PY-579

Incorrect "code is unreachable" warning

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

@@ -3,6 +3,8 @@ package com.jetbrains.python.codeInsight.controlflow;
 import com.intellij.codeInsight.controlflow.ControlFlowBuilder;
 import com.intellij.codeInsight.controlflow.ControlFlow;
 import com.intellij.codeInsight.controlflow.Instruction;
+import com.intellij.codeInsight.controlflow.impl.InstructionImpl;
+import com.intellij.openapi.util.Pair;
 import com.intellij.openapi.util.Ref;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.util.PsiTreeUtil;
@@ -12,6 +14,7 @@ import com.jetbrains.python.psi.impl.PyImportStatementNavigator;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * @author oleg
@@ -259,10 +262,7 @@ public class PyControlFlowBuilder extends PyRecursiveElementVisitor {
     myBuilder.prevInstruction = head;
     if (elsePart != null) {
       elsePart.accept(this);
-      myBuilder.addPendingEdge(node, myBuilder.prevInstruction); // exit
-    }
-    else {
-      myBuilder.addPendingEdge(null, myBuilder.prevInstruction);
+      myBuilder.addPendingEdge(node, myBuilder.prevInstruction);
     }
     myBuilder.flowAbrupted();
   }
@@ -346,14 +346,21 @@ public class PyControlFlowBuilder extends PyRecursiveElementVisitor {
     }
 
     final ArrayList<Instruction> exceptInstructions = new ArrayList<Instruction>();
+    // Store pending and clear it
+    final List<Pair<PsiElement, Instruction>> myPending = myBuilder.pending;
+    myBuilder.pending = new ArrayList<Pair<PsiElement, Instruction>>();
     for (PyExceptPart exceptPart : node.getExceptParts()) {
       myBuilder.prevInstruction = lastBlockInstruction;
-      final Instruction exceptInstruction = myBuilder.startNode(exceptPart);
+      final Instruction exceptInstruction = new InstructionImpl(myBuilder, exceptPart);
+      myBuilder.addNode(exceptInstruction);
       exceptInstructions.add(exceptInstruction);
       exceptPart.accept(this);
       myBuilder.addPendingEdge(node, myBuilder.prevInstruction);
     }
-
+    // Restore pending
+    for (Pair<PsiElement, Instruction> pair : myPending) {
+      myBuilder.addPendingEdge(pair.first, pair.second);
+    }
     final PyFinallyPart finallyPart = node.getFinallyPart();
     Instruction finallyInstruction = null;
     Instruction lastFinallyInstruction = null;

python/src/com/jetbrains/python/psi/PyForStatement.java

@@ -22,8 +22,7 @@ import org.jetbrains.annotations.Nullable;
 /**
  * The 'for/else' statement.
  */
-public interface PyForStatement extends PyStatement, NameDefiner {
+public interface PyForStatement extends PyLoopStatement, NameDefiner {
   @NotNull PyForPart getForPart();
   @Nullable PyElsePart getElsePart();
-
 }

python/testData/codeInsight/controlflow/trybreak.py

@@ -0,0 +1,7 @@
+def foo():
+    try:
+        for i in bar:
+            break
+    except:
+        raise Exception()
+    return 3

python/testData/codeInsight/controlflow/trybreak.txt

@@ -0,0 +1,12 @@
+0(1) element: null
+1(2) element: PyTryExceptStatement
+2(3) element: PyTryPart
+3(4) element: PyForStatement
+4(5,10) READ ACCESS: bar
+5(6) element: PyStatementList
+6(7) WRITE ACCESS: i
+7(10) element: PyBreakStatement
+8(9) element: PyExceptPart
+9(11) element: PyRaiseStatement
+10(11) element: PyReturnStatement
+11() element: null

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

@@ -82,6 +82,14 @@ public class PyControlFlowBuilderTest extends LightMarkedTestCase {
     doTest();
   }
 
+  public void testTryBreak() throws Exception {
+    final String testName = getTestName(false).toLowerCase();
+    configureByFile(testName + ".py");
+    final ControlFlow flow = ((PyFunction)((PyFile)myFile).getStatements().get(0)).getControlFlow();
+    final String fullPath = getTestDataPath() + testName + ".txt";
+    check(fullPath, flow);
+  }
+
   public void testFunction() throws Exception {
     final String testName = getTestName(false).toLowerCase();
     configureByFile(testName + ".py");