InlineEdit: Report same commit message error to client

Change-Id: Iabacdf49351f0430629b7ab4de53a2c1e7b9f9c8

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/edit/ChangeEditIT.java

@@ -45,6 +45,7 @@ import com.google.gerrit.server.change.FileContentUtil;
 import com.google.gerrit.server.edit.ChangeEdit;
 import com.google.gerrit.server.edit.ChangeEditModifier;
 import com.google.gerrit.server.edit.ChangeEditUtil;
+import com.google.gerrit.server.edit.UnchangedCommitMessageException;
 import com.google.gerrit.server.project.InvalidChangeOperationException;
 import com.google.gwtorm.server.SchemaFactory;
 import com.google.inject.Inject;
@@ -247,8 +248,8 @@ public class ChangeEditIT extends AbstractDaemonTest {
       modifier.modifyMessage(
           edit.get(),
           edit.get().getEditCommit().getFullMessage());
-      fail("InvalidChangeOperationException expected");
-    } catch (InvalidChangeOperationException ex) {
+      fail("UnchangedCommitMessageException expected");
+    } catch (UnchangedCommitMessageException ex) {
       assertThat(ex.getMessage()).isEqualTo(
           "New commit message cannot be same as existing commit message");
     }

gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeEdits.java

@@ -44,6 +44,7 @@ import com.google.gerrit.server.edit.ChangeEdit;
 import com.google.gerrit.server.edit.ChangeEditJson;
 import com.google.gerrit.server.edit.ChangeEditModifier;
 import com.google.gerrit.server.edit.ChangeEditUtil;
+import com.google.gerrit.server.edit.UnchangedCommitMessageException;
 import com.google.gerrit.server.patch.PatchListNotAvailableException;
 import com.google.gerrit.server.project.InvalidChangeOperationException;
 import com.google.gerrit.server.project.NoSuchChangeException;
@@ -372,6 +373,11 @@ public class ChangeEdits implements
     @Override
     public Response<?> apply(ChangeEditResource rsrc, Input input)
         throws AuthException, ResourceConflictException, IOException {
+      String path = rsrc.getPath();
+      if (Strings.isNullOrEmpty(path) || path.charAt(0) == '/') {
+        throw new ResourceConflictException("Invalid path: " + path);
+      }
+
       try {
         editModifier.modifyFile(
             rsrc.getChangeEdit(),
@@ -474,7 +480,12 @@ public class ChangeEdits implements
         throw new BadRequestException("commit message must be provided");
       }
 
-      editModifier.modifyMessage(edit.get(), input.message);
+      try {
+        editModifier.modifyMessage(edit.get(), input.message);
+      } catch (UnchangedCommitMessageException ucm) {
+        throw new ResourceConflictException(ucm.getMessage());
+      }
+
       return Response.none();
     }
   }

gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditModifier.java

@@ -227,9 +227,11 @@ public class ChangeEditModifier {
    * @throws AuthException
    * @throws InvalidChangeOperationException
    * @throws IOException
+   * @throws UnchangedCommitMessageException
    */
   public RefUpdate.Result modifyMessage(ChangeEdit edit, String msg)
-      throws AuthException, InvalidChangeOperationException, IOException {
+      throws AuthException, InvalidChangeOperationException, IOException,
+      UnchangedCommitMessageException {
     checkState(!Strings.isNullOrEmpty(msg), "message cannot be null");
     if (!currentUser.get().isIdentifiedUser()) {
       throw new AuthException("Authentication required");
@@ -241,8 +243,7 @@ public class ChangeEditModifier {
     }
 
     if (prevEdit.getFullMessage().equals(msg)) {
-      throw new InvalidChangeOperationException(
-          "New commit message cannot be same as existing commit message");
+      throw new UnchangedCommitMessageException();
     }
 
     IdentifiedUser me = (IdentifiedUser) currentUser.get();

gerrit-server/src/main/java/com/google/gerrit/server/edit/UnchangedCommitMessageException.java

@@ -0,0 +1,23 @@
+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.edit;
+
+public class UnchangedCommitMessageException extends Exception {
+  private static final long serialVersionUID = 1L;
+
+  public UnchangedCommitMessageException() {
+    super("New commit message cannot be same as existing commit message");
+  }
+}