Revert "Fix: Permission.PUSH_MERGE checking for push bypassing Gerrit"

This reverts commit f6159bed86.

Broke direct push of merges for all projects that followed
documentation and included a 'Push Merge Commit' ACL prefixed with
"refs/for/".

The fix for the 'Push Merge Commit' handling looks good, but it should
be accompanied by a migration that adjusts existing configuration.

Change-Id: Id2a25551d8e9953cd1e678086d491133f5f2d987

Documentation/access-control.txt

@@ -609,11 +609,12 @@ push to happen.  Some projects wish to restrict merges to being created
 by Gerrit. By granting `Push` without `Push Merge Commit`, the only
 merges that enter the system will be those created by Gerrit.
 
-For pushing a merge commit for review, the reference name connected to
-a `Push Merge Commit` entry must be prefixed with `refs/for/`,
-for example `refs/for/refs/heads/BRANCH`. For pushing a merge commit
-directly into the repository bypassing review, the reference name
-must be `refs/heads/BRANCH`.
+The reference name connected to a `Push Merge Commit` entry must always
+be prefixed with `refs/for/`, for example `refs/for/refs/heads/BRANCH`.
+This applies even for an entry that complements a `Push` entry for
+`refs/heads/BRANCH` that allows direct pushes of non-merge commits, and
+the intention of the `Push Merge Commit` entry is to allow direct pushes
+of merge commits.
 
 
 [[category_push_annotated]]

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

@@ -2002,8 +2002,7 @@ public class ReceiveCommits {
     if (ctl.canForgeAuthor()
         && ctl.canForgeCommitter()
         && ctl.canForgeGerritServerIdentity()
-        && (MagicBranch.isForReview(cmd.getRefName()) ? ctl.canUploadMerges()
-            : ctl.canPushMerges())
+        && ctl.canUploadMerges()
         && !projectControl.getProjectState().isUseSignedOffBy()
         && Iterables.isEmpty(rejectCommits)
         && !GitRepositoryManager.REF_CONFIG.equals(ctl.getRefName())

gerrit-server/src/main/java/com/google/gerrit/server/git/validators/CommitValidators.java

@@ -354,21 +354,11 @@ public class CommitValidators {
     @Override
     public List<CommitValidationMessage> onCommitReceived(
         CommitReceivedEvent receiveEvent) throws CommitValidationException {
-      if (receiveEvent.commit.getParentCount() > 1) {
-        if (MagicBranch.isForReview(receiveEvent.command.getRefName())) {
-          if (!refControl.canUploadMerges()) {
-            throw new CommitValidationException(
-                "you are not allowed to upload merges for review");
-          }
-        } else {
-          if (!refControl.canPushMerges()) {
-            throw new CommitValidationException(
-                "you are not allowed to push merges directly bypassing code review");
-          }
-        }
+      if (receiveEvent.commit.getParentCount() > 1
+          && !refControl.canUploadMerges()) {
+        throw new CommitValidationException("you are not allowed to upload merges");
       }
-
-      return Collections.<CommitValidationMessage> emptyList();
+      return Collections.<CommitValidationMessage>emptyList();
     }
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/project/RefControl.java

@@ -147,17 +147,7 @@ public class RefControl {
         && canWrite();
   }
 
-  /**
-   * @return true if this user can push merge commits directly bypassing code
-   *         review to this ref.
-   */
-  public boolean canPushMerges() {
-    return projectControl.controlForRef(getRefName()).canPerform(
-        Permission.PUSH_MERGE)
-        && canWrite();
-  }
-
-  /** @return true if this user can upload merge commits to this ref for review */
+  /** @return true if this user can submit merge patch sets to this ref */
   public boolean canUploadMerges() {
     return projectControl.controlForRef("refs/for/" + getRefName())
         .canPerform(Permission.PUSH_MERGE)

gerrit-server/src/main/java/com/google/gerrit/server/util/MagicBranch.java

@@ -51,11 +51,6 @@ public final class MagicBranch {
         || refName.startsWith(NEW_CHANGE);
   }
 
-  /** Checks if the supplied ref name is a magic branch for review */
-  public static boolean isForReview(String refName) {
-    return isMagicBranch(refName);
-  }
-
   /** Returns the ref name prefix for a magic branch, <code>null</code> if the branch is not magic */
   public static String getMagicRefNamePrefix(String refName) {
     if (refName.startsWith(NEW_DRAFT_CHANGE)) {