fix: preserve duplicate keyword delimiter matches

[aiedwardyi]

Follows up on the duplicate-keyword-start bug reported on #281.

What changed

• preserve all delimiters that share the same keyword start instead of collapsing them to the last map entry
• deduplicate regex alternation inputs without changing per-delimiter behavior
• add a regression test covering duplicate keyword starts

Validation

• direct execution of _match_keyword_delimiters() in an isolated env returned both STRUCT and TYPE_ALIAS matches for the same type keyword
• py_compile passed for the touched files

Note

I don't have push access to the original bolt-optimize-chunker-delimiter-7248057790755398651 branch, so this follow-up PR carries the minimal fix needed to make that optimization mergeable.

Summary by Sourcery

Preserve behavior for duplicate keyword-start delimiters while keeping the optimized single-regex matching path.

Bug Fixes:

• Ensure keyword delimiters sharing the same start string all produce matches instead of collapsing to the last delimiter.

Enhancements:

• Optimize keyword delimiter matching by using a single combined regex with deduplicated start strings and grouping delimiters by keyword.
• Return early from keyword matching when no non-empty-start keyword delimiters are present.
• Fix a minor spelling issue in the custom delimiter loading docstring.

Tests:

• Add a regression test ensuring duplicate keyword starts preserve all corresponding delimiter matches.

[sourcery-ai]

Reviewer's Guide

Optimizes and corrects keyword delimiter matching so that duplicate keyword start strings preserve all associated delimiters, while adding a regression test and a minor docstring typo fix.

Sequence diagram for optimized keyword delimiter matching

sequenceDiagram
    participant Caller as Chunker
    participant M as _match_keyword_delimiters
    participant R as re
    participant S as _is_inside_string_or_comment
    participant F as _find_next_structural_with_char

    Caller->>M: _match_keyword_delimiters(content, keyword_delimiters, matches)
    M->>M: Filter keyword_delimiters where d.start is truthy
    alt no keyword_delimiters
        M-->>Caller: return matches
    else keyword_delimiters present
        M->>R: compile combined_pattern from unique delimiter.start values
        M->>M: Build delimiter_map[start_string] -> list[Delimiter]
        loop for each match in combined_pattern.finditer(content)
            M->>R: combined_pattern.finditer(content)
            R-->>M: match with matched_text and keyword_pos
            M->>S: _is_inside_string_or_comment(content, keyword_pos)
            S-->>M: bool is_inside
            alt is_inside
                M->>M: continue to next match
            else not inside
                loop for each delimiter in delimiter_map[matched_text]
                    M->>F: _find_next_structural_with_char(content, keyword_pos, structural_pairs)
                    F-->>M: struct_start, struct_char
                    M->>M: Evaluate delimiter rules and update matches
                end
            end
        end
        M-->>Caller: return matches
    end

Loading

File-Level Changes

Change	Details	Files
Preserve all delimiters when multiple keyword delimiters share the same start string while using a single optimized regex scan.	Short-circuit and return early when the filtered keyword delimiter list is empty. Build a de-duplicated list of keyword start strings and compile a single combined regex pattern using word boundaries and escaped starts. Create a mapping from each start string to its list of corresponding Delimiter objects to handle duplicates. Iterate over matches from the combined regex, skip those inside strings or comments, then apply the original structural matching logic for every delimiter associated with the matched start text.	src/codeweaver/engine/chunker/delimiter.py
Add regression coverage for duplicate keyword start delimiters and import necessary test dependencies.	Introduce a new unit test that defines two Delimiter instances with the same 'type' start but different kinds and asserts both matches are returned. Import DelimiterKind and Delimiter in the test module to construct the test delimiters.	tests/unit/engine/chunker/test_delimiter_edge_cases.py
Fix a minor spelling issue in a docstring parameter description.	Change 'normalised' to 'normalized' in the _load_custom_delimiters docstring parameter description.	src/codeweaver/engine/chunker/delimiter.py

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[github-actions]

👋 Hey @aiedwardyi,

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[Copilot]

Pull request overview

Fixes the regression introduced by the single-regex keyword matching optimization so that multiple delimiters sharing the same keyword start are all preserved (instead of being overwritten), and adds a regression test for the duplicate-keyword-start case reported in #281.

Changes:

• Update _match_keyword_delimiters() to group keyword delimiters by start and emit matches for all delimiters that share a matched keyword.
• Deduplicate keyword start strings when building the combined regex alternation to avoid repeated alternation entries.
• Add a unit regression test ensuring duplicate keyword starts (e.g., type) return multiple delimiter matches.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/codeweaver/engine/chunker/delimiter.py	Preserves all delimiters for duplicate keyword starts by mapping matched text to a list of delimiters; also avoids compiling an empty/degenerate combined pattern after filtering.
tests/unit/engine/chunker/test_delimiter_edge_cases.py	Adds regression coverage asserting duplicate keyword starts produce multiple matches with distinct DelimiterKinds.

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[codecov]

Codecov Report

❌ Patch coverage is 91.66667% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/codeweaver/engine/chunker/delimiter.py	91.66%	1 Missing ⚠️

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[bashandbone]

Thanks for the PR @aiedwardyi -- merging. I'll close #281