CreateBranch: Allow revision in input to be empty

If a revision in the input is not specified we default to the HEAD
revision, but when the revision in the input was empty we failed with
400 Bad Request. Be more tolerant and consistent and default to the HEAD
revision too if the specified revision is empty.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: Ibc1461b744b65dba4857b3ffa00b49bd2c96df99

2 files changed, 28 insertions, 1 deletions

diff --git a/java/com/google/gerrit/server/restapi/project/CreateBranch.java b/java/com/google/gerrit/server/restapi/project/CreateBranch.java
index 62106e8c1d..05525b5e28 100644
--- a/java/com/google/gerrit/server/restapi/project/CreateBranch.java
+++ b/java/com/google/gerrit/server/restapi/project/CreateBranch.java
@@ -16,6 +16,7 @@ package com.google.gerrit.server.restapi.project;
 
 import static com.google.gerrit.reviewdb.client.RefNames.isConfigRef;
 
+import com.google.common.base.Strings;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.extensions.api.projects.BranchInfo;
 import com.google.gerrit.extensions.api.projects.BranchInput;
@@ -91,7 +92,7 @@ public class CreateBranch
     if (input.ref != null && !ref.equals(input.ref)) {
       throw new BadRequestException("ref must match URL");
     }
-    if (input.revision == null) {
+    if (Strings.isNullOrEmpty(input.revision)) {
       input.revision = Constants.HEAD;
     }
     while (ref.startsWith("/")) {
diff --git a/javatests/com/google/gerrit/acceptance/rest/project/CreateBranchIT.java b/javatests/com/google/gerrit/acceptance/rest/project/CreateBranchIT.java
index a4a87d5464..cd442e5458 100644
--- a/javatests/com/google/gerrit/acceptance/rest/project/CreateBranchIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/project/CreateBranchIT.java
@@ -147,6 +147,32 @@ public class CreateBranchIT extends AbstractDaemonTest {
   }
 
   @Test
+  public void createWithoutSpecifyingRevision() throws Exception {
+    // If revision is not specified, the branch is created based on HEAD, which points to master.
+    RevCommit expectedRevision = getRemoteHead(project, "master");
+
+    BranchInput input = new BranchInput();
+    input.revision = null;
+    BranchInfo created = branch(testBranch).create(input).get();
+    assertThat(created.ref).isEqualTo(testBranch.get());
+    assertThat(created.revision).isEqualTo(expectedRevision.name());
+    assertThat(getRemoteHead(project, testBranch.getShortName())).isEqualTo(expectedRevision);
+  }
+
+  @Test
+  public void createWithEmptyRevision() throws Exception {
+    // If revision is not specified, the branch is created based on HEAD, which points to master.
+    RevCommit expectedRevision = getRemoteHead(project, "master");
+
+    BranchInput input = new BranchInput();
+    input.revision = "";
+    BranchInfo created = branch(testBranch).create(input).get();
+    assertThat(created.ref).isEqualTo(testBranch.get());
+    assertThat(created.revision).isEqualTo(expectedRevision.name());
+    assertThat(getRemoteHead(project, testBranch.getShortName())).isEqualTo(expectedRevision);
+  }
+
+  @Test
   public void createWithBranchNameAsRevision() throws Exception {
     RevCommit expectedRevision = getRemoteHead(project, "master");