Add hash-object support to Git class and update CLI parser logic

- Implemented `hash_object` method in the `Git` class with optional write functionality.
- Updated CLI parser to include `hash-object` command with `-w` flag support.
- Enhanced `create_blob` to conditionally write object files.
- Added unit tests for `hash_object` and updated parser tests accordingly.
- Refactored `change_to_tmp_dir` fixture to return the temporary directory path.

Author: LesPrimus

app/main.py

@@ -11,6 +11,8 @@ def main():
             return git.init_repo()
         case "cat-file":
             return git.cat_file(args.hash, pretty_print=args.pretty_print)
+        case "hash-object":
+            return git.hash_object(args.path, write=args.write)
         case _:
             raise RuntimeError(f"Unknown command #{args.command}")
 

app/models/git.py

@@ -4,6 +4,8 @@
 
 __all__ = ["Git"]
 
+from app.utils import create_blob
+
 NULL_BYTE = b"\x00"
 
 
@@ -30,3 +32,9 @@ def cat_file(cls, hash_: str, *, pretty_print: bool = False):
         if pretty_print:
             sys.stdout.write(body.decode())
         return Blob(header=header, body=body)
+
+    @classmethod
+    def hash_object(cls, path: pathlib.Path, *, write: bool = False):
+        with path.open("r") as f:
+            hash_value = create_blob(f.read(), write=write)
+        return hash_value

app/utils.py

@@ -18,10 +18,15 @@ def get_parser():
     cat_file_parser.add_argument(
         "hash",
     )
+
+    # hash_object
+    hash_object_parser = subparsers.add_parser("hash-object")
+    hash_object_parser.add_argument("path", type=pathlib.Path)
+    hash_object_parser.add_argument("-w", "--write", action="store_true")
     return parser
 
 
-def create_blob(content: str) -> str:
+def create_blob(content: str, *, write: bool = True) -> str:
     # Format the blob object
     blob = f"blob {len(content)}\0{content}"
     # Convert to bytes
@@ -35,13 +40,11 @@ def create_blob(content: str) -> str:
     hash_object = hashlib.sha1(blob_bytes)
     hash_value = hash_object.hexdigest()
 
-    # Create directory structure
-    path = pathlib.Path(".git/objects", hash_value[:2])
-    path.mkdir(exist_ok=True)
+    if write:
+        # Create directory structure
+        path = pathlib.Path(".git/objects", hash_value[:2])
+        path.mkdir(exist_ok=True)
 
-    with (path / hash_value[2:]).open("wb") as f:
-        f.write(compressed)
-    # Write the compressed blob
-    # with open(path / hash_value[2:], 'wb') as f:
-    #     f.write(compressed)
+        with (path / hash_value[2:]).open("wb") as f:
+            f.write(compressed)
     return hash_value

tests/test_git.py

@@ -6,10 +6,11 @@
 from app.main import Git
 from app.utils import create_blob
 
+
 @pytest.fixture
 def change_to_tmp_dir(tmp_path):
     with contextlib.chdir(tmp_path):
-        yield
+        yield tmp_path
 
 
 class TestGit:
@@ -29,6 +30,20 @@ def test_cat_file(self, change_to_tmp_dir):
         assert blob.header == f"blob {len(blob.body)}".encode()
         assert blob.body == b"some content"
 
-    def test_hash_object(self, change_to_tmp_dir):
+    @pytest.mark.parametrize("write", [True, False])
+    @pytest.mark.parametrize(
+        "content, expected_hash_value",
+        [("hello world\n", "3b18e512dba79e4c8300dd08aeb37f8e728b8dad")],
+    )
+    def test_hash_object(self, change_to_tmp_dir, content, expected_hash_value, write):
         git = Git()
         git.init_repo()
+        tmp_file = change_to_tmp_dir / "file.txt"
+        tmp_file.write_text(content)
+        hash_value = git.hash_object(tmp_file, write=write)
+        assert hash_value == expected_hash_value
+        assert len(hash_value) == 40
+        expected_path = (
+            change_to_tmp_dir / ".git/objects" / hash_value[:2] / hash_value[2:]
+        )
+        assert expected_path.exists() == write

tests/test_utils.py

@@ -1,3 +1,4 @@
+import pathlib
 from argparse import Namespace
 
 import pytest
@@ -17,6 +18,18 @@
             ["cat-file", "-p", "some_hash"],
             Namespace(command="cat-file", hash="some_hash", pretty_print=True),
         ),
+        (
+            ["hash-object", "some_file.txt"],
+            Namespace(
+                command="hash-object", path=pathlib.Path("some_file.txt"), write=False
+            ),
+        ),
+        (
+            ["hash-object", "-w", "some_file.txt"],
+            Namespace(
+                command="hash-object", path=pathlib.Path("some_file.txt"), write=True
+            ),
+        ),
     ],
 )
 def test_parser(params, expected):