lib/git: add Git type with method IsIgnored

The Git type is for working with single git repository.

The [Git.IsIgnored] method is to check if the `path` is ignored by
git.
This is processed by matching it with all of the pattern in the
".gitignore" file from the path directory and its parent until the
root of Git repository.

4 files changed, 16 insertions, 0 deletions

diff --git a/lib/git/testdata/IsIgnored/.gitignore b/lib/git/testdata/IsIgnored/.gitignore
new file mode 100644
index 00000000..15989de8
--- /dev/null
+++ b/lib/git/testdata/IsIgnored/.gitignore
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# SPDX-FileCopyrightText: 2025 M. Shulhan <ms@kilabit.info>
+
+# comment
+  # comment
+  vendor/  # ignore vendor directory, but not vendor file.
+/hello.*    # ignore hello at root, but not foo/hello.go.
+!hello.go
diff --git a/lib/git/testdata/IsIgnored/foo/hello.go b/lib/git/testdata/IsIgnored/foo/hello.go
new file mode 100644
index 00000000..b61e7105
--- /dev/null
+++ b/lib/git/testdata/IsIgnored/foo/hello.go
@@ -0,0 +1,4 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// SPDX-FileCopyrightText: 2025 M. Shulhan <ms@kilabit.info>
+
+package foo
diff --git a/lib/git/testdata/IsIgnored/vendor/empty b/lib/git/testdata/IsIgnored/vendor/empty
new file mode 100644
index 00000000..62f13a9e
--- /dev/null
+++ b/lib/git/testdata/IsIgnored/vendor/empty
@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// SPDX-FileCopyrightText: 2025 M. Shulhan <ms@kilabit.info>
diff --git a/lib/git/testdata/New/fail_no_git/.gitignore b/lib/git/testdata/New/fail_no_git/.gitignore
new file mode 100644
index 00000000..62f13a9e
--- /dev/null
+++ b/lib/git/testdata/New/fail_no_git/.gitignore
@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// SPDX-FileCopyrightText: 2025 M. Shulhan <ms@kilabit.info>