Replace GitPython with pygit2

Replace the use of GitPython package with pygit2.  The latter seems
to have better git support, in particular it supports the newer index
versions 3 and 4.  Since it is backed by the libgit2 library that is
also used by Cargo, it seems to have the best chances of being updated
for compatibility with new git versions.

Admittedly, the API feels very low-level.  In particular, it is
necessary to explicitly request writing changes to index back,
and explicitly reread it when it's modified externally (e.g. via another
`pygit2.Repository` instance, as in tests).  On the plus side, it does
not invoke `git` at all -- everything is done by the library.

Fixes conda-forge#2116

conda_smithy/feedstock_io.py

@@ -7,22 +7,23 @@
 def get_repo(path, search_parent_directories=True):
     repo = None
     try:
-        import git
-
-        repo = git.Repo(
-            path, search_parent_directories=search_parent_directories
-        )
+        import pygit2
+
+        if search_parent_directories:
+            path = pygit2.discover_repository(path)
+        if path is not None:
+            repo = pygit2.Repository(
+                path, pygit2.enums.RepositoryOpenFlag.NO_SEARCH
+            )
     except ImportError:
         pass
-    except git.InvalidGitRepositoryError:
-        pass
 
     return repo
 
 
 def get_repo_root(path):
     try:
-        return get_repo(path).working_tree_dir
+        return get_repo(path).workdir.rstrip(os.path.sep)
     except AttributeError:
         return None
 
@@ -32,8 +33,13 @@ def set_exe_file(filename, set_exe=True):
 
     repo = get_repo(filename)
     if repo:
-        mode = "+x" if set_exe else "-x"
-        repo.git.execute(["git", "update-index", f"--chmod={mode}", filename])
+        index_entry = repo.index[os.path.relpath(filename, repo.workdir)]
+        if set_exe:
+            index_entry.mode |= all_execute_permissions
+        else:
+            index_entry.mode &= ~all_execute_permissions
+        repo.index.add(index_entry)
+        repo.index.write()
 
     mode = os.stat(filename).st_mode
     if set_exe:
@@ -54,7 +60,8 @@ def write_file(filename):
 
     repo = get_repo(filename)
     if repo:
-        repo.index.add([filename])
+        repo.index.add(os.path.relpath(filename, repo.workdir))
+        repo.index.write()
 
 
 def touch_file(filename):
@@ -68,7 +75,8 @@ def remove_file_or_dir(filename):
 
     repo = get_repo(filename)
     if repo:
-        repo.index.remove([filename], r=True)
+        repo.index.remove_all([f"filename/**"])
+        repo.index.write()
     shutil.rmtree(filename)
 
 
@@ -77,7 +85,11 @@ def remove_file(filename):
 
     repo = get_repo(filename)
     if repo:
-        repo.index.remove([filename])
+        try:
+            repo.index.remove(os.path.relpath(filename, repo.workdir))
+            repo.index.write()
+        except IOError:  # this is specifically "file not in index"
+            pass
 
     os.remove(filename)
 
@@ -106,4 +118,5 @@ def copy_file(src, dst):
 
     repo = get_repo(dst)
     if repo:
-        repo.index.add([dst])
+        repo.index.add(os.path.relpath(dst, repo.workdir))
+        repo.index.write()

environment.yml

@@ -22,6 +22,7 @@ dependencies:
   - requests
   - pycryptodome
   - gitpython
+  - pygit2
   - pygithub >=2,<3
   - ruamel.yaml
   - conda-forge-pinning

tests/test_feedstock_io.py

@@ -8,8 +8,7 @@
 import tempfile
 import unittest
 
-import git
-from git.index.typ import BlobFilter
+import pygit2
 
 import conda_smithy.feedstock_io as fio
 
@@ -27,7 +26,7 @@ def parameterize():
     ]:
         for get_repo in [
             lambda tmp_dir: None,
-            lambda tmp_dir: git.Repo.init(tmp_dir),
+            lambda tmp_dir: pygit2.init_repository(tmp_dir),
         ]:
             try:
                 tmp_dir = tempfile.mkdtemp()
@@ -64,7 +63,7 @@ def test_repo(self):
                 self.assertTrue(fio.get_repo(pathfunc(tmp_dir)) is None)
             else:
                 self.assertIsInstance(
-                    fio.get_repo(pathfunc(tmp_dir)), git.Repo
+                    fio.get_repo(pathfunc(tmp_dir)), pygit2.Repository
                 )
                 possible_repo_subdir = os.path.join(
                     tmp_dir,
@@ -85,34 +84,34 @@ def test_set_exe_file(self):
 
         for set_exe in [True, False]:
             for tmp_dir, repo, pathfunc in parameterize():
-                filename = "test.txt"
-                filename = os.path.join(tmp_dir, filename)
+                basename = "test.txt"
+                filename = os.path.join(tmp_dir, basename)
                 with open(filename, "w", encoding="utf-8", newline="\n") as fh:
                     fh.write("")
                 if repo is not None:
-                    repo.index.add([filename])
+                    repo.index.add(basename)
+                    repo.index.write()
 
                 fio.set_exe_file(pathfunc(filename), set_exe)
 
                 file_mode = os.stat(filename).st_mode
                 self.assertEqual(file_mode & set_mode, int(set_exe) * set_mode)
                 if repo is not None:
-                    blob = next(repo.index.iter_blobs(BlobFilter(filename)))[1]
+                    repo.index.read()
+                    blob = repo.index[basename]
                     self.assertEqual(
                         blob.mode & set_mode, int(set_exe) * set_mode
                     )
 
     def test_write_file(self):
         for tmp_dir, repo, pathfunc in parameterize():
-            for filename in ["test.txt", "dir1/dir2/test.txt"]:
-                filename = os.path.join(tmp_dir, filename)
+            for basename in ["test.txt", "dir1/dir2/test.txt"]:
+                filename = os.path.join(tmp_dir, basename)
 
                 write_text = "text"
 
                 with fio.write_file(pathfunc(filename)) as fh:
                     fh.write(write_text)
-                if repo is not None:
-                    repo.index.add([filename])
 
                 read_text = ""
                 with open(filename, encoding="utf-8") as fh:
@@ -121,15 +120,16 @@ def test_write_file(self):
                 self.assertEqual(write_text, read_text)
 
                 if repo is not None:
-                    blob = next(repo.index.iter_blobs(BlobFilter(filename)))[1]
-                    read_text = blob.data_stream[3].read().decode("utf-8")
+                    repo.index.read()
+                    blob = repo.index[basename]
+                    read_text = repo[blob.id].data.decode("utf-8")
 
                     self.assertEqual(write_text, read_text)
 
     def test_touch_file(self):
         for tmp_dir, repo, pathfunc in parameterize():
-            for filename in ["test.txt", "dir1/dir2/test.txt"]:
-                filename = os.path.join(tmp_dir, filename)
+            for basename in ["test.txt", "dir1/dir2/test.txt"]:
+                filename = os.path.join(tmp_dir, basename)
 
                 fio.touch_file(pathfunc(filename))
 
@@ -140,33 +140,33 @@ def test_touch_file(self):
                 self.assertEqual("", read_text)
 
                 if repo is not None:
-                    blob = next(repo.index.iter_blobs(BlobFilter(filename)))[1]
-                    read_text = blob.data_stream[3].read().decode("utf-8")
+                    repo.index.read()
+                    blob = repo.index[basename]
+                    read_bytes = repo[blob.id].data
 
-                    self.assertEqual("", read_text)
+                    self.assertEqual(b"", read_bytes)
 
     def test_remove_file(self):
         for tmp_dir, repo, pathfunc in parameterize():
-            for filename in ["test.txt", "dir1/dir2/test.txt"]:
-                dirname = os.path.dirname(filename)
+            for basename in ["test.txt", "dir1/dir2/test.txt"]:
+                dirname = os.path.dirname(basename)
                 if dirname and not os.path.exists(dirname):
                     os.makedirs(dirname)
 
-                filename = os.path.join(tmp_dir, filename)
+                filename = os.path.join(tmp_dir, basename)
 
                 with open(filename, "w", encoding="utf-8", newline="\n") as fh:
                     fh.write("")
                 if repo is not None:
-                    repo.index.add([filename])
+                    repo.index.add(basename)
+                    repo.index.write()
 
                 self.assertTrue(os.path.exists(filename))
                 if dirname:
                     self.assertTrue(os.path.exists(dirname))
                     self.assertTrue(os.path.exists(os.path.dirname(dirname)))
                 if repo is not None:
-                    self.assertTrue(
-                        list(repo.index.iter_blobs(BlobFilter(filename)))
-                    )
+                    self.assertIsNotNone(repo.index[basename])
 
                 fio.remove_file(pathfunc(filename))
 
@@ -175,17 +175,16 @@ def test_remove_file(self):
                     self.assertFalse(os.path.exists(dirname))
                     self.assertFalse(os.path.exists(os.path.dirname(dirname)))
                 if repo is not None:
-                    self.assertFalse(
-                        list(repo.index.iter_blobs(BlobFilter(filename)))
-                    )
+                    repo.index.read()
+                    self.assertRaises(KeyError, lambda: repo.index[basename])
 
     def test_copy_file(self):
         for tmp_dir, repo, pathfunc in parameterize():
-            filename1 = "test1.txt"
-            filename2 = "test2.txt"
+            basename1 = "test1.txt"
+            basename2 = "test2.txt"
 
-            filename1 = os.path.join(tmp_dir, filename1)
-            filename2 = os.path.join(tmp_dir, filename2)
+            filename1 = os.path.join(tmp_dir, basename1)
+            filename2 = os.path.join(tmp_dir, basename2)
 
             write_text = "text"
             with open(filename1, "w", encoding="utf-8", newline="\n") as fh:
@@ -194,18 +193,15 @@ def test_copy_file(self):
             self.assertTrue(os.path.exists(filename1))
             self.assertFalse(os.path.exists(filename2))
             if repo is not None:
-                self.assertFalse(
-                    list(repo.index.iter_blobs(BlobFilter(filename2)))
-                )
+                self.assertRaises(KeyError, lambda: repo.index[basename2])
 
             fio.copy_file(pathfunc(filename1), pathfunc(filename2))
 
             self.assertTrue(os.path.exists(filename1))
             self.assertTrue(os.path.exists(filename2))
             if repo is not None:
-                self.assertTrue(
-                    list(repo.index.iter_blobs(BlobFilter(filename2)))
-                )
+                repo.index.read()
+                self.assertIsNotNone(repo.index[basename2])
 
             read_text = ""
             with open(filename2, encoding="utf-8") as fh:
@@ -214,8 +210,8 @@ def test_copy_file(self):
             self.assertEqual(write_text, read_text)
 
             if repo is not None:
-                blob = next(repo.index.iter_blobs(BlobFilter(filename2)))[1]
-                read_text = blob.data_stream[3].read().decode("utf-8")
+                blob = repo.index[basename2]
+                read_text = repo[blob.id].data.decode("utf-8")
 
                 self.assertEqual(write_text, read_text)