Merge branch 'stable-2.8'

* stable-2.8:
  Update 2.8.2 release notes
  Bump version to 2.8.2 in plugin API and archetypes
  Prevent duplicate commits in same project when uploading to refs/changes/n
  Bump GERRIT_VERSION to 2.8.2
  Update 2.8.2 release notes
  PostReview: update and insert comments/approvals in a single step

Conflicts:
	VERSION
	gerrit-plugin-archetype/pom.xml
	gerrit-plugin-gwt-archetype/pom.xml
	gerrit-plugin-gwtui/pom.xml
	gerrit-plugin-js-archetype/pom.xml
	gerrit-server/src/main/java/com/google/gerrit/server/change/PostReview.java
	gerrit-server/src/main/java/com/google/gerrit/server/git/ReceiveCommits.java

Change-Id: I7a611d4f9c16b8d5f3abdcd8228fca0b636d792c

Documentation/error-commit-already-exists.txt

@@ -1,9 +1,18 @@
 = commit already exists
 
-With this error message Gerrit rejects to push a commit to an
+With "commit already exists (as current patchset)" or
-existing change via `refs/changes/n` if the commit was already
+"commit already exists (in the change)" error message
-successfully pushed to the change.  In this case there is no
+Gerrit rejects to push a commit to an existing change via
-new commit and consequently there is nothing for Gerrit to do.
+`refs/changes/n` if the commit was already successfully
+pushed to the change.
+
+With "commit already exists (in the project)" error message
+Gerrit rejects to push a commit to an existing change via
+`refs/changes/n` if the commit was already successfully
+pushed to a change in project scope.
+
+In any above case there is no new commit and consequently
+there is nothing for Gerrit to do.
 
 For further information about how to resolve this error, please
 refer to link:error-no-new-changes.html[no new changes].

Documentation/error-no-new-changes.txt

@@ -1,8 +1,9 @@
 = no new changes
 
 With this error message Gerrit rejects to push a commit if the pushed
-commit was already successfully pushed to Gerrit. In this case there
+commit was already successfully pushed to Gerrit in project scope.
-is no new change and consequently there is nothing for Gerrit to do.
+In this case there is no new change and consequently there is nothing
+for Gerrit to do.
 
 If your push is failing with this error message, you normally
 don't have to do anything since the commit was already successfully
@@ -30,7 +31,7 @@ means:
 . you cannot reset a change to an old patch set by pushing the old
   commit for this change again
 . if a commit was pushed to one branch you cannot push this commit
-  to another branch
+  to another branch in project scope.
 . if a commit was pushed directly to a branch (without going through
   code review) you cannot push this commit once again for code
   review (please note that in this case searching by the commit ID
@@ -38,11 +39,11 @@ means:
 
 If you need to re-push a commit you may rewrite this commit by
 link:http://www.kernel.org/pub/software/scm/git/docs/git-commit.html[amending] it or doing an interactive link:http://www.kernel.org/pub/software/scm/git/docs/git-rebase.html[git rebase]. By rewriting the
-commit you actually create a new commit (with a new commit ID) which
+commit you actually create a new commit (with a new commit ID in
-can then be pushed to Gerrit. If the old commit contains a Change-Id
+project scope) which can then be pushed to Gerrit. If the old commit
-in the commit message you also need to replace it with a new
+contains a Change-Id in the commit message you also need to replace
-Change-Id (case 1. and 3. above), otherwise the push will fail with
+it with a new Change-Id (case 1. and 3. above), otherwise the push
-another error message.
+will fail with another error message.
 
 
 GERRIT

ReleaseNotes/ReleaseNotes-2.8.2.txt

@@ -124,6 +124,19 @@ Handle null commits when updating submodules.
 In some edge cases it was possible that a null commit would exist, and this
 caused a crash when updating submodules.
 
+* Update and insert comments/approvals in a single step.
++
+When a review includes both new label scores and updates to existing label
+scores, use `upsert` to record them all at the same time, rather than in
+separate `update` and `insert` operations.
+
+* link:https://code.google.com/p/gerrit/issues/detail?id=2374[Issue 2374]:
+Prevent duplicate commits in same project when uploading to `refs/changes/n`.
++
+Under certain circumstances, when pushing to `refs/changes/n`, the same
+commit could be pushed onto multiple changes even if the changes were on the
+same branch.
+
 * Remove dependency on joda time library in gerrit launcher.
 +
 The joda time library was being unnecessarily packaged in the root of

gerrit-server/src/main/java/com/google/gerrit/server/git/ReceiveCommits.java

@@ -1780,7 +1780,7 @@ public class ReceiveCommits {
       if (newCommit == priorCommit) {
         // Ignore requests to make the change its current state.
         skip = true;
-        reject(inputCommand, "commit already exists");
+        reject(inputCommand, "commit already exists (as current patchset)");
         return false;
       }
 
@@ -1792,10 +1792,18 @@ public class ReceiveCommits {
         reject(inputCommand, "change " + ontoChange + " closed");
         return false;
       } else if (revisions.containsKey(newCommit)) {
-        reject(inputCommand, "commit already exists");
+        reject(inputCommand, "commit already exists (in the change)");
         return false;
       }
 
+      for (final Ref r : rp.getRepository().getRefDatabase()
+          .getRefs("refs/changes").values()) {
+        if (r.getObjectId().equals(inputCommand.getNewId())) {
+          reject(inputCommand, "commit already exists (in the project)");
+          return false;
+        }
+      }
+
       for (RevCommit prior : revisions.keySet()) {
         // Don't allow a change to directly depend upon itself. This is a
         // very common error due to users making a new commit rather than