Trim leading and trailing whitespaces in topic name in PutTopic

Whitespaces in the topic name can lead to undesired effects when
querying for the topic. This commit just sanitizes whitespaces of any
kind from the start and end of the topic name.

Change-Id: I0bd032e8f43c3d344af8c31eac449f04b8c5d1d2

Documentation/rest-api-changes.txt

diff --git a/Documentation/rest-api-changes.txt b/Documentation/rest-api-changes.txt
index e64bdb3..fb0a0df 100644
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -889,7 +889,8 @@
 Sets the topic of a change.
 
 The new topic must be provided in the request body inside a
-link:#topic-input[TopicInput] entity.
+link:#topic-input[TopicInput] entity. Any leading or trailing whitespace
+in the topic name will be removed.
 
 .Request
 ----

java/com/google/gerrit/server/restapi/change/PutTopic.java

diff --git a/java/com/google/gerrit/server/restapi/change/PutTopic.java b/java/com/google/gerrit/server/restapi/change/PutTopic.java
index 4685905..45a837a 100644
--- a/java/com/google/gerrit/server/restapi/change/PutTopic.java
+++ b/java/com/google/gerrit/server/restapi/change/PutTopic.java
@@ -75,7 +75,12 @@
           String.format("topic length exceeds the limit (%s)", ChangeUtil.TOPIC_MAX_LENGTH));
     }
 
-    Op op = new Op(input != null ? input : new TopicInput());
+    TopicInput sanitizedInput = input == null ? new TopicInput() : input;
+    if (sanitizedInput.topic != null) {
+      sanitizedInput.topic = sanitizedInput.topic.trim();
+    }
+
+    Op op = new Op(sanitizedInput);
     try (BatchUpdate u =
         updateFactory.create(
             dbProvider.get(), req.getChange().getProject(), req.getUser(), TimeUtil.nowTs())) {

javatests/com/google/gerrit/acceptance/rest/change/TopicIT.java

diff --git a/javatests/com/google/gerrit/acceptance/rest/change/TopicIT.java b/javatests/com/google/gerrit/acceptance/rest/change/TopicIT.java
index 3121812..1d928a2 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/TopicIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/TopicIT.java
@@ -14,6 +14,8 @@
 
 package com.google.gerrit.acceptance.rest.change;
 
+import static com.google.common.truth.Truth.assertThat;
+
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.PushOneCommit.Result;
 import com.google.gerrit.acceptance.RestResponse;
@@ -36,4 +38,24 @@
     response = adminRestSession.put(endpoint, "");
     response.assertNoContent();
   }
+
+  @Test
+  public void leadingAndTrailingWhitespaceGetsSanitized() throws Exception {
+    Result result = createChange();
+    String endpoint = "/changes/" + result.getChangeId() + "/topic";
+    RestResponse response = adminRestSession.put(endpoint, "\t \t topic\t ");
+    response.assertOK();
+
+    assertThat(response.getEntityContent()).isEqualTo(")]}'\n\"topic\"");
+  }
+
+  @Test
+  public void containedWhitespaceDoesNotGetSanitized() throws Exception {
+    Result result = createChange();
+    String endpoint = "/changes/" + result.getChangeId() + "/topic";
+    RestResponse response = adminRestSession.put(endpoint, "t opic");
+    response.assertOK();
+
+    assertThat(response.getEntityContent()).isEqualTo(")]}'\n\"t opic\"");
+  }
 }