The legacy CFG emitted two ControlFlowNodes for `x[i] += 42` (one load,
one store, with `load.strictlyDominates(store)`). The new CFG collapses
them to a single canonical node, mirroring Java's single-`VarAccess`
model where `isVarRead`/`isVarWrite` are non-disjoint on the same
expression. Reconcile two legacy two-node behaviours with the merged
single-node world:
1. `Cfg::ControlFlowNode.isLoad()` no longer excludes augmented
targets — both `isLoad` and `isStore` hold on the merged canonical
node, matching Java. `NameNode.defines` drops the now-redundant
`not isLoad` guard; `Py::Name.defines` already filters by
`isDefinition` (Store/Param/AugAssign-target ctx).
2. `LocalFlow::definitionFlowStep` is restricted to NameNode targets,
matching legacy ESSA's `assignment_definition` which required
`defn.(NameNode).defines(v)`. Subscript and attribute writes
(`x[i] = 42`, `obj.attr = 42`) no longer emit a local-flow step
*into* the LHS expression — that flow is handled by the AttrWrite
and content-flow machinery. This is essential for keeping augmented
Subscript/Attribute targets classifiable as `LocalSourceNode` on
the read side, which the API graph requires for emitting Use edges.
`StoreLoadTest.ql` is updated to filter `isAugLoad` out of the regular
`load` tag, mirroring the pre-existing `not isAugStore` filter on the
`store` tag so augmented-assignment expectations remain
`augload=n augstore=n` (not also `load=n store=n`).
Closes the three remaining ApiGraphs library-test failures
(`getSubscript.ql` semantically, plus cosmetic toString updates in
`ModuleImportWithDots.ql` and `test_crosstalk.ql`).
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
In the legacy CFG the same Python 'Name' that is the target of an
augmented assignment has two distinct CFG nodes — a load node (context
3) earlier in the basic block and a store node (context 5) later.
'augstore(load, store)' relates the pair via dominance.
The new (shared) CFG canonicalises each AST expression to a single
CFG node, so 'load' and 'store' collapse to one. The dominance-based
'augstore' from the legacy implementation no longer holds (it would
require 'load.strictlyDominates(load)'), so 'isAugLoad' / 'isAugStore'
never fired and 'isStore' missed the AugAssign target entirely.
Redefines 'augstore' as reflexive on the AugAssign target's canonical
CFG node. With this change:
* isAugLoad / isAugStore both fire on the single canonical node.
* isStore fires (via 'or augstore(_, this)') — matching the legacy
classification that an augmented-assignment target is a store.
* isLoad does not fire (excluded by 'not augstore(_, this)').
Adds 'python/ql/test/library-tests/ControlFlow/store-load/' covering
plain load/store/delete, parameters, augmented assignment, tuple
unpacking, attribute and subscript stores. The test asserts the
classification directly on the new-CFG facade.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
