Merge pull request #8732 from RasmusWL/dataflow-imports

Python: Don't re-export `python` under `DataFlow::`

Author: yoff

python/ql/lib/change-notes/2022-04-20-export-python-under-DataFlow.md

@@ -0,0 +1,4 @@
+---
+ category: breaking
+---
+ * The imports made available from `import python` are no longer exposed under `DataFlow::` after doing `import semmle.python.dataflow.new.DataFlow`, for example using `DataFlow::Add` will now cause a compile error.

python/ql/lib/semmle/python/SpecialMethods.qll

@@ -8,7 +8,7 @@
  * Extend `SpecialMethod::Potential` to capture more cases.
  */
 
-import python
+private import python
 
 /** A control flow node which might correspond to a special method call. */
 class PotentialSpecialMethodCallNode extends ControlFlowNode {

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImplSpecific.qll

@@ -1,9 +1,15 @@
 /**
  * Provides Python-specific definitions for use in the data flow library.
  */
+
+// we need to export `Unit` for the DataFlowImpl* files
+private import python as Python
+
 module Private {
   import DataFlowPrivate
+
   //   import DataFlowDispatch
+  class Unit = Python::Unit;
 }
 
 module Public {

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowUtil.qll

@@ -2,6 +2,7 @@
  * Contains utility functions for writing data flow queries
  */
 
+private import python
 private import DataFlowPrivate
 import DataFlowPublic
 

python/ql/lib/semmle/python/dataflow/new/internal/LocalSources.qll

@@ -6,7 +6,7 @@
  * local tracking within a function.
  */
 
-import python
+private import python
 import DataFlowPublic
 private import DataFlowPrivate
 private import semmle.python.internal.CachedStages

python/ql/test/experimental/dataflow/qll-private-imports/README.md

@@ -0,0 +1,3 @@
+Sometimes we accidentally re-export too much from `DataFlow` such that for example we can access `Add` from `DataFlow::Add` :disappointed:
+
+This test should always FAIL to compile!

python/ql/test/experimental/dataflow/qll-private-imports/Test.expected

@@ -0,0 +1 @@
+ERROR: Could not resolve type DataFlow::Add (Test.ql:7,6-19)

python/ql/test/experimental/dataflow/qll-private-imports/Test.ql

@@ -0,0 +1,8 @@
+import python
+private import semmle.python.dataflow.new.DataFlow
+
+// Sometimes we accidentally re-export too much from `DataFlow` such that for example we can access `Add` from `DataFlow::Add` :(
+//
+// This test should always FAIL to compile!
+from DataFlow::Add this_should_not_work
+select this_should_not_work

python/ql/test/experimental/dataflow/qll-private-imports/test.py

@@ -0,0 +1 @@
+1+1