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Title: Python: add new shared-CFG-backed control flow graph (additive) by yoff · Pull Request #21921 · github/codeql · GitHub

Open Graph Title: Python: add new shared-CFG-backed control flow graph (additive) by yoff · Pull Request #21921 · github/codeql

X Title: Python: add new shared-CFG-backed control flow graph (additive) by yoff · Pull Request #21921 · github/codeql

Description: Summary Preparatory refactor for the shared-CFG dataflow migration (#21894). Based on #21920 — merge that first. Adds the new Python CFG library additively, without changing any production behaviour. Library additions semmle.python.controlflow.internal.AstNodeImpl — mediates between the Python AST and the shared codeql.controlflow.ControlFlowGraph signature. Wraps Python's Stmt/Expr/Scope/Pattern and adds two synthetic kinds of node (BlockStmt for body slots, intermediate nodes for multi-operand boolean expressions). semmle.python.controlflow.internal.Cfg — public facade re-exposing the same API surface as semmle/python/Flow.qll (ControlFlowNode, CallNode, BasicBlock, NameNode, DefinitionNode, CompareNode, ...), backed by the shared CFG. Intended as a drop-in replacement for use by the upcoming dataflow migration. lib/printCfgNew.ql — debug/visualisation query for the new CFG. consistency-queries/CfgConsistency.ql — runs the shared CFG's standard structural checks against Python. Shared library shared/controlflow/.../ControlFlowGraph.qll — adds two defaulted predicates getWhileElse / getForeachElse to AstSig so Python can model while-else / for-else. The defaults are none(), so existing languages are unaffected. Test additions ControlFlow/bindings/* — annotation-driven SSA-binding tests for the new CFG (annassign, compound, comprehension, decorated, except_handler, imports, match_pattern, parameters, simple, type_params, walrus_starred, with_stmt, dead_under_no_raise). ControlFlow/store-load/* — basic store/load coverage. ControlFlow/evaluation-order/NewCfg*.ql — mirrors of the existing OldCfg evaluation-order self-validation suite, run against the new CFG via NewCfgImpl.qll. Minor extensions to existing test_if.py / test_boolean.py plus cosmetic .expected churn on a handful of OldCfg tests (to add more annotation coverage). Production impact None. No dataflow, SSA, or production query is migrated yet — that lands in follow-up PRs. The new CFG library has zero callers in lib/ and src/ after this PR. Verification All 367 lib/ + src/ + consistency-queries/ queries compile clean. All 56 ControlFlow library-tests pass. All 474 dataflow + PointsTo library-tests + consistency tests pass. syntax_error/CONSISTENCY/CfgConsistency passes. Notes for reviewers AstNodeImpl.qll is the bulk of the new code (~1.7k LOC) and is the file most worth careful review. Most of it is the AST→CFG mapping table (getChild, isExpressionNode, beginAbruptCompletion, etc.) plus the synthetic BlockStmt newtype. Cfg.qll is the facade and is mostly mechanical class-by-class shadowing of Flow.qll's public API on top of the shared library.

Open Graph Description: Summary Preparatory refactor for the shared-CFG dataflow migration (#21894). Based on #21920 — merge that first. Adds the new Python CFG library additively, without changing any production behaviou...

X Description: Summary Preparatory refactor for the shared-CFG dataflow migration (#21894). Based on #21920 — merge that first. Adds the new Python CFG library additively, without changing any production behaviou...

Opengraph URL: https://github.com/github/codeql/pull/21921

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