Fix #2528: Handle isort: off/on comments with and without spaces

[harshith-coder]

Description

Fixes #2528: Handle isort: off and isort: on comments with and without spaces

Root Cause

The comment detection in core.py was using exact string matching (e.g., stripped_line == "# isort: off"), which only worked with specific spacing. Comments like #isort: off or # isort:off were not recognized, causing imports to be sorted despite the directive.

Changes Made

• Modified isort/core.py to use flexible string matching for comment detection
• Updated 4 locations to check if "isort: off" or "isort:off" is in the line, rather than exact equality
• Added comprehensive regression tests in test_action_comments.py

Files Changed

• isort/core.py (lines 93, 99, 181, 236)
• tests/unit/test_action_comments.py (new test function with 6 test cases)

Testing

• All 311 existing tests pass
• New regression test covers:
  • Plain imports with isort: off
  • From imports with isort: off
  • Mixed import types with isort: off
  • Comment variations: #isort: off, # isort:off, # isort: off
  • Toggle behavior with isort: on

Verification

# Before fix: imports below were SORTED (bug!)
#isort: off
import z
import a
import b

# After fix: imports below are PRESERVED (correct!)
#isort: off
import z
import a
import b

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.15%. Comparing base (0351f0e) to head (d4131a5).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2544   +/-   ##
=======================================
  Coverage   99.15%   99.15%           
=======================================
  Files          41       41           
  Lines        3094     3094           
  Branches      669      669           
=======================================
  Hits         3068     3068           
  Misses         14       14           
  Partials       12       12           

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[DanielNoord]

This does not the fix the linked issue.

[harshith-coder]

Hi @DanielNoord,

Thank you for reviewing the PR. I understand you mentioned this doesn't fix the linked issue #2528.

I'd appreciate clarification on what aspect of issue #2528 is not being addressed. Based on my investigation, the fix I submitted handles the case where isort: off comments without proper spacing (like #isort: off or # isort:off) were not being recognized and imports were being sorted despite the directive.

I tested the fix with:

test_code = """#isort: off
import z
import a
import b
"""
result = isort.code(test_code)
# Result: imports remain unsorted ✓