Fix migration 0004 aborting when ix_tags_tag_type is missing

[Constantine1916]

Fixes #15022

Summary

• Migration 0004_drop_tag_type unconditionally calls drop_index("ix_tags_tag_type"). Databases in the wild can be at revision 0003 without that index (tables created by older builds), so the whole upgrade aborts with ValueError: No such index: 'ix_tags_tag_type' and ComfyUI fails to start.
• Inspect the existing indexes on tags and only drop the index when it is present. The tag_type column is still dropped either way, so the resulting schema is identical in both cases.

Testing

• New regression test: upgrade to 0003, drop the index to simulate the wild state, upgrade to head — previously raised ValueError, now succeeds and tag_type is gone.
• .venv/bin/python -m pytest tests-unit/app_test/test_migrations.py -q (5 passed)
• .venv/bin/python -m ruff check .

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📥 Commits

Reviewing files that changed from the base of the PR and between 14b0522 and 096bbcd.

📒 Files selected for processing (2)

• alembic_db/versions/0004_drop_tag_type.py
• tests-unit/app_test/test_migrations.py

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📓 Path-based instructions (4)

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**/*: Keep changes and file scope as small and direct as possible; prefer practical fixes, minimal dependencies, existing patterns, and removal of obsolete code.
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Files:

• alembic_db/versions/0004_drop_tag_type.py
• tests-unit/app_test/test_migrations.py

**/*.py

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Files:

• alembic_db/versions/0004_drop_tag_type.py
• tests-unit/app_test/test_migrations.py

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Files:

• alembic_db/versions/0004_drop_tag_type.py
• tests-unit/app_test/test_migrations.py

alembic_db/**

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Files:

• alembic_db/versions/0004_drop_tag_type.py

🧠 Learnings (1)

📚 Learning: 2026-02-21T14:01:41.482Z

Learnt from: pythongosssss
Repo: Comfy-Org/ComfyUI PR: 12555
File: comfy_extras/nodes_glsl.py:719-724
Timestamp: 2026-02-21T14:01:41.482Z
Learning: In PyOpenGL, bare Python scalars can be accepted for 1-element array parameters by NumberHandler. This means you can pass an int/float directly to OpenGL texture deletion (e.g., glDeleteTextures(tex)) without wrapping in a list. Verify function-specific expectations and ensure types match what the OpenGL call expects; use explicit lists only when the API requires an array.

Applied to files:

• alembic_db/versions/0004_drop_tag_type.py
• tests-unit/app_test/test_migrations.py

🔇 Additional comments (2)

alembic_db/versions/0004_drop_tag_type.py (1)

24-32: LGTM!

tests-unit/app_test/test_migrations.py (1)

54-70: LGTM!

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📝 Walkthrough

Walkthrough

The revision 0004 migration now checks whether ix_tags_tag_type exists before dropping it. The migration still removes the tag_type column. A regression test covers a SQLite database at revision 0003 with the index removed before upgrading to head.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the migration failure and the missing index condition.
Description check	✅ Passed	The description explains the migration failure, the fix, and the regression test related to the changeset.
Linked Issues check	✅ Passed	The migration conditionally drops the missing index and always removes tag_type, satisfying issue #15022.
Out of Scope Changes check	✅ Passed	The changes are limited to the migration fix and its regression test for issue #15022.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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