cli: add --no-require-git flag

This flag prevents ripgrep from requiring one to search a git repository
in order to respect git-related ignore rules (global, .gitignore and
local excludes). This actually corresponds to behavior ripgrep had long
ago, but #934 changed that. It turns out that users were relying on this
buggy behavior. In most cases, fixing it as simple as converting one's
rules to .ignore or .rgignore files. Unfortunately, there are other use
cases---like Perforce automatically respecting .gitignore files---that
make a strong case for ripgrep to at least support this.

The UX of a flag like this is absolutely atrocious. It's so obscure that
it's really not worth explicitly calling it out anywhere. Moreover, the
error cases that occur when this flag isn't used (but its behavior is
desirable) will not be intuitive, do not seem easily detectable and will
not guide users to this flag. Nevertheless, the motivation for this is
just barely strong enough for me to begrudgingly accept this.

Fixes #1414, Closes #1416

8 files changed, 100 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 95cf28d2..e72d48af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,8 @@ Feature enhancements:
   Add `--include-zero` flag that shows files searched without matches.
 * [FEATURE #1390](https://github.com/BurntSushi/ripgrep/pull/1390):
   Add `--no-context-separator` flag that always hides context separators.
+* [FEATURE #1414](https://github.com/BurntSushi/ripgrep/pull/1414):
+  Add `--no-require-git` flag to allow ripgrep to respect gitignores anywhere.
 * [FEATURE #1420](https://github.com/BurntSushi/ripgrep/pull/1420):
   Add `--no-ignore-exclude` to disregard rules in `.git/info/exclude` files.
 
diff --git a/ci/test_complete.sh b/ci/test_complete.sh
index 985ef11b..0268de89 100755
--- a/ci/test_complete.sh
+++ b/ci/test_complete.sh
@@ -44,7 +44,7 @@ main() {
     # Occasionally we may have to handle some manually, however
     help_args=( ${(f)"$(
         $rg --help |
-        $rg -i -- '^\s+--?[a-z0-9]|--[imnp]' |
+        $rg -i -- '^\s+--?[a-z0-9]|--[a-z]' |
         $rg -ior '$1' -- $'[\t /\"\'`.,](-[a-z0-9]|--[a-z0-9-]+)\\b' |
         $rg -v -- --print0 | # False positives
         sort -u
diff --git a/complete/_rg b/complete/_rg
index b90d1801..82dc3cdb 100644
--- a/complete/_rg
+++ b/complete/_rg
@@ -144,6 +144,8 @@ _rg() {
     + '(ignore-vcs)' # VCS ignore-file options
     "--no-ignore-vcs[don't respect version control ignore files]"
     $no'--ignore-vcs[respect version control ignore files]'
+    "--no-require-git[don't require git repository to respect gitignore rules]"
+    $no'--require-git[require git repository to respect gitignore rules]'
 
     + '(ignore-dot)' # .ignore-file options
     "--no-ignore-dot[don't respect .ignore files]"
@@ -284,6 +286,7 @@ _rg() {
     '--context-separator=[specify string used to separate non-continuous context lines in output]:separator'
     $no"--no-context-separator[don't print context separators]"
     '--debug[show debug messages]'
+    '--trace[show more verbose debug messages]'
     '--dfa-size-limit=[specify upper size limit of generated DFA]:DFA size (bytes)'
     "(1 stats)--files[show each file that would be searched (but don't search)]"
     '*--ignore-file=[specify additional ignore file]:ignore file:_files'
diff --git a/ignore/src/dir.rs b/ignore/src/dir.rs
index cf957891..3f4d10bb 100644
--- a/ignore/src/dir.rs
+++ b/ignore/src/dir.rs
@@ -78,6 +78,9 @@ struct IgnoreOptions {
     git_exclude: bool,
     /// Whether to ignore files case insensitively
     ignore_case_insensitive: bool,
+    /// Whether a git repository must be present in order to apply any
+    /// git-related ignore rules.
+    require_git: bool,
 }
 
 /// Ignore is a matcher useful for recursively walking one or more directories.
@@ -385,7 +388,9 @@ impl Ignore {
             Match::None,
             Match::None,
         );
-        let any_git = self.parents().any(|ig| ig.0.has_git);
+        let any_git =
+            !self.0.opts.require_git
+            || self.parents().any(|ig| ig.0.has_git);
         let mut saw_git = false;
         for ig in self.parents().take_while(|ig| !ig.0.is_absolute_parent) {
             if m_custom_ignore.is_none() {
@@ -537,6 +542,7 @@ impl IgnoreBuilder {
                 git_ignore: true,
                 git_exclude: true,
                 ignore_case_insensitive: false,
+                require_git: true,
             },
         }
     }
@@ -686,6 +692,16 @@ impl IgnoreBuilder {
         self
     }
 
+    /// Whether a git repository is required to apply git-related ignore
+    /// rules (global rules, .gitignore and local exclude rules).
+    ///
+    /// When disabled, git-related ignore rules are applied even when searching
+    /// outside a git repository.
+    pub fn require_git(&mut self, yes: bool) -> &mut IgnoreBuilder {
+        self.opts.require_git = yes;
+        self
+    }
+
     /// Process ignore files case insensitively
     ///
     /// This is disabled by default.
@@ -883,6 +899,21 @@ mod tests {
     }
 
     #[test]
+    fn gitignore_allowed_no_git() {
+        let td = tmpdir();
+        wfile(td.path().join(".gitignore"), "foo\n!bar");
+
+        let (ig, err) = IgnoreBuilder::new()
+            .require_git(false)
+            .build()
+            .add_child(td.path());
+        assert!(err.is_none());
+        assert!(ig.matched("foo", false).is_ignore());
+        assert!(ig.matched("bar", false).is_whitelist());
+        assert!(ig.matched("baz", false).is_none());
+    }
+
+    #[test]
     fn ignore() {
         let td = tmpdir();
         wfile(td.path().join(".ignore"), "foo\n!bar");
diff --git a/ignore/src/walk.rs b/ignore/src/walk.rs
index bbe6d7d7..331268a3 100644
--- a/ignore/src/walk.rs
+++ b/ignore/src/walk.rs
@@ -780,6 +780,16 @@ impl WalkBuilder {
         self
     }
 
+    /// Whether a git repository is required to apply git-related ignore
+    /// rules (global rules, .gitignore and local exclude rules).
+    ///
+    /// When disabled, git-related ignore rules are applied even when searching
+    /// outside a git repository.
+    pub fn require_git(&mut self, yes: bool) -> &mut WalkBuilder {
+        self.ig_builder.require_git(yes);
+        self
+    }
+
     /// Process ignore files case insensitively
     ///
     /// This is disabled by default.
diff --git a/src/app.rs b/src/app.rs
index 94e8a421..320261b5 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -602,6 +602,7 @@ pub fn all_args_and_flags() -> Vec<RGArg> {
     flag_no_ignore_vcs(&mut args);
     flag_no_messages(&mut args);
     flag_no_pcre2_unicode(&mut args);
+    flag_no_require_git(&mut args);
     flag_null(&mut args);
     flag_null_data(&mut args);
     flag_one_file_system(&mut args);
@@ -1928,6 +1929,28 @@ This flag can be disabled with --pcre2-unicode.
     args.push(arg);
 }
 
+fn flag_no_require_git(args: &mut Vec<RGArg>) {
+    const SHORT: &str = "Do not require a git repository to use gitignores.";
+    const LONG: &str = long!("\
+By default, ripgrep will only respect global gitignore rules, .gitignore rules
+and local exclude rules if ripgrep detects that you are searching inside a
+git repository. This flag allows you to relax this restriction such that
+ripgrep will respect all git related ignore rules regardless of whether you're
+searching in a git repository or not.
+
+This flag can be disabled with --require-git.
+");
+    let arg = RGArg::switch("no-require-git")
+        .help(SHORT).long_help(LONG)
+        .overrides("require-git");
+    args.push(arg);
+
+    let arg = RGArg::switch("require-git")
+        .hidden()
+        .overrides("no-require-git");
+    args.push(arg);
+}
+
 fn flag_null(args: &mut Vec<RGArg>) {
     const SHORT: &str = "Print a NUL byte after file paths.";
     const LONG: &str = long!("\
diff --git a/src/args.rs b/src/args.rs
index a322c55b..d9eeb2e1 100644
--- a/src/args.rs
+++ b/src/args.rs
@@ -882,6 +882,7 @@ impl ArgMatches {
             .git_global(!self.no_ignore_vcs() && !self.no_ignore_global())
             .git_ignore(!self.no_ignore_vcs())
             .git_exclude(!self.no_ignore_vcs() && !self.no_ignore_exclude())
+            .require_git(!self.is_present("no-require-git"))
             .ignore_case_insensitive(self.ignore_file_case_insensitive());
         if !self.no_ignore() {
             builder.add_custom_ignore_filename(".rgignore");
diff --git a/tests/feature.rs b/tests/feature.rs
index 33ab4e17..3d61f459 100644
--- a/tests/feature.rs
+++ b/tests/feature.rs
@@ -728,6 +728,34 @@ rgtest!(f1207_ignore_encoding, |dir: Dir, mut cmd: TestCommand| {
     eqnice!("\u{FFFD}\u{FFFD}\x00b\n", cmd.stdout());
 });
 
+// See: https://github.com/BurntSushi/ripgrep/issues/1414
+rgtest!(f1414_no_require_git, |dir: Dir, mut cmd: TestCommand| {
+    dir.create(".gitignore", "foo");
+    dir.create("foo", "");
+    dir.create("bar", "");
+
+    let stdout = cmd.args(&[
+        "--sort", "path",
+        "--files",
+    ]).stdout();
+    eqnice!("bar\nfoo\n", stdout);
+
+    let stdout = cmd.args(&[
+        "--sort", "path",
+        "--files",
+        "--no-require-git",
+    ]).stdout();
+    eqnice!("bar\n", stdout);
+
+    let stdout = cmd.args(&[
+        "--sort", "path",
+        "--files",
+        "--no-require-git",
+        "--require-git",
+    ]).stdout();
+    eqnice!("bar\nfoo\n", stdout);
+});
+
 // See: https://github.com/BurntSushi/ripgrep/pull/1420
 rgtest!(f1420_no_ignore_dot, |dir: Dir, mut cmd: TestCommand| {
     dir.create_dir(".git/info");