Correctly handle ignore pattern in multilevel nested histories

[pfn-asm]

This fix covers two main topics regarding ignore patterns in nested histories:

• applying the ignore pattern in an existing nested history correctly (relative to the location of the child history)
• writing an ignore pattern supplied to the create command into the respective child histories it actually affects (if it's not a global one)

[Copilot]

Pull Request Overview

This pull request fixes the handling of ignore patterns in multilevel nested histories and ensures that patterns are correctly propagated into child histories. Key changes include:

• Enhancements in the logic to compute relevant ignore patterns in nested histories.
• Introduction of new helper functions and updates to ignore spec calculations in generator and commands.
• Updates to test fixtures to support the revised ignore pattern functionality.

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/test_ignore.py	Added a helper test function for asserting ignore pattern behavior.
tests/conftest.py	Added fixtures to simulate complex nested file structures for testing.
ascmhl/utils.py	Introduced a utility function to check if a path is absolute to a history.
ascmhl/history.py	Added method to accumulate ignore patterns from nested histories.
ascmhl/generator.py	Revised commit logic to use the new get_relevant_ignore_pattern helper.
ascmhl/commands.py	Updated ignore spec handling to incorporate nested history ignores.
.github/workflows/build+test.yml	Adjusted branch list to reflect the new feature branch.

Comments suppressed due to low confidence (1)

tests/test_ignore.py:85

• The parameter name 'pattern' is reused as the loop variable in 'for pattern in pattern:', which shadows the outer variable. Consider renaming the loop variable to avoid confusion.

def assert_pattern_ignored_in_result(pattern: [str], result, negate=False):

[Copilot]

Using 'startswith' to determine if one path is within another may lead to false positives (e.g., '/root/foo' vs '/root/foobar'). Consider using os.path.commonpath or a more robust method for path comparison.

[pfn-asm]

covered by pull request #166