[pysrc2cpg] Lower match pattern bindings into proper AST assignments#5918
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allsmog wants to merge 1 commit into
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[pysrc2cpg] Lower match pattern bindings into proper AST assignments#5918allsmog wants to merge 1 commit into
allsmog wants to merge 1 commit into
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Replaces the string-only pattern representation in match/case blocks with proper AST nodes that encode destructuring semantics, enabling data flow tracking through pattern-bound variables. For each match pattern type, generate assignment nodes using the same index access and assignment primitives as tuple unpacking: - MatchSequence [a, b]: a = subject[0], b = subject[1] - MatchAs (catch-all): x = subject - MatchAs (alias): recurse + whole = subject - MatchMapping: name = subject[key] - MatchClass: positional index + keyword field access - MatchOr: process first alternative (all bind same names) - MatchStar: rest = subject (simplified flow) - Complex subjects: temp variable to avoid re-evaluation JumpTarget nodes are preserved for CfgCreator compatibility. Nested patterns use temp variables like tuple unpacking does.
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Follow-up to the discussion in #5910 where the reviewer correctly noted that bare pattern variables as statements don't encode the destructuring semantics.
This PR lowers match patterns into assignment nodes using the same index access and assignment primitives that tuple unpacking already uses (
createIndexAccess,createAssignmentToIdentifier,getUnusedName).Lowering examples
case [a, b]:a = subject[0],b = subject[1]case x:(catch-all)x = subjectcase [a, b] as whole:whole = subjectcase {"key": val}:val = subject[key]case Point(x=a, y=b):a = subject.x,b = subject.ycase 42:/case _:JumpTarget nodes are preserved for CfgCreator compatibility. Nested patterns use temp variables following the same convention as nested tuple unpacking in
createValueToTargetsDecomposition.Test plan