PY-1244 "Unreachable code" false positive with try/except/else/finally

python/src/com/jetbrains/python/codeInsight/controlflow/PyControlFlowBuilder.java

@@ -497,16 +497,16 @@ public class PyControlFlowBuilder extends PyRecursiveElementVisitor {
         }
 
         // handle return pending instructions inside try if final block exists
-        if (!finallyRef.isNull() &&
-            PsiTreeUtil.isAncestor(tryPart, pendingElement, false)) {
+        final boolean isPending = PsiTreeUtil.isAncestor(node, pendingElement, false) &&
+                                  (finallyPart == null || !PsiTreeUtil.isAncestor(finallyPart, pendingElement, false));
+        if (!finallyRef.isNull() && isPending) {
           myBuilder.addEdge(instruction, finallyRef.get());
           myBuilder.addPendingEdge(null, lastFinallyRef.get());
           return;
         }
 
         // Handle pending instructions inside try with final block
-        if (finallyPart!=null && pendingScope !=finallyPart &&
-            PsiTreeUtil.isAncestor(tryPart, pendingElement, false)) {
+        if (finallyPart!=null && pendingScope !=finallyPart && isPending) {
           myBuilder.addEdge(instruction, finallyRef.get());
           return;
         }

python/testData/codeInsight/controlflow/tryexceptelsefinally.py

@@ -0,0 +1,9 @@
+d = dict()
+try:
+    v = d['key']
+except KeyError:
+    print 'element not found'
+else:
+    print 'element value {0}'.format(v)
+finally:
+    print 'excuting finally clause'

python/testData/codeInsight/controlflow/tryexceptelsefinally.txt

@@ -0,0 +1,19 @@
+0(1) element: null
+1(2) element: PyAssignmentStatement
+2(3) READ ACCESS: dict
+3(4) WRITE ACCESS: d
+4(5) element: PyTryExceptStatement
+5(6) element: PyTryPart
+6(7) element: PyAssignmentStatement
+7(8) element: PySubscriptionExpression
+8(9) READ ACCESS: d
+9(10,13) WRITE ACCESS: v
+10(11) element: PyElsePart
+11(12) element: PyPrintStatement
+12(16) READ ACCESS: v
+13(14) element: PyExceptPart
+14(15) READ ACCESS: KeyError
+15(16) element: PyPrintStatement
+16(17) element: PyFinallyPart
+17(18) element: PyPrintStatement
+18() element: null

python/testSrc/com/jetbrains/python/PyControlFlowBuilderTest.java

@@ -119,6 +119,10 @@ public class PyControlFlowBuilderTest extends LightMarkedTestCase {
     doTest();
   }
 
+  public void testTryExceptElseFinally() throws Exception {
+    doTest();
+  }
+
   public void testTryFinally() throws Exception {
     doTest();
   }