ignore: fix filtering searching subdir or .ignore in parent dir

The previous code deleted too many parts of the path when constructing the absolute path, resulting in a shortened final path. This patch creates the correct absolute path by only removing the necessary parts.

Fixes BurntSushi#2836

crates/ignore/src/dir.rs

@@ -461,21 +461,31 @@ impl Ignore {
                 // off of `path`. Overall, this seems a little ham-fisted, but
                 // it does fix a nasty bug. It should do fine until we overhaul
                 // this crate.
-                let dirpath = self.0.dir.as_path();
-                let path_prefix = match strip_prefix("./", dirpath) {
-                    None => dirpath,
-                    Some(stripped_dot_slash) => stripped_dot_slash,
-                };
-                let path = match strip_prefix(path_prefix, path) {
-                    None => abs_parent_path.join(path),
-                    Some(p) => {
-                        let p = match strip_prefix("/", p) {
-                            None => p,
-                            Some(p) => p,
-                        };
-                        abs_parent_path.join(p)
-                    }
-                };
+
+                fn strip_if_is_prefix<'a, P: AsRef<Path> + ?Sized>(
+                    prefix: &'a P,
+                    path: &'a Path,
+                ) -> &'a Path {
+                    strip_prefix(prefix, path).map_or(path, |p| p)
+                }
+
+                let path = abs_parent_path.join(
+                    self.parents()
+                        .take_while(|ig| !ig.0.is_absolute_parent)
+                        .last()
+                        .map_or(path, |ig| {
+                            strip_if_is_prefix(
+                                "/",
+                                strip_if_is_prefix(
+                                    strip_if_is_prefix(
+                                        "./",
+                                        ig.0.dir.as_path(),
+                                    ),
+                                    path,
+                                ),
+                            )
+                        }),
+                );
 
                 for ig in
                     self.parents().skip_while(|ig| !ig.0.is_absolute_parent)

tests/regression.rs

@@ -965,6 +965,15 @@ rgtest!(f1757, |dir: Dir, _: TestCommand| {
     eqnice!("rust/source.rs\n", dir.command().args(args).stdout());
     let args = &["--files-with-matches", "needle", "./rust"];
     eqnice!("./rust/source.rs\n", dir.command().args(args).stdout());
+
+    dir.create_dir("rust1/target/onemore");
+    dir.create(".ignore", "rust1/target/onemore");
+    dir.create("rust1/source.rs", "needle");
+    dir.create("rust1/target/onemore/rustdoc-output.html", "needle");
+    let args = &["--files-with-matches", "needle", "rust1"];
+    eqnice!("rust1/source.rs\n", dir.command().args(args).stdout());
+    let args = &["--files-with-matches", "needle", "./rust1"];
+    eqnice!("./rust1/source.rs\n", dir.command().args(args).stdout());
 });
 
 // See: https://github.com/BurntSushi/ripgrep/issues/1765
@@ -1217,3 +1226,13 @@ rgtest!(r2658_null_data_line_regexp, |dir: Dir, mut cmd: TestCommand| {
     let got = cmd.args(&["--null-data", "--line-regexp", r"bar"]).stdout();
     eqnice!("haystack:bar\0", got);
 });
+
+rgtest!(f2836, |dir: Dir, mut cmd: TestCommand| {
+    dir.create_dir("testdir/sub/sub2");
+    dir.create(".ignore", "/testdir/sub/sub2/");
+    dir.create("testdir/sub/sub2/testfile", "needle");
+
+    let args = &["--files-with-matches", "needle"];
+    cmd.current_dir(dir.path().join("testdir"));
+    cmd.args(args).assert_err();
+});