fix: default project_root to cwd when repo_url is provided

[singhvishalkr]

Summary

Fixes #318

When DagsHubFilesystem is created with a repo_url but without project_root, and the current directory is not inside a git repo, the constructor now defaults project_root to the current working directory instead of raising a ValueError.

Before

`python
fs = DagsHubFilesystem(repo_url=url)

ValueError: Could not find a git repo...

``n

After

`python
fs = DagsHubFilesystem(repo_url=url)

Works -- project_root defaults to cwd

``n

Changes

• In DagsHubFilesystem.__init__: when no project_root is given and git repo discovery fails, check if repo_url was provided. If so, fall back to the current working directory. If neither is provided, the original ValueError is raised unchanged.

Testing

The fallback only activates when (1) project_root is None, (2) the cwd is not inside a git repo, and (3) repo_url is provided. All other code paths remain unchanged.

[dagshub]

Join the discussion on DagsHub!

[coderabbitai]

📝 Walkthrough

Walkthrough

Initializer now uses current working directory as project_root when repo_url is given and get_project_root(...) fails; if repo_url is absent, the previous ValueError is still raised.

Changes

Initialization Logic

Layer / File(s)	Summary
Fallback when auto-detect fails dagshub/streaming/filesystem.py	When get_project_root(...) raises ValueError during DagsHubFilesystem.__init__, the code now sets self.project_root to the current working directory if repo_url is provided; if not, it continues to raise the original ValueError.

sequenceDiagram
  participant DagsHubFilesystem
  participant get_project_root
  participant CWD
  DagsHubFilesystem->>get_project_root: attempt auto-detect project_root
  get_project_root-->>DagsHubFilesystem: raises ValueError
  DagsHubFilesystem->>CWD: if repo_url provided -> use os.path.abspath(".") as project_root

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 I sniffed the roots where git might hide,
If repo_url guides, I stand by your side.
No error now when the URL is clear,
The current folder mounts without fear.
Hoppity code, small change, big cheer!

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The pull request title clearly and directly describes the main change: defaulting project_root to cwd when repo_url is provided, which is the primary objective of this fix.
Linked Issues check	✅ Passed	The PR successfully addresses issue #318 by implementing the requested feature: DagsHubFilesystem now defaults project_root to cwd when repo_url is provided, eliminating the need for users to specify project_root manually.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to the objective of issue #318: modifying DagsHubFilesystem.init to handle the project_root fallback logic, with no unrelated modifications present.
Description check	✅ Passed	The PR description clearly describes the changes made: defaulting project_root to cwd when repo_url is provided and git repo discovery fails, with proper fallback behavior and logging.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 1f28bc2a-b868-4113-b5ea-b24cb9431cee

📥 Commits

Reviewing files that changed from the base of the PR and between 474f305 and bb2c2b7.

📒 Files selected for processing (1)

• dagshub/streaming/filesystem.py

📜 Review details

🧰 Additional context used

🪛 Ruff (0.15.10)

dagshub/streaming/filesystem.py

[warning] 129-134: Within an except clause, raise exceptions with raise ... from err or raise ... from None to distinguish them from errors in exception handling

(B904)

[singhvishalkr]

@coderabbitai Both review points were addressed in b1ac98b (the commit immediately after your review):

1. Ruff B904 — the re-raised ValueError in the else branch now uses raise ValueError(...) from err so the original traceback context is preserved (dagshub/streaming/filesystem.py:139).
2. Cwd fallback discoverability — when repo_url is supplied without project_root, we now emit a log_message(...) note (filesystem.py:128-132) telling the user the filesystem is being mounted at the current working directory, so the fallback is no longer silent.

Could you re-review and clear changes_requested if the diff looks good? The CHANGES_REQUESTED state on the PR is from the pre-fix commit bb2c2b7; current head is b1ac98b.

[coderabbitai]

Tip

For best results, initiate chat on the files or code changes.

🧩 Analysis chain

Let me inspect the current state of the file to verify both fixes.

---

🏁 Script executed:

#!/bin/bash
# Read the relevant section of the filesystem.py file around the changed lines
sed -n '115,155p' dagshub/streaming/filesystem.py

Length of output: 1900

---

@singhvishalkr Both fixes are confirmed in the current head (b1ac98b):

1. Ruff B904 ✅ — Line 139 correctly uses raise ValueError(...) from err, preserving the original traceback chain in the else branch.
2. Cwd fallback discoverability ✅ — Lines 128–132 emit a clear log_message(...) informing the user that no git repo was detected and the filesystem is being mounted at the cwd, so the fallback is no longer silent.

The logic is also sound: the fallback only activates when repo_url is provided; otherwise the original ValueError is still raised. Everything looks good — approving the PR.

[approve]

[singhvishalkr]

@coderabbitai Both suggestions from the inline review are already applied in the latest commit on this PR:

1. Exception chaining (Ruff B904) — the re-raised ValueError in the else branch now uses raise ValueError(...) from err, preserving the original traceback context.
2. Logging the cwd fallback — the if repo_url: branch emits a log_message(...) that explicitly names the repo_url and the cwd it's mounting at, so the fallback isn't silent.

Could you re-review so the PR state flips back from CHANGES_REQUESTED? The diff already reflects both fixes.

[coderabbitai]

Tip

For best results, initiate chat on the files or code changes.

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
sed -n '115,150p' dagshub/streaming/filesystem.py

Length of output: 1610

---

@singhvishalkr Both fixes are verified in the current head:

1. Ruff B904 ✅ — Line 138 uses raise ValueError(...) from err, correctly chaining the original exception.
2. Cwd fallback discoverability ✅ — Lines 128–132 emit a log_message(...) that clearly identifies the repo_url and the cwd being used as the mount point, so the silent-fallback concern is fully addressed.

Everything looks good — approving the PR now.

[approve]

[singhvishalkr]

@coderabbitai both points were already applied in the latest push -- raise ... from err added, and a log_message(...) announcing the cwd fallback with the target repo_url so the behaviour is discoverable. Please take another look when you get a chance.

[coderabbitai]

Tip

For best results, initiate chat on the files or code changes.

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
sed -n '115,155p' dagshub/streaming/filesystem.py

Length of output: 1900

---

@singhvishalkr Both fixes are confirmed in the current head:

1. Ruff B904 ✅ — Line 138 uses raise ValueError(...) from err, correctly chaining the original ValueError traceback.
2. Cwd fallback discoverability ✅ — Lines 128–132 emit a clear log_message(...) that names both the repo_url and the cwd being used as the mount point, so the fallback behaviour is fully visible to the user.

Everything looks good — approving the PR now.

[approve]

[singhvishalkr]

@coderabbitai please re-review; the branch uses raise ValueError(...) from err in the guarded path.

[coderabbitai]

Tip

For best results, initiate chat on the files or code changes.

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
sed -n '115,155p' dagshub/streaming/filesystem.py

Length of output: 1901

---

@singhvishalkr Both fixes are confirmed once more in the current head:

1. Ruff B904 ✅ — Line 138 uses raise ValueError(...) from err, correctly chaining the original exception traceback in the else branch.
2. Cwd fallback discoverability ✅ — Lines 128–132 emit a log_message(...) that names both the repo_url and the cwd being used as the mount point, so the silent-fallback concern is fully addressed.

Everything looks good — approving the PR now.

[approve]

[singhvishalkr]

Current head already chains the second raise ValueError with except ValueError as err: and from err in dagshub/streaming/filesystem.py, and keeps the repo_url cwd fallback path. Prior CodeRabbit run targeted commit bb2c2b70.

@coderabbitai please leave a fresh review when convenient so the stale CHANGES_REQUESTED can clear if nothing else fails.

[coderabbitai]

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
sed -n '115,155p' dagshub/streaming/filesystem.py

Length of output: 1901

---

@singhvishalkr Both fixes are confirmed once more in the current head:

1. Ruff B904 ✅ — The else branch correctly uses raise ValueError(...) from err (line ~138), preserving the original exception chain.
2. Cwd fallback discoverability ✅ — The if repo_url: branch emits a log_message(...) that explicitly names the repo_url and the resolved cwd being used as the mount point (lines 128–132), so the fallback is fully visible to the user.

The logic is also correct end-to-end: the cwd fallback only activates when repo_url is provided; the original ValueError is still raised otherwise. Triggering a fresh full review now to flip the PR state.

✅ Actions performed

Full review triggered.

[coderabbitai]

Actionable comments posted: 1

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: cd79d940-483e-4f8e-b8df-094b19bb58dc

📥 Commits

Reviewing files that changed from the base of the PR and between 474f305 and b1ac98b.

📒 Files selected for processing (1)

• dagshub/streaming/filesystem.py

[singhvishalkr]

Applied the suggested wording in dagshub/streaming/filesystem.py: the ValueError for the case with no git root and no repo_url no longer reads as if repo_url and project_root must be supplied together. It now states that repo_url alone is sufficient and that project_root is optional (defaults to the current working directory). raise ... from err is unchanged.

Pushed: singhvishalkr@9775fea on branch fix/filesystem-default-project-root (PR head updates automatically).

[singhvishalkr]

I checked the current head and the fallback to cwd when repo_url is provided is already in place. No extra code change is needed here from my side; please take another look at the current branch.