[CLCK0622]

With git diff --no-prefix, is_rename unconditionally discards the first two filename characters, so a rename such as a.py to b.py goes undetected and path returns the source filename. Remove surrounding quotes for comparison and discard two characters only when both resulting paths start with a character followed by /; this retains custom prefixes such as x/ and y/. For equally quoted inputs, comparisons with two such prefixes remain equivalent to the original behavior; otherwise, results change only when the original strings differ but become equal after discarding their first two characters. This follows the target-path behavior discussed in #77 and implemented in #79. A no-prefix rename where both real directory names resemble single-character prefixes, such as a/x.py to b/x.py, remains ambiguous from the header and is unchanged.

Reproduce with an installed checkout:

python - <<'PY'
from unidiff import PatchSet

diff = """diff --git a.py b.py
similarity index 100%
rename from a.py
rename to b.py
"""
patched = PatchSet(diff)[0]
print(patched.is_rename, patched.path, patched.source_file, patched.target_file)
PY

Version	Output
Before	False a.py a.py b.py
After	True b.py a.py b.py

Validation on macOS arm64:

• Python 3.12.13 and 3.9.6: python -m unittest discover -s tests/ passes 72 tests (69 on the unchanged baseline); applying only the added tests produces 14 expected failures.
• python -m mypy unidiff/ with mypy 2.4.0 on Python 3.12: no issues in 6 source files before and after.
• Also checked against diffs generated by git diff with the default, --no-prefix, mnemonic, and custom --src-prefix/--dst-prefix settings; only no-prefix names that differ in their first two characters change.

The upstream CI matrix has not been run locally.

Manually written headers that quote only one side of otherwise equivalent filenames change from renames to non-renames; Git does not generate such output.

AI disclosure: Codex assisted with part of the code and this description.

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