From 4543c66d26ba2cd7df87869abfe32f45bd3ecbe4 Mon Sep 17 00:00:00 2001
From: Taus <tausbn@github.com>
Date: Fri, 9 Jan 2026 13:49:17 +0000
Subject: [PATCH] Python: Prepare `LocalSourceNode` for locality

Removes the dependence on the (global) `ModuleVariableNode.getARead()`,
by adding a local version (that doesn't include `import *` reads)
instead.
---
 .../python/dataflow/new/internal/DataFlowPublic.qll    | 10 +++++++---
 .../python/dataflow/new/internal/LocalSources.qll      |  4 ++--
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPublic.qll b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPublic.qll
index 4d112bcdcdd..10ac89b023d 100644
--- a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPublic.qll
+++ b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPublic.qll
@@ -440,13 +440,17 @@ class ModuleVariableNode extends Node, TModuleVariableNode {
 
   /** Gets a node that reads this variable. */
   Node getARead() {
-    result.asCfgNode() = var.getALoad().getAFlowNode() and
-    // Ignore reads that happen when the module is imported. These are only executed once.
-    not result.getScope() = mod
+    result = this.getALocalRead()
     or
     this = import_star_read(result)
   }
 
+  /** Gets a node that reads this variable, excluding reads that happen through `from ... import *`. */
+  Node getALocalRead() {
+    result.asCfgNode() = var.getALoad().getAFlowNode() and
+    not result.getScope() = mod
+  }
+
   /** Gets an `EssaNode` that corresponds to an assignment of this global variable. */
   Node getAWrite() {
     any(EssaNodeDefinition def).definedBy(var, result.asCfgNode().(DefinitionNode))
diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/LocalSources.qll b/python/ql/lib/semmle/python/dataflow/new/internal/LocalSources.qll
index c43a111c9c8..7752846ae1f 100644
--- a/python/ql/lib/semmle/python/dataflow/new/internal/LocalSources.qll
+++ b/python/ql/lib/semmle/python/dataflow/new/internal/LocalSources.qll
@@ -67,7 +67,7 @@ class LocalSourceNode extends Node {
     or
     // We explicitly include any read of a global variable, as some of these may have local flow going
     // into them.
-    this = any(ModuleVariableNode mvn).getARead()
+    this = any(ModuleVariableNode v).getALocalRead()
     or
     // We include all scope entry definitions, as these act as the local source within the scope they
     // enter.
@@ -248,7 +248,7 @@ private module Cached {
   pragma[nomagic]
   private predicate localSourceFlowStep(Node nodeFrom, Node nodeTo) {
     simpleLocalFlowStep(nodeFrom, nodeTo, _) and
-    not nodeTo = any(ModuleVariableNode v).getARead()
+    not nodeTo = any(ModuleVariableNode v).getALocalRead()
   }
 
   /**