some(compile(rest)?),
+            _ => None,
+        };
+        Ok(Self {
+            path: compile(glob)?,
+            last_component,
+        })
     }
 
     pub(crate) fn is_match(&self, path: &Path) -> bool {
-        self.0.is_match(&crate::scanner::to_slash(path))
+        if let Some((regex, name)) = self.last_component.as_ref().zip(path.file_name()) {
+            return regex.is_match(&name.to_string_lossy());
+        }
+        self.path.is_match(&crate::scanner::slashed(path))
+    }
+
+    #[cfg(test)]
+    pub(crate) fn matches_last_component_only(&self) -> bool {
+        self.last_component.is_some()
     }
 }
 
+fn compile(glob: &str) -> Result<Regex, GlobError> {
+    let glob = GlobBuilder::new(&expand_posix_classes(glob))
+        .literal_separator(true)
+        .build()?;
+    Ok(RegexBuilder::new(&unicode_regex(glob.regex()))
+        .dot_matches_new_line(true)
+        .build()?)
+}
+
 /// globset spells each non-ASCII character as the `\xNN` escapes of its UTF-8
 /// bytes, which in Unicode mode would name code points instead; decode each
 /// run back into the characters it encodes.
@@ -193,6 +216,44 @@ mod tests {
             .collect()
     }
 
+    #[test]
+    fn a_globstar_led_single_component_glob_matches_on_the_last_component_only() {
+        assert!(
+            Pattern::new("**/*.md")
+                .unwrap()
+                .matches_last_component_only()
+        );
+        assert!(
+            Pattern::new("**/{a,b}*.md")
+                .unwrap()
+                .matches_last_component_only()
+        );
+    }
+
+    #[test]
+    fn a_glob_with_a_directory_part_matches_the_whole_path() {
+        assert!(
+            !Pattern::new("a/**/*.md")
+                .unwrap()
+                .matches_last_component_only()
+        );
+        assert!(
+            !Pattern::new("**/a/*.md")
+                .unwrap()
+                .matches_last_component_only()
+        );
+        assert!(!Pattern::new("*.md").unwrap().matches_last_component_only());
+    }
+
+    #[test]
+    fn a_last_component_pattern_matches_at_any_depth_including_the_top() {
+        let pattern = Pattern::new("**/[[:digit:]]*.md").unwrap();
+        assert!(pattern.is_match(Path::new("1a.md")));
+        assert!(pattern.is_match(Path::new("x/.y/2b.md")));
+        assert!(!pattern.is_match(Path::new("1/b.md")));
+        assert!(!pattern.is_match(Path::new("1a.md/b.txt")));
+    }
+
     #[test]
     fn match_all_returns_table_for_matching_glob() {
         let matcher = TableMatcher::new(&[("*.csv", "data")], &[]).unwrap();

packages/rust/src/scanner.rs

@@ -3,6 +3,7 @@ use crate::matcher::{GlobError, Pattern, TableMatcher};
 use crate::tree_walk::{Step, walk_in_order};
 use ignore::Match;
 use ignore::gitignore::{Gitignore, GitignoreBuilder};
+use std::borrow::Cow;
 use std::ffi::OsStr;
 use std::fs;
 use std::path::{Path, PathBuf};
@@ -15,6 +16,14 @@ pub(crate) fn to_slash(path: &Path) -> String {
     with_slashes(&path.to_string_lossy(), std::path::MAIN_SEPARATOR)
 }
 
+pub(crate) fn slashed(path: &Path) -> Cow<'_, str> {
+    let text = path.to_string_lossy();
+    if std::path::MAIN_SEPARATOR == '/' {
+        return text;
+    }
+    Cow::Owned(with_slashes(&text, std::path::MAIN_SEPARATOR))
+}
+
 fn with_slashes(path: &str, native: char) -> String {
     if native == '/' {
         return path.to_owned();
@@ -1222,6 +1231,15 @@ mod tests {
         assert_eq!(with_slashes(r"dir/a\b.txt", '/'), r"dir/a\b.txt");
     }
 
+    #[cfg(unix)]
+    #[test]
+    fn slashed_borrows_a_native_unix_path() {
+        assert!(matches!(
+            slashed(Path::new("docs/nested/a.md")),
+            Cow::Borrowed("docs/nested/a.md")
+        ));
+    }
+
     #[test]
     fn to_slash_keeps_a_native_unix_path() {
         assert_eq!(to_slash(Path::new("docs/nested/a.md")), "docs/nested/a.md");

packages/ts/e2e-attestations/bot-speed-walk-components-1011.json

@@ -0,0 +1,7 @@
+{
+  "command": "pnpm test:e2e",
+  "ran_at": 1791771870,
+  "exit_code": 0,
+  "commit": "d8c9441c314abcf613ba761c0d84ffa5b953d6d6",
+  "branch": "bot/speed-walk-components-1011"
+}