IfStatementWithIdenticalBranchesInspection: tail call heuristic

GitOrigin-RevId: 8c74e25df2a005a28f2d0e711b61b5b128ad7979

java/java-tests/testData/inspection/commonIfParts/afterLastStatementIsCallInfo.java

@@ -0,0 +1,17 @@
+// "Extract common part from 'if'" "INFORMATION"
+
+class X {
+  void foo() {
+    if (true) {
+      another(1);
+    }
+    else {
+      another(2);
+    }
+      bar();
+  }
+
+  void another(int i) {}
+
+  void bar() {}
+}

java/java-tests/testData/inspection/commonIfParts/beforeLastStatementIsCallInfo.java

@@ -0,0 +1,18 @@
+// "Extract common part from 'if'" "INFORMATION"
+
+class X {
+  void foo() {
+    if<caret> (true) {
+      another(1);
+      bar();
+    }
+    else {
+      another(2);
+      bar();
+    }
+  }
+
+  void another(int i) {}
+
+  void bar() {}
+}

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/controlflow/IfStatementWithIdenticalBranchesInspection.java

@@ -17,6 +17,7 @@ package com.siyeh.ig.controlflow;
 
 import com.intellij.codeInsight.BlockUtils;
 import com.intellij.codeInspection.*;
+import com.intellij.codeInspection.ui.SingleCheckboxOptionsPanel;
 import com.intellij.openapi.project.Project;
 import com.intellij.psi.*;
 import com.intellij.psi.codeStyle.JavaCodeStyleManager;
@@ -29,6 +30,7 @@ import org.jetbrains.annotations.Nls;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import javax.swing.*;
 import java.util.*;
 import java.util.stream.Collectors;
 
@@ -36,12 +38,21 @@ import static com.intellij.util.ObjectUtils.tryCast;
 
 // Not really with identical branches, but also common parts
 public class IfStatementWithIdenticalBranchesInspection extends AbstractBaseJavaLocalInspectionTool {
+  public boolean myHighlightWhenLastStatementIsCall = true;
+
   private static final List<IfStatementInspector> ourInspectors = new ArrayList<>(Arrays.asList(
     ImplicitElse::inspect,
     ThenElse::inspect,
     ElseIf::inspect
   ));
 
+
+  @Nullable
+  @Override
+  public JComponent createOptionsPanel() {
+    return new SingleCheckboxOptionsPanel("Highlight when last common statement is call", this, "myHighlightWhenLastStatementIsCall");
+  }
+
   @NotNull
   @Override
   public PsiElementVisitor buildVisitor(@NotNull ProblemsHolder holder, boolean isOnTheFly) {
@@ -51,7 +62,7 @@ public class IfStatementWithIdenticalBranchesInspection extends AbstractBaseJava
         PsiStatement[] thenStatements = unwrap(ifStatement.getThenBranch());
         PsiStatement[] elseStatements = unwrap(ifStatement.getElseBranch());
         for (IfStatementInspector inspector : ourInspectors) {
-          IfInspectionResult result = inspector.inspect(ifStatement, thenStatements, elseStatements, isOnTheFly);
+          IfInspectionResult result = inspector.inspect(ifStatement, thenStatements, elseStatements, isOnTheFly, myHighlightWhenLastStatementIsCall);
           if (result != null) {
             ProblemHighlightType highlightType;
             if (result.myIsWarning) {
@@ -73,7 +84,8 @@ public class IfStatementWithIdenticalBranchesInspection extends AbstractBaseJava
     @Nullable IfInspectionResult inspect(@NotNull PsiIfStatement ifStatement,
                                          @NotNull PsiStatement[] thenBranch,
                                          @NotNull PsiStatement[] elseBranch,
-                                         boolean isOnTheFly);
+                                         boolean isOnTheFly,
+                                         boolean highlightWhenLastStatementIsCall);
   }
 
   private static class IfInspectionResult {
@@ -175,7 +187,10 @@ public class IfStatementWithIdenticalBranchesInspection extends AbstractBaseJava
     private final boolean myMayChangeSemantics;
     private final boolean myIsOnTheFly;
 
-    private ExtractCommonIfPartsFix(CommonPartType type, boolean mayChangeSemantics, boolean isOnTheFly) {
+
+    private ExtractCommonIfPartsFix(CommonPartType type,
+                                    boolean mayChangeSemantics,
+                                    boolean isOnTheFly) {
       myType = type;
       myMayChangeSemantics = mayChangeSemantics;
       myIsOnTheFly = isOnTheFly;
@@ -631,7 +646,8 @@ public class IfStatementWithIdenticalBranchesInspection extends AbstractBaseJava
     @Nullable static IfInspectionResult inspect(@NotNull PsiIfStatement ifStatement,
                                          @NotNull PsiStatement[] thenBranch,
                                          @NotNull PsiStatement[] elseBranch,
-                                         boolean isOnTheFly) {
+                                         boolean isOnTheFly,
+                                                boolean highlightWhenLastStatementIsCall) {
       ImplicitElse implicitElse = from(thenBranch, elseBranch, ifStatement);
       if (implicitElse == null) return null;
       CommonPartType type = implicitElse.getType();
@@ -807,21 +823,36 @@ public class IfStatementWithIdenticalBranchesInspection extends AbstractBaseJava
       return new ThenElse(headCommonParts, tailCommonParts, mayChangeSemantics, type, substitutionTable);
     }
 
+    private static boolean isSingleCallTail(List<PsiStatement> tail) {
+      if (tail.size() != 1) return false;
+      PsiExpressionStatement expressionStatement = tryCast(tail.get(0), PsiExpressionStatement.class);
+      if (expressionStatement == null) return false;
+      PsiMethodCallExpression call = tryCast(expressionStatement.getExpression(), PsiMethodCallExpression.class);
+      return call != null;
+    }
+
 
     @Nullable static IfInspectionResult inspect(@NotNull PsiIfStatement ifStatement,
                                                 @NotNull PsiStatement[] thenBranch,
                                                 @NotNull PsiStatement[] elseBranch,
-                                                boolean isOnTheFly) {
+                                                boolean isOnTheFly,
+                                                boolean highlightWhenLastStatementIsCall) {
       ThenElse thenElse = from(ifStatement, thenBranch, elseBranch, isOnTheFly);
       if (thenElse == null) return null;
       boolean isNotInCodeBlock = !(ifStatement.getParent() instanceof PsiCodeBlock);
       boolean mayChangeSemantics = thenElse.myMayChangeSemantics;
       CommonPartType type = thenElse.myCommonPartType;
       ExtractCommonIfPartsFix fix = new ExtractCommonIfPartsFix(type, mayChangeSemantics, isOnTheFly);
-      boolean isInfoLevel = mayChangeSemantics || isNotInCodeBlock;
+      boolean tailStatementIsSingleCall = !highlightWhenLastStatementIsCall
+                                          && isSingleCallTail(thenElse.myTailStatementsOfThen)
+                                          && thenElse.myHeadUnitsOfThen.isEmpty();
+      boolean isInfoLevel = mayChangeSemantics
+                            || isNotInCodeBlock
+                            || type == CommonPartType.WITH_VARIABLES_EXTRACT
+                            || tailStatementIsSingleCall;
       PsiElement elementToHighlight = isInfoLevel ? ifStatement : ifStatement.getFirstChild();
       if (type == CommonPartType.VARIABLES_ONLY && !isOnTheFly) return null;
-      return new IfInspectionResult(elementToHighlight, type != CommonPartType.WITH_VARIABLES_EXTRACT && !isInfoLevel, fix,
+      return new IfInspectionResult(elementToHighlight, !isInfoLevel, fix,
                                     type.getDescriptionMessage(mayChangeSemantics));
     }
 
@@ -1038,7 +1069,8 @@ public class IfStatementWithIdenticalBranchesInspection extends AbstractBaseJava
     @Nullable static IfInspectionResult inspect(@NotNull PsiIfStatement ifStatement,
                                                 @NotNull PsiStatement[] thenBranch,
                                                 @NotNull PsiStatement[] elseBranch,
-                                                boolean isOnTheFly) {
+                                                boolean isOnTheFly,
+                                                boolean highlightWhenLastStatementIsCall) {
       ElseIf elseIf = from(ifStatement, thenBranch);
       if (elseIf == null) return null;
       String message = InspectionsBundle.message("inspection.common.if.parts.family.else.if.description");

plugins/InspectionGadgets/testsrc/com/siyeh/ig/controlflow/IfStatementWithIdenticalBranchesInspectionTest.java

@@ -10,6 +10,7 @@ public class IfStatementWithIdenticalBranchesInspectionTest extends LightQuickFi
   @Override
   protected LocalInspectionTool[] configureLocalInspectionTools() {
     IfStatementWithIdenticalBranchesInspection inspection = new IfStatementWithIdenticalBranchesInspection();
+    inspection.myHighlightWhenLastStatementIsCall = !getTestName(false).equals("LastStatementIsCallInfo.java");
     return new LocalInspectionTool[]{inspection};
   }