Custom ignore files can not be used exclusively

[sharkdp]

What version of the ignore crate are you using?

ignore-0.4.0

Describe your question, feature request, or bug.

It would be great if the custom ignore files (that are available since ignore-0.4.0) could be used exclusively without having to enable .ignore or .gitignore files as well.

If this is a bug, what are the steps to reproduce the behavior?

Run the following test case:

#[test]
fn custom_ignore() {
    let td = TempDir::new("walk-test-").unwrap();
    let custom_ignore = ".customignore";
    mkdirp(td.path().join("a"));
    wfile(td.path().join(custom_ignore), "foo");
    wfile(td.path().join("foo"), "");
    wfile(td.path().join("a/foo"), "");
    wfile(td.path().join("bar"), "");
    wfile(td.path().join("a/bar"), "");

    let mut builder = WalkBuilder::new(td.path());

    // THE FOLLOWING FOUR LINES HAVE BEEN
    // ADDED W.R.T. AN EXISTING TEST CASE
    builder.ignore(false);
    builder.git_ignore(false);
    builder.git_global(false);
    builder.git_exclude(false);

    builder.add_custom_ignore_filename(&custom_ignore);
    assert_paths(td.path(), &builder, &["bar", "a", "a/bar"]);
}

If this is a bug, what is the actual behavior?

The test case fails because the foo files are not ignored:

---- walk::tests::custom_ignore stdout ----
	thread 'walk::tests::custom_ignore' panicked at 'assertion failed: `(left == right)`
  left: `["a", "a/bar", "a/foo", "bar", "foo"]`,
 right: `["a", "a/bar", "bar"]`', src/walk.rs:1554:8

If this is a bug, what is the expected behavior?

The test case succeeds.

Analysis

The cause for this behavior is the following function in ignore/src/dir.rs:

    fn has_any_ignore_options(&self) -> bool {
        self.ignore || self.git_global || self.git_ignore || self.git_exclude
    }

.. which returns false if all of these are disabled. This, in turn, causes Ignore::matched to skip ignore files alltogether:

        if self.0.opts.has_any_ignore_options() {
            let mat = self.matched_ignore(path, is_dir);
            if mat.is_ignore() {
                return mat;
            } else if mat.is_whitelist() {
                whitelisted = mat;
            }
        }

If the above behavior is actually intended, a simple bugfix would be to add the following:

        if self.0.opts.has_any_ignore_options() || !self.0.custom_ignore_filenames.is_empty() {
            // ...
        }

[BurntSushi]

Thanks for the clear bug report! This definitely sounds like a bug, and has_any_ignore_options should probably be removed in favor of a predicate that covers all of the cases.

[sharkdp]

By the way, ripgrep itself is not "affected" (I think) because the custom ignore file (.rgignore) is always enabled together with .ignore. Therefore, IgnoreOptions::ignore will be enabled if .rgignore files should be used and has_any_ignore_options() returns true.

[BurntSushi]

@sharkdp Yup I believe you're right. Thanks for noticing this and filing a bug. :)