Merge pull request #6283 from tausbn/python-fix-exceptstmt-gettype

Python: Fix `ExceptStmt::getType`

Author: RasmusWL

python/ql/lib/semmle/python/Stmts.qll

@@ -153,6 +153,12 @@ class ExceptStmt extends ExceptStmt_ {
   override Stmt getASubStatement() { result = this.getAStmt() }
 
   override Stmt getLastStatement() { result = this.getBody().getLastItem().getLastStatement() }
+
+  override Expr getType() {
+    result = super.getType() and not result instanceof Tuple
+    or
+    result = super.getType().(Tuple).getAnElt()
+  }
 }
 
 /** An assert statement, such as `assert a == b, "A is not equal to b"` */

python/ql/test/query-tests/Exceptions/generators/test.py

@@ -53,3 +53,12 @@ def ok5(seq):
 
 def ok6(seq):
     yield next(iter([]), default='foo')    
+
+# Handling for multiple exception types, one of which is `StopIteration`
+# Reported as a false positive in github/codeql#6227
+def ok7(seq, ctx):
+    try:
+        with ctx:
+            yield next(iter)
+    except (StopIteration, MemoryError):
+        return