From a8f1480bac3dc8c7786d78c48b58b5a6a1c22ee4 Mon Sep 17 00:00:00 2001
From: Bas Leijdekkers <basleijdekkers@gmail.com>
Date: Wed, 14 Feb 2024 23:57:12 +0100
Subject: [PATCH] [java] handle empty statements in "'if' statement with
 identical branches" quick fix (IDEA-233980)

GitOrigin-RevId: 388e5c5195bda88b61526f0a393ed9d81ec18830
---
 ...tementWithIdenticalBranchesInspection.java | 45 ++++++++++++++-----
 .../commonIfParts/afterEmptyStatements.java   | 15 +++++++
 .../commonIfParts/beforeEmptyStatements.java  | 17 +++++++
 3 files changed, 65 insertions(+), 12 deletions(-)
 create mode 100644 java/java-tests/testData/inspection/commonIfParts/afterEmptyStatements.java
 create mode 100644 java/java-tests/testData/inspection/commonIfParts/beforeEmptyStatements.java

diff --git a/java/java-analysis-impl/src/com/siyeh/ig/controlflow/IfStatementWithIdenticalBranchesInspection.java b/java/java-analysis-impl/src/com/siyeh/ig/controlflow/IfStatementWithIdenticalBranchesInspection.java
index 9577771a01dc..bad06af8cf8d 100644
--- a/java/java-analysis-impl/src/com/siyeh/ig/controlflow/IfStatementWithIdenticalBranchesInspection.java
+++ b/java/java-analysis-impl/src/com/siyeh/ig/controlflow/IfStatementWithIdenticalBranchesInspection.java
@@ -366,17 +366,38 @@ public final class IfStatementWithIdenticalBranchesInspection extends AbstractBa
         }
         PsiStatement[] thenStatements = ControlFlowUtils.unwrapBlock(ifStatement.getThenBranch());
         PsiStatement[] elseStatements = ControlFlowUtils.unwrapBlock(ifStatement.getElseBranch());
-        int thenLength = thenStatements.length;
-        int elseLength = elseStatements.length;
-        for (int i = 0; i < tailStatements.size(); i++) {
-          PsiStatement thenStatement = thenStatements[thenLength - 1 - i];
-          // handling situation, when there is no braces around then branch
-          if (thenStatements.length == 1 && thenStatement.getParent() == ifStatement) {
-            thenStatement.replace(JavaPsiFacade.getElementFactory(thenStatement.getProject()).createCodeBlock());
-          } else {
-            thenStatement.delete();
+        for (int i = thenStatements.length - 1; i >= 0; i--) {
+          PsiStatement statement = thenStatements[i];
+          if (!(statement instanceof PsiEmptyStatement)) break;
+          //emptyStatementCount++;
+        }
+        if (thenStatements.length == 1 && thenStatements[0].getParent() == ifStatement) {
+          thenStatements[0].replace(JavaPsiFacade.getElementFactory(ifStatement.getProject()).createCodeBlock());
+        }
+        else {
+          deleteStatements(thenStatements, tailStatements.size(), ct, false);
+        }
+        deleteStatements(elseStatements, tailStatements.size(), ct, true);
+      }
+    }
+
+    private static void deleteStatements(PsiStatement[] statements, int count, CommentTracker ct, boolean keepComments) {
+      for (int i = statements.length - 1; i >= 0; i--) {
+        PsiStatement statement = statements[i];
+        if (statement instanceof PsiEmptyStatement) {
+          ct.delete(statement);
+        }
+        else if (count > 0) {
+          count--;
+          if (keepComments) {
+            ct.delete(statement);
           }
-          ct.delete(elseStatements[elseLength - 1 - i]);
+          else {
+            statement.delete();
+          }
+        }
+        else {
+          break;
         }
       }
     }
@@ -776,12 +797,12 @@ public final class IfStatementWithIdenticalBranchesInspection extends AbstractBa
     final Map<PsiLocalVariable, String> mySubstitutionTable;
 
     private ThenElse(List<ExtractionUnit> headUnitsOfThen,
-                     List<PsiStatement> tailUnitsOfThen,
+                     List<PsiStatement> tailStatementsOfThen,
                      boolean mayChangeSemantics,
                      CommonPartType commonPartType,
                      Map<PsiLocalVariable, String> substitutionTable) {
       myHeadUnitsOfThen = headUnitsOfThen;
-      myTailStatementsOfThen = tailUnitsOfThen;
+      myTailStatementsOfThen = tailStatementsOfThen;
       myMayChangeSemantics = mayChangeSemantics;
       myCommonPartType = commonPartType;
       mySubstitutionTable = substitutionTable;
diff --git a/java/java-tests/testData/inspection/commonIfParts/afterEmptyStatements.java b/java/java-tests/testData/inspection/commonIfParts/afterEmptyStatements.java
new file mode 100644
index 000000000000..e34fc9b79d69
--- /dev/null
+++ b/java/java-tests/testData/inspection/commonIfParts/afterEmptyStatements.java
@@ -0,0 +1,15 @@
+// "Extract common part removing branch" "true"
+
+class EmptyStatements {
+
+  private void refactor() {
+    if (new java.util.Random().nextBoolean()) {
+      foo();
+    }
+      bar();
+  }
+
+  private void foo() {}
+
+  private void bar() {}
+}
\ No newline at end of file
diff --git a/java/java-tests/testData/inspection/commonIfParts/beforeEmptyStatements.java b/java/java-tests/testData/inspection/commonIfParts/beforeEmptyStatements.java
new file mode 100644
index 000000000000..b9c3145c3e2f
--- /dev/null
+++ b/java/java-tests/testData/inspection/commonIfParts/beforeEmptyStatements.java
@@ -0,0 +1,17 @@
+// "Extract common part removing branch" "true"
+
+class EmptyStatements {
+
+  private void refactor() {
+    if<caret> (new java.util.Random().nextBoolean()) {
+      foo();
+      ;;bar();;;;
+    } else {
+      bar();;
+    }
+  }
+
+  private void foo() {}
+
+  private void bar() {}
+}
\ No newline at end of file