From c46939b5308c31cb792ecb8f7f9b3f76191deb71 Mon Sep 17 00:00:00 2001
From: Rich FitzJohn <r.fitzjohn@imperial.ac.uk>
Date: Fri, 11 Aug 2023 10:11:34 +0100
Subject: [PATCH] Extract basic git metadata

---
 pyproject.toml       |  3 ++-
 src/outpack/tools.py | 12 ++++++++++
 tests/test_tools.py  | 57 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 src/outpack/tools.py
 create mode 100644 tests/test_tools.py

diff --git a/pyproject.toml b/pyproject.toml
index dbbaea7..b053eb0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,7 +25,8 @@ classifiers = [
   "Programming Language :: Python :: Implementation :: PyPy",
 ]
 dependencies = [
-  "dataclasses-json"
+  "dataclasses-json",
+  "pygit2"
 ]
 
 [project.urls]
diff --git a/src/outpack/tools.py b/src/outpack/tools.py
new file mode 100644
index 0000000..1216fcf
--- /dev/null
+++ b/src/outpack/tools.py
@@ -0,0 +1,12 @@
+import pygit2
+
+
+def git_info(path):
+    repo = pygit2.discover_repository(path)
+    if not repo:
+        return None
+    repo = pygit2.Repository(repo)
+    sha = str(repo.head.target)
+    branch = repo.head.shorthand
+    url = [x.url for x in repo.remotes]
+    return {"sha": sha, "branch": branch, "url": url}
diff --git a/tests/test_tools.py b/tests/test_tools.py
new file mode 100644
index 0000000..3ffdfea
--- /dev/null
+++ b/tests/test_tools.py
@@ -0,0 +1,57 @@
+import pygit2
+
+from outpack.tools import git_info
+
+
+def simple_git_example(path, remote=None):
+    d = path / "subdir"
+    d.mkdir()
+    f = d / "file"
+    f.write_text("hello")
+    repo = pygit2.init_repository(path)
+    repo.index.add_all()
+    author = pygit2.Signature("Alice Author", "alice@example.com")
+    message = "Initial commit"
+    tree = repo.index.write_tree()
+    result = repo.create_commit("HEAD", author, author, message, tree, [])
+    if remote:
+        for name, url in remote:
+            repo.remotes.create(name, url)
+    return str(result)
+
+
+def test_git_report_no_info_without_git_repo(tmp_path):
+    p = tmp_path / "sub"
+    p.mkdir()
+    assert git_info(p) is None
+
+
+def test_git_report_git_info_if_possible(tmp_path):
+    sha = simple_git_example(tmp_path)
+    res = git_info(tmp_path)
+    # This default branch name won't be robust to changes in future
+    # git versions
+    assert res == {"branch": "master", "sha": sha, "url": []}
+
+
+def test_git_report_single_url(tmp_path):
+    simple_git_example(tmp_path, [("origin", "https://example.com/git")])
+    res = git_info(tmp_path)
+    assert res["url"] == ["https://example.com/git"]
+
+
+def test_git_report_several_urls(tmp_path):
+    simple_git_example(
+        tmp_path,
+        [
+            ("origin", "https://example.com/git"),
+            ("other", "https://example.com/git2"),
+        ],
+    )
+    res = git_info(tmp_path)
+    assert res["url"] == ["https://example.com/git", "https://example.com/git2"]
+
+
+def test_git_report_from_subdir(tmp_path):
+    simple_git_example(tmp_path)
+    assert git_info(tmp_path) == git_info(tmp_path / "subdir")