--ignore-contain: ignore directories containing a named entry (e.g. [CACHEDIR.TAG](https://bford.info/cachedir/)).

Fixes #1727.

CHANGELOG.md

@@ -1,7 +1,7 @@
 # Upcoming release
 
 ## Features
-
+- Add `--ignore-contain` option to ignore directories containing a named entry (e.g. to ignore [`CACHEDIR.TAG`](https://bford.info/cachedir/)); see #1727 (@fischman).
 
 ## Bugfixes
 

src/cli.rs

@@ -528,6 +528,16 @@ pub struct Opts {
     )]
     pub hyperlink: HyperlinkWhen,
 
+    /// Ignore directories containing the named entry.
+    #[arg(
+        long,
+        value_name = "name",
+        hide_short_help = true,
+        help = "Ignore directories containing this name",
+        long_help
+    )]
+    pub ignore_contain: Option<String>,
+
     /// Set number of threads to use for searching & executing (default: number
     /// of available CPU cores)
     #[arg(long, short = 'j', value_name = "num", hide_short_help = true, value_parser = str::parse::<NonZeroUsize>)]

src/config.rs

@@ -130,6 +130,9 @@ pub struct Config {
 
     /// Whether or not to use hyperlinks on paths
     pub hyperlink: bool,
+
+    /// A name that should stop traversal down its parent. (e.g. https://bford.info/cachedir/).
+    pub ignore_contain: Option<String>,
 }
 
 impl Config {

src/main.rs

@@ -326,6 +326,7 @@ fn construct_config(mut opts: Opts, pattern_regexps: &[String]) -> Result<Config
         actual_path_separator,
         max_results: opts.max_results(),
         strip_cwd_prefix: opts.strip_cwd_prefix(|| !(opts.null_separator || has_command)),
+        ignore_contain: opts.ignore_contain,
     })
 }
 

src/walk.rs

@@ -560,6 +560,14 @@ impl WorkerState {
                     }
                 }
 
+                // Filter out directories containing a given name.
+                if let Some(ref ignore_contain) = config.ignore_contain
+                    && entry_path.is_dir()
+                    && entry_path.join(ignore_contain).exists()
+                {
+                    return WalkState::Skip;
+                }
+
                 // Filter out unwanted sizes if it is a file and we have been given size constraints.
                 if !config.size_constraints.is_empty() {
                     if entry_path.is_file() {

tests/tests.rs

@@ -2707,3 +2707,21 @@ fn test_hyperlink() {
 
     te.assert_output(&["--hyperlink=always", "a.foo"], &expected);
 }
+
+#[test]
+fn test_ignore_contain() {
+    let te = TestEnv::new(
+        &["include", "exclude", "exclude/sub"],
+        &[
+            "top",
+            "include/foo",
+            "exclude/CACHEDIR.TAG",
+            "exclude/sub/nope",
+        ],
+    );
+    let expected = "include/
+    include/foo
+    symlink
+    top";
+    te.assert_output(&["--ignore-contain=CACHEDIR.TAG", "."], expected);
+}