# \[Python\]\[#FE4\] write tree - object content differs **URL:** \ **Category:** Challenges\ **Tags:** challenge:git\ **Created:** [March 15, 2025, 9:00pm UTC](https://forum.codecrafters.io/t/python-fe4-write-tree-object-content-differs/6843 "2025-03-15T21:00:20Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![neerajnangireddy](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/neerajnangireddy/32/7122_2.png) [@neerajnangireddy](https://forum.codecrafters.io/u/neerajnangireddy)\ **Post date:** [March 15, 2025, 9:00pm UTC](https://forum.codecrafters.io/t/python-fe4-write-tree-object-content-differs/6843/1 "2025-03-15T21:00:20Z")
I’m stuck on Stage #FE4. I have implemented a recursive write tree but the output differs. Here are my logs: ```auto [user@fedora codecrafters-git-python]$ codecrafters test Initiating test run... ⏳ Turbo test runners busy. You are in queue. Upgrade to skip the wait: https://codecrafters.io/turbo Running tests. Logs should appear shortly... [compile] Moved ./.codecrafters/run.sh → ./your_program.sh [compile] Compilation successful. [tester::#FE4] Running tests for Stage #FE4 (Write a tree object) [tester::#FE4] $ ./your_program.sh init [your_program] Initialized git directory [tester::#FE4] Creating some files & directories [tester::#FE4] $ ./your_program.sh write-tree [your_program] 35f788256ebc421c93c7dc6bf4b7878cde4319c6 [tester::#FE4] Found git object file written at .git/objects/35/f788256ebc421c93c7dc6bf4b7878cde4319c6. [tester::#FE4] Git object file doesn't match official Git implementation. Diff after zlib decompression: [tester::#FE4] [tester::#FE4] Expected (bytes 0-100), hexadecimal: | ASCII: [tester::#FE4] 74 72 65 65 20 39 38 00 34 30 30 30 30 20 64 6f 6f 00 57 77 | tree 98.40000 doo.Ww [tester::#FE4] de 63 c8 c1 d7 5b 22 f3 77 3b 04 56 15 ac 05 cf 7f 22 34 30 | .c...[".w;.V....."40 [tester::#FE4] 30 30 30 20 6d 6f 6e 6b 65 79 00 dd 40 10 af 93 91 79 eb b4 | 000 monkey..@....y.. [tester::#FE4] 08 df ca 79 f7 f3 94 55 c7 60 87 31 30 30 36 34 34 20 76 61 | ...y...U.`.100644 va [tester::#FE4] 6e 69 6c 6c 61 00 eb c8 50 fa fe d7 7a 95 a3 4a 95 1a 06 b2 | nilla...P...z..J.... [tester::#FE4] [tester::#FE4] Actual (bytes 0-100), hexadecimal: | ASCII: [tester::#FE4] 74 72 65 65 20 39 38 00 34 30 30 30 30 20 64 6f 6f 00 07 9f | tree 98.40000 doo... [tester::#FE4] 59 2f 6f 98 bf 6e 62 82 18 e6 ca cd 80 6c bb 58 af b4 34 30 | Y/o..nb......l.X..40 [tester::#FE4] 30 30 30 20 6d 6f 6e 6b 65 79 00 3e a3 2e c9 03 3e b9 b9 75 | 000 monkey.>....>..u [tester::#FE4] 75 02 81 24 b9 20 dc ab 0a 46 df 31 30 30 36 34 34 20 76 61 | u..$. ...F.100644 va [tester::#FE4] 6e 69 6c 6c 61 00 eb c8 50 fa fe d7 7a 95 a3 4a 95 1a 06 b2 | nilla...P...z..J.... [tester::#FE4] [tester::#FE4] Git object file doesn't match official Git implementation [tester::#FE4] Test failed (try setting 'debug: true' in your codecrafters.yml to see more details) ``` And here’s a snippet of my code: ```python 57 def hash_object(filepath, write_enabled=False): 58 filepath = Path(filepath) 59 if not filepath.is_file(): 60 print("Object not found.") 61 raise FileNotFoundError 62 with open(filepath, "rb") as f: 63 contents = f.read() 64 size = len(contents) 65 header = f"blob {size}" 66 blob = header.encode() + b"\0" + contents 67 raw_sha = hashlib.sha1(blob) 68 sha_hash = raw_sha.hexdigest() 69 if write_enabled: 70 compressed_blob = zlib.compress(blob) 71 sub_dir = sha_hash[:2] 72 obj_name = sha_hash[2:] 73 if not (Path(".git/objects") / sub_dir).is_dir(): 74 Path.mkdir(Path(".git/objects") / sub_dir) 75 with open(Path(".git/objects") / sub_dir / obj_name, "wb") as f: 76 f.write(compressed_blob) 77 return (raw_sha.digest()[:20], sha_hash) 78 79 80 def write_tree(loc: Path): 81 tree_contents = b"" 82 for file in sorted(list(loc.iterdir())): 83 if file.name == ".git": 84 continue 85 elif file.is_file(): 86 mode = "100644" 87 raw_sha, _ = hash_object(file) 88 else: 89 mode = "40000" 90 raw_sha, _ = write_tree(file) 91 tree_contents += f"{mode} {file.name}".encode() + b"\0" + raw_sha 92 # print(mode, file.name, raw_sha) 93 94 tree_sha = hashlib.sha1(tree_contents) 95 tree_sha_hash = tree_sha.hexdigest() 96 if not (Path(".git/objects") / tree_sha_hash[:2]).is_dir(): 97 Path.mkdir(Path(".git/objects") / tree_sha_hash[:2]) 98 with open(Path(".git/objects") / tree_sha_hash[:2] / tree_sha_hash[2:], "wb") as f: 99 tree_obj = f"tree {len(tree_contents)}".encode() + b"\0" + tree_contents 100 compressed_tree_obj = zlib.compress(tree_obj) 101 f.write(compressed_tree_obj) 102 return tree_sha.digest()[:20], tree_sha_hash ``` ---
**Author:** ![andy1li](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/andy1li/32/10_2.png) [@andy1li](https://forum.codecrafters.io/u/andy1li)\ **Post date:** [March 16, 2025, 5:09am UTC](https://forum.codecrafters.io/t/python-fe4-write-tree-object-content-differs/6843/3 "2025-03-16T05:09:45Z")
Hey @neerajnangireddy, could you [upload your code to GitHub](https://docs.codecrafters.io/features/publish-to-github) and share the link? It will be much easier to debug if I can run it directly. ---
**Author:** ![neerajnangireddy](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/neerajnangireddy/32/7122_2.png) [@neerajnangireddy](https://forum.codecrafters.io/u/neerajnangireddy)\ **Post date:** [March 16, 2025, 7:19am UTC](https://forum.codecrafters.io/t/python-fe4-write-tree-object-content-differs/6843/4 "2025-03-16T07:19:15Z")
> **[GitHub - neerajnangireddy/codecrafters-git-python](https://github.com/neerajnangireddy/codecrafters-git-python/)** > > Contribute to neerajnangireddy/codecrafters-git-python development by creating an account on GitHub. ---
**Author:** ![andy1li](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/andy1li/32/10_2.png) [@andy1li](https://forum.codecrafters.io/u/andy1li)\ **Post date:** [March 17, 2025, 7:37am UTC](https://forum.codecrafters.io/t/python-fe4-write-tree-object-content-differs/6843/6 "2025-03-17T07:37:11Z")
Hey @neerajnangireddy, I tried running your code against the previous stages, but it’s actually no longer passing a previous stage **#IC4 (Read a blob object)**. ![image](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/2X/5/593a41d02111aea626aedebfecaa7774356bd935.png) Suggestions: 1. Use [our CLI](https://docs.codecrafters.io/cli/installation) to test against previous stages by running: ```auto codecrafters test --previous ``` 1. Focus on fixing the early stages first, as later stages depend on them. ---
**Author:** ![neerajnangireddy](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/neerajnangireddy/32/7122_2.png) [@neerajnangireddy](https://forum.codecrafters.io/u/neerajnangireddy)\ **Post date:** [March 17, 2025, 2:14pm UTC](https://forum.codecrafters.io/t/python-fe4-write-tree-object-content-differs/6843/8 "2025-03-17T14:14:00Z")
Hii, I refactored some of my previous stages code and forgot to change the arguments. so previous stages failed. however the login is same. and it still fails the #FE4 stage. The latest changes are pushed to my github. Any help in identifying the error will be helpful. Thank you for the help, ---
**Author:** ![neerajnangireddy](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/neerajnangireddy/32/7122_2.png) [@neerajnangireddy](https://forum.codecrafters.io/u/neerajnangireddy)\ **Post date:** [March 17, 2025, 2:58pm UTC](https://forum.codecrafters.io/t/python-fe4-write-tree-object-content-differs/6843/10 "2025-03-17T14:58:53Z")
I fixed it finally. The thing is I caliculated the hash of the tree without including the header of the tree i.e `tree {size}\0` The modified python code is ```python def write_tree(loc: Path): @@ -91,15 +91,16 @@ def write_tree(loc: Path): tree_contents += f"{mode} {file.name}".encode() + b"\0" + raw_sha # print(mode, file.name, raw_sha) - tree_sha = hashlib.sha1(tree_contents) + tree_obj = f"tree {len(tree_contents)}".encode() + b"\0" + tree_contents + tree_sha = hashlib.sha1(tree_obj) tree_sha_hash = tree_sha.hexdigest() if not (Path(".git/objects") / tree_sha_hash[:2]).is_dir(): Path.mkdir(Path(".git/objects") / tree_sha_hash[:2]) with open(Path(".git/objects") / tree_sha_hash[:2] / tree_sha_hash[2:], "wb") as f: - tree_obj = f"tree {len(tree_contents)}".encode() + b"\0" + tree_contents + # tree_obj = f"tree {len(tree_contents)}".encode() + b"\0" + tree_contents compressed_tree_obj = zlib.compress(tree_obj) f.write(compressed_tree_obj) - return tree_sha.digest()[:20], tree_sha_hash + return tree_sha.digest(), tree_sha_hash ``` Once again thanks of the help ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/3X/7/0/700657133935c15703e22c7c8870394f6e6dc27d.svg) [@system](https://forum.codecrafters.io/u/system)\ **Post date:** [March 22, 2025, 3:09pm UTC](https://forum.codecrafters.io/t/python-fe4-write-tree-object-content-differs/6843/12 "2025-03-22T15:09:23Z")
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