ChangeBundle: Handle leading/trailing whitespace in topic/desc

PatchSet descriptions should use the same logic as Change topics to
ignore whitespace that JGit won't accurately parse out of a NoteDb
footer. While writing this, I found that topics should actually be
trimming leading as well as trailing whitespace. Use a single
trimming implementation for both of these.

Change-Id: I564fe674d9b5970717cb3e923b0aa28522c6347a

gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeBundle.java

diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeBundle.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeBundle.java
index e140f2d..1fe0e64 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeBundle.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeBundle.java
@@ -438,7 +438,7 @@
       excludeCurrentPatchSetId = !bundleA.validPatchSetPredicate().apply(a.currentPatchSetId());
       excludeSubject = bSubj.startsWith(aSubj) || excludeCurrentPatchSetId;
       excludeOrigSubj = true;
-      String aTopic = trimLeadingOrNull(a.getTopic());
+      String aTopic = trimOrNull(a.getTopic());
       excludeTopic =
           Objects.equals(aTopic, b.getTopic()) || "".equals(aTopic) && b.getTopic() == null;
       aUpdated = bundleA.getLatestTimestamp();
@@ -450,7 +450,7 @@
       excludeCurrentPatchSetId = !bundleB.validPatchSetPredicate().apply(b.currentPatchSetId());
       excludeSubject = aSubj.startsWith(bSubj) || excludeCurrentPatchSetId;
       excludeOrigSubj = true;
-      String bTopic = trimLeadingOrNull(b.getTopic());
+      String bTopic = trimOrNull(b.getTopic());
       excludeTopic =
           Objects.equals(bTopic, a.getTopic()) || a.getTopic() == null && "".equals(bTopic);
       bUpdated = bundleB.getLatestTimestamp();
@@ -486,8 +486,8 @@
     }
   }
 
-  private static String trimLeadingOrNull(String s) {
-    return s != null ? CharMatcher.whitespace().trimLeadingFrom(s) : null;
+  private static String trimOrNull(String s) {
+    return s != null ? CharMatcher.whitespace().trimFrom(s) : null;
   }
 
   private static String cleanReviewDbSubject(String s) {
@@ -653,7 +653,20 @@
       PatchSet b = bs.get(id);
       String desc = describe(id);
       String pushCertField = "pushCertificate";
-      diffColumnsExcluding(diffs, PatchSet.class, desc, bundleA, a, bundleB, b, pushCertField);
+
+      boolean excludeDesc = false;
+      if (bundleA.source == REVIEW_DB && bundleB.source == NOTE_DB) {
+        excludeDesc = Objects.equals(trimOrNull(a.getDescription()), b.getDescription());
+      } else if (bundleA.source == NOTE_DB && bundleB.source == REVIEW_DB) {
+        excludeDesc = Objects.equals(a.getDescription(), trimOrNull(b.getDescription()));
+      }
+
+      List<String> exclude = Lists.newArrayList(pushCertField);
+      if (excludeDesc) {
+        exclude.add("description");
+      }
+
+      diffColumnsExcluding(diffs, PatchSet.class, desc, bundleA, a, bundleB, b, exclude);
       diffValues(diffs, desc, trimPushCert(a), trimPushCert(b), pushCertField);
     }
   }

gerrit-server/src/test/java/com/google/gerrit/server/notedb/ChangeBundleTest.java

diff --git a/gerrit-server/src/test/java/com/google/gerrit/server/notedb/ChangeBundleTest.java b/gerrit-server/src/test/java/com/google/gerrit/server/notedb/ChangeBundleTest.java
index f095347..151a053 100644
--- a/gerrit-server/src/test/java/com/google/gerrit/server/notedb/ChangeBundleTest.java
+++ b/gerrit-server/src/test/java/com/google/gerrit/server/notedb/ChangeBundleTest.java
@@ -355,9 +355,9 @@
   }
 
   @Test
-  public void diffChangesIgnoresLeadingWhitespaceInReviewDbTopics() throws Exception {
+  public void diffChangesIgnoresLeadingAndTrailingWhitespaceInReviewDbTopics() throws Exception {
     Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    c1.setTopic(" abc");
+    c1.setTopic(" abc ");
     Change c2 = clone(c1);
     c2.setTopic("abc");
 
@@ -368,7 +368,7 @@
     ChangeBundle b2 =
         new ChangeBundle(
             c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ":" + " { abc} != {abc}");
+    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ":" + " { abc } != {abc}");
 
     // Leading whitespace in ReviewDb topic is ignored.
     b1 =
@@ -380,7 +380,7 @@
     assertNoDiffs(b1, b2);
     assertNoDiffs(b2, b1);
 
-    // Must match except for the leading whitespace.
+    // Must match except for the leading/trailing whitespace.
     Change c3 = clone(c1);
     c3.setTopic("cba");
     b1 =
@@ -389,7 +389,7 @@
     b2 =
         new ChangeBundle(
             c3, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ":" + " { abc} != {cba}");
+    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ":" + " { abc } != {cba}");
   }
 
   @Test
@@ -1245,6 +1245,52 @@
   }
 
   @Test
+  public void diffPatchSetsIgnoresLeadingAndTrailingWhitespaceInReviewDbDescriptions()
+      throws Exception {
+    Change c = TestChanges.newChange(project, accountId);
+
+    PatchSet ps1 = new PatchSet(new PatchSet.Id(c.getId(), 1));
+    ps1.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
+    ps1.setUploader(accountId);
+    ps1.setCreatedOn(TimeUtil.nowTs());
+    ps1.setDescription(" abc ");
+    PatchSet ps2 = clone(ps1);
+    ps2.setDescription("abc");
+
+    // Both ReviewDb, exact match required.
+    ChangeBundle b1 =
+        new ChangeBundle(
+            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), REVIEW_DB);
+    ChangeBundle b2 =
+        new ChangeBundle(
+            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), REVIEW_DB);
+    assertDiffs(
+        b1, b2, "description differs for PatchSet.Id " + ps1.getId() + ":" + " { abc } != {abc}");
+
+    // Whitespace in ReviewDb description is ignored.
+    b1 =
+        new ChangeBundle(
+            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), REVIEW_DB);
+    b2 =
+        new ChangeBundle(
+            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), NOTE_DB);
+    assertNoDiffs(b1, b2);
+    assertNoDiffs(b2, b1);
+
+    // Must match except for the leading/trailing whitespace.
+    PatchSet ps3 = clone(ps1);
+    ps3.setDescription("cba");
+    b1 =
+        new ChangeBundle(
+            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), REVIEW_DB);
+    b2 =
+        new ChangeBundle(
+            c, messages(), patchSets(ps3), approvals(), comments(), reviewers(), NOTE_DB);
+    assertDiffs(
+        b1, b2, "description differs for PatchSet.Id " + ps1.getId() + ":" + " { abc } != {cba}");
+  }
+
+  @Test
   public void diffPatchSetApprovalKeySets() throws Exception {
     Change c = TestChanges.newChange(project, accountId);
     int id = c.getId().get();