fix(chroma): version incompatibility fails silently + NoneType 'delete' crash

[Pankajsharma99max]

Fixes #1405

list_collections()'s return shape differs across chromadb client versions: newer clients (>=0.6) return a list of collection name strings, older clients (<0.6) return a list of Collection objects exposing .name. _doesCollectionExist compared self.collection (a str) directly against the raw list, which only worked for the string-returning shape -- against an older server (e.g. Chroma 0.5.18) it silently evaluated to "collection does not exist" even when it did, and a raw client/server incompatibility during list_collections() (e.g. KeyError('_type')) propagated as an opaque error with no indication of the real cause.

Downstream, flush() called self.collectionObj.delete(...) / .upsert(...) without checking whether collectionObj had actually been resolved, so a prior silent failure surfaced later as an opaque AttributeError: 'NoneType' object has no attribute 'delete' instead of an actionable message -- appearing to the user as "0 done, 1 error" during ingestion with no clue why, and downstream chat systems then answering from training data instead of indexed content.

Fix

• Normalize list_collections() results to a set of names regardless of whether the client returns strings or Collection-like objects.
• Wrap list_collections() failures with a message naming the host/port and pointing at a likely version mismatch, instead of letting a raw KeyError propagate.
• Fail fast in flush() with a clear, actionable error when the collection was never resolved, instead of letting it crash deep inside a per-chunk write.

A hard client/server version gate was intentionally left out of scope -- that's a call for maintainers who know the actual supported compatibility matrix. This PR fixes the underlying behavioral defect and makes failures surface clearly, which resolves the reported crash and silent-failure symptoms directly.

Testing

• Added nodes/test/chroma/test_collection_version_compat.py (7 new tests) covering both the version-shape bug and the flush() guard.
• Verified (locally, by reverting the fix) that these tests fail against the pre-fix code with exactly the symptoms described in the issue (assert False is True on the version-shape test; raw '_type' and 'NoneType' object has no attribute 'delete' messages on the other two), and pass after the fix.
• ruff check / ruff format --diff clean on all changed files.

Summary by CodeRabbit

• Bug Fixes
  • Improved collection detection across Chroma version differences, so existing collections are recognized more reliably.
  • Added clearer error messages when collection lookup fails or when chunk ingestion can’t proceed because the collection isn’t initialized.
  • Prevented a downstream opaque NoneType/attribute error by failing fast with actionable feedback.
• Tests
  • Added regression coverage for collection existence checks across multiple Chroma response shapes.
  • Added a test for the new fail-fast behavior during chunk ingestion.

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ℹ️ Recent review info

⚙️ Run configuration

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Run ID: 79709a1f-618a-4d6d-ace2-6ce4d8217cb4

📥 Commits

Reviewing files that changed from the base of the PR and between 80c6654 and 03f286f.

📒 Files selected for processing (2)

• nodes/src/nodes/chroma/chroma.py
• nodes/test/chroma/test_collection_version_compat.py

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📝 Walkthrough

Walkthrough

Modified Store._doesCollectionExist in chroma.py to wrap list_collections() calls with error handling and normalize returned collection identifiers across Chroma client versions. Added a guard in addChunks's flush to raise a clear error when collectionObj is unresolved. Added regression tests with stub modules.

Changes

Chroma version compatibility

Layer / File(s)	Summary
Collection existence check and flush guard nodes/src/nodes/chroma/chroma.py	_doesCollectionExist wraps list_collections() in try/except with a descriptive error and normalizes returned identifiers (strings or objects with .name); flush raises an actionable error when collectionObj is None instead of failing with an opaque NoneType error.
Regression tests and stub harness nodes/test/chroma/test_collection_version_compat.py	New test module with fake chromadb stubs (_FakeCollectionRef, _FakeCollectionObj, _FakeHttpClient), module-loading helpers (_install_min_stubs, _scoped_stubs, _load_store_class, _bare_store), and test classes validating _doesCollectionExist across return shapes/errors and flush's guard against unresolved collectionObj.

Estimated code review effort: 2 (Simple) | ~15 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Caller
  participant Store
  participant ChromaClient

  Caller->>Store: addChunks(chunks, checkCollection)
  Store->>Store: _doesCollectionExist()
  Store->>ChromaClient: list_collections()
  alt list_collections fails
    ChromaClient-->>Store: raises error
    Store-->>Caller: raise descriptive version-mismatch error
  else success
    ChromaClient-->>Store: names or objects
    Store->>Store: normalize to set of names
    Store-->>Caller: True/False
  end
  Store->>Store: flush()
  alt collectionObj is None
    Store-->>Caller: raise "not initialized" error
  else
    Store->>ChromaClient: delete/upsert
  end

Loading

Related issues: #1405 — Chroma version incompatibility fails silently and causes a NoneType delete crash; this PR adds version-normalization handling in _doesCollectionExist and a fail-fast guard in flush.

Suggested labels: bug, chroma, tests

Suggested reviewers: rocketride-org/backend-maintainers

_{🐰 A rabbit checked the collections twice,
Strings or objects—handled nice,
No more crashes, silent and sly,
Now errors speak before chunks die.
Tests stand guard with stubs so light. 🥕}

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the Chroma version-compatibility fix and the NoneType cleanup crash.
Linked Issues check	✅ Passed	The changes address the Chroma return-shape mismatch, wrap list_collections failures, and guard flush when collectionObj is unset.
Out of Scope Changes check	✅ Passed	The PR stays focused on Chroma compatibility fixes and regression tests without unrelated changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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