Python: Fix MatchSequence parser incorrectly consuming child's delimiter
#6713
+164
−19
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When parsing `case [c], _:`, the outer implicit tuple MatchSequence was greedily consuming the `[` that belongs to the inner child MatchSequence. This caused the pattern to be parsed as a single bracketed list `[c, _]` instead of an implicit tuple containing `[c]` and `_`. The fix adds `__is_own_sequence_delimiter` which checks whether a `[` or `(` delimiter belongs to this MatchSequence or to its first child by combining AST inspection (is the first child also a MatchSequence?) with token peeking (are there consecutive delimiters?). Also includes RPC server improvements: relativeTo path support for parse inputs, bare string PathInput handling, and better error logging.
knutwannheden
changed the title
MatchSequence parser incorrectly consuming child's delimiter
jkschneider
reviewed
Feb 10, 2026
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When parsing
case [c], _:, the outer implicit tuple MatchSequence was greedily consuming the[that belongs to the inner child MatchSequence. This caused the pattern to be parsed as a single bracketed list[c, _]instead of an implicit tuple containing[c]and_.The fix adds
__is_own_sequence_delimiterwhich checks whether a[or(delimiter belongs to this MatchSequence or to its first child by combining AST inspection (is the first child also a MatchSequence?) with token peeking (are there consecutive delimiters?).Also includes RPC server improvements: relativeTo path support for parse inputs, bare string PathInput handling, and better error logging.