ignore: fix gitignore parsing bug for trailing \/

When a glob pattern ended with a \/, and since we permit backslash
escapes, the glob parser gave a "dangling escape" error. Which is weird,
because the \ is clearly not dangling.

The issue is that the layer above the glob parser, the gitignore parser,
was stripping the trailing / so that it wouldn't be part of the matching
logic. Of course, stripping the trailing / while it is escaped without
removing the backslash escape is wrong. So we do that here.

Fixes #2236

1 files changed, 7 insertions, 4 deletions

diff --git a/crates/ignore/src/gitignore.rs b/crates/ignore/src/gitignore.rs
index 7922651c..3c7ba5e6 100644
--- a/crates/ignore/src/gitignore.rs
+++ b/crates/ignore/src/gitignore.rs
@@ -474,10 +474,13 @@ impl GitignoreBuilder {
         }
         // If it ends with a slash, then this should only match directories,
         // but the slash should otherwise not be used while globbing.
-        if let Some((i, c)) = line.char_indices().rev().nth(0) {
-            if c == '/' {
-                glob.is_only_dir = true;
-                line = &line[..i];
+        if line.as_bytes().last() == Some(&b'/') {
+            glob.is_only_dir = true;
+            line = &line[..line.len() - 1];
+            // If the slash was escaped, then remove the escape.
+            // See: https://github.com/BurntSushi/ripgrep/issues/2236
+            if line.as_bytes().last() == Some(&b'\\') {
+                line = &line[..line.len() - 1];
             }
         }
         glob.actual = line.to_string();