Fix patchedast aborting on ''' inside a double-quoted f-string

[marlon-costa-dc]

Description

patchedast._JoinedStr.end_quote_char() selects the closing delimiter by max(len(quote)) over every quote character found anywhere in the f-string body. When a ''' sequence appears inside a double-quoted f-string, e.g.:

f"cfg = '''\n{value}"

the ''' in the body is picked as the delimiter instead of the actual closing ". That produces a reconstructed token that consume_joined_string() cannot locate, raising:

ValueError: substring not found

which surfaces as MismatchedTokenError and aborts rename / inline for the entire module — a single such f-string anywhere in a project breaks refactoring of that file.

Root cause

end_quote_char() chose the quote by length precedence rather than by which delimiter the f-string literally ends with. The opening quote (start_quote_char) was already correct; the closing detection was not symmetric.

Fix

Pick the delimiter the f-string literally ends with. QUOTE_CHARS is ordered longest-first (""", ''', ", '), so triple-quoted strings are still matched before single-character quotes, and the closing quote now always matches the opening one regardless of quote characters in the body.

Reproducer (before the fix)

import ast
from rope.refactor import patchedast
patchedast.patch_ast(ast.parse('f"a = \'\'\'{y}"\n'), 'f"a = \'\'\'{y}"\n')
# ValueError: substring not found

Testing

• New regression test test_handling_format_strings_with_triple_quote_in_body in ropetest/refactor/patchedasttest.py (red before, green after).
• Full suites green: ropetest/refactor/ = 944 passed, 7 skipped, 1 xfailed.
• patchedasttest.py = 141 passed, 6 skipped.

Checklist

• I have added tests that prove my fix is effective
• I have updated CHANGELOG.md
• I have made corresponding changes to user documentation for new features (n/a — bug fix)
• I have made corresponding changes to library documentation for API changes (n/a — no API change)

[Copilot]

Pull request overview

Fixes patchedast f-string reconstruction when the f-string body contains quote sequences (notably ''') that previously confused _JoinedStr.end_quote_char(), causing consume_joined_string() failures and aborting refactorings for the whole module.

Changes:

• Update _JoinedStr.end_quote_char() to select the closing delimiter based on what the source literally ends with (rather than the longest quote found in the body).
• Add a regression test covering a double-quoted f-string containing ''' inside its body.
• Document the fix in CHANGELOG.md.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
rope/refactor/patchedast.py	Fixes f-string closing delimiter detection to avoid mismatches caused by quote sequences in the f-string body.
ropetest/refactor/patchedasttest.py	Adds a regression test proving the bug and preventing future regressions.
CHANGELOG.md	Notes the bug fix and its impact on refactorings.

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