SONARPY-398 S1763: Fix FP on dead code after with statement

python-checks/src/main/java/org/sonar/python/checks/AfterJumpStatementCheck.java

@@ -58,7 +58,7 @@ private static void checkCfg(@Nullable ControlFlowGraph cfg, SubscriptionContext
           .filter(block -> cfgBlock.equals(block.syntacticSuccessor()))
           .map(block -> block.elements().get(block.elements().size() - 1))
           .collect(Collectors.toList());
-        if (isInsideFinallyClause(firstElement) || jumpStatements.stream().anyMatch(AfterJumpStatementCheck::isRaiseInsideWithStatement)) {
+        if (isInsideFinallyClause(firstElement)) {
           continue;
         }
         Tree lastElement = cfgBlock.elements().get(cfgBlock.elements().size() - 1);
@@ -68,12 +68,6 @@ private static void checkCfg(@Nullable ControlFlowGraph cfg, SubscriptionContext
     }
   }
 
-  // To avoid FP, we assume that exception raised inside with statement will be suppressed by __exit__() method of Context Manager
-  // see https://docs.python.org/3/reference/compound_stmts.html#the-with-statement
-  private static boolean isRaiseInsideWithStatement(Tree element) {
-    return element.is(Kind.RAISE_STMT) && TreeUtils.firstAncestorOfKind(element, Kind.WITH_STMT) != null;
-  }
-
   // due to CFG limitation on jump statements inside try blocks, we exclude finally clause to avoid FP.
   // TODO: After SONARPY-448 is implemented, we should remove this exclusion
   private static boolean isInsideFinallyClause(Tree element) {

python-checks/src/test/resources/checks/afterJumpStatement.py

@@ -176,3 +176,8 @@ def while_dead_code_in_else_clause_condition_true(x):
     else:
         print('dead code!') # FN, we don't take into account while condition being always true
     print("end of loop")
+
+def code_after_with():
+    with A():
+        return e
+    return False

python-squid/src/main/java/org/sonar/python/cfg/ControlFlowGraphBuilder.java

@@ -129,7 +129,7 @@ private PythonCfgBlock build(List<Statement> statements, PythonCfgBlock successo
   private PythonCfgBlock build(Statement statement, PythonCfgBlock currentBlock) {
     switch (statement.getKind()) {
       case WITH_STMT:
-        return build(((WithStatement) statement).statements().statements(), currentBlock);
+        return buildWithStatement((WithStatement) statement, currentBlock);
       case CLASSDEF:
         return build(((ClassDef) statement).body().statements(), currentBlock);
       case RETURN_STMT:
@@ -155,6 +155,13 @@ private PythonCfgBlock build(Statement statement, PythonCfgBlock currentBlock) {
     return currentBlock;
   }
 
+  private PythonCfgBlock buildWithStatement(WithStatement withStatement, PythonCfgBlock successor) {
+    PythonCfgBlock withBodyBlock = build(withStatement.statements().statements(), createSimpleBlock(successor));
+    // exceptions may be raised inside with block and be caught by context manager
+    // see https://docs.python.org/3/reference/compound_stmts.html#the-with-statement
+    return createBranchingBlock(withStatement, withBodyBlock, successor);
+  }
+
   private PythonCfgBlock tryStatement(TryStatement tryStatement, PythonCfgBlock successor) {
     PythonCfgBlock finallyOrAfterTryBlock = successor;
     FinallyClause finallyClause = tryStatement.finallyClause();

python-squid/src/test/java/org/sonar/plugins/python/api/cfg/ControlFlowGraphTest.java

@@ -407,9 +407,9 @@ public void raise_in_try() {
   @Test
   public void with_statement() {
     verifyCfg(
-      "before(succ = [if_body, END])",
+      "before(succ = [with_block, END])",
       "with A() as a:",
-      "  if cond:",
+      "  if with_block(succ = [if_body, END]):",
       "    if_body(succ = [END])"
     );
   }