Revert "Expose instanceName in the subject template"

This reverts commit eb4d2d8da7.

Reason for revert:

we observe

com.google.template.soy.tofu.SoyTofuException: In 'print' tag, expression "$instanceAndProjectName" evaluates to undefined.
        at com.google.gerrit.server.mail.template.ChangeSubject(ChangeSubject.soy:9)

in production

Change-Id: I1701b5bcb4720086783536c5c987866bf73e54f4

Documentation/config-mail.txt

@@ -225,10 +225,9 @@ $shortProjectName::
 +
 The project name with the path abbreviated.
 
-$instanceName::
+$instanceAndProjectName::
 +
-The Gerrit instance name, as defined in the
+The Gerrit instance name, followed by the short project name
-link:config-gerrit.html#gerrit.instanceName[configuration].
 
 $addInstanceNameInSubject::
 +

java/com/google/gerrit/server/mail/send/NotificationEmail.java

@@ -111,8 +111,11 @@ public abstract class NotificationEmail extends OutgoingEmail {
     // shortProjectName is the project name with the path abbreviated.
     soyContext.put("shortProjectName", getShortProjectName(projectName));
 
+    // instanceAndProjectName is the instance's name followed by the abbreviated project path
+    soyContext.put(
+        "instanceAndProjectName",
+        getInstanceAndProjectName(args.instanceNameProvider.get(), projectName));
     soyContext.put("addInstanceNameInSubject", args.addInstanceNameInSubject);
-    soyContext.put("instanceName", args.instanceNameProvider.get());
 
     soyContextEmailData.put("sshHost", getSshHost());
 
@@ -133,4 +136,14 @@ public abstract class NotificationEmail extends OutgoingEmail {
 
     return "..." + projectName.substring(lastIndexSlash + 1);
   }
+
+  @VisibleForTesting
+  protected static String getInstanceAndProjectName(String instanceName, String projectName) {
+    if (instanceName == null || instanceName.isEmpty()) {
+      return getShortProjectName(projectName);
+    }
+    // Extract the project name (everything after the last slash) and prepends it with gerrit's
+    // instance name
+    return instanceName + "/" + projectName.substring(projectName.lastIndexOf('/') + 1);
+  }
 }

javatests/com/google/gerrit/server/mail/send/NotificationEmailTest.java

@@ -19,6 +19,19 @@ import static com.google.common.truth.Truth.assertThat;
 import org.junit.Test;
 
 public class NotificationEmailTest {
+
+  @Test
+  public void getInstanceAndProjectName_returnsTheRightValue() {
+    String instanceAndProjectName = NotificationEmail.getInstanceAndProjectName("test", "/my/api");
+    assertThat(instanceAndProjectName).isEqualTo("test/api");
+  }
+
+  @Test
+  public void getInstanceAndProjectName_handlesNull() {
+    String instanceAndProjectName = NotificationEmail.getInstanceAndProjectName(null, "/my/api");
+    assertThat(instanceAndProjectName).isEqualTo("...api");
+  }
+
   @Test
   public void getShortProjectName() {
     assertThat(NotificationEmail.getShortProjectName("/api")).isEqualTo("api");

resources/com/google/gerrit/server/mail/ChangeSubject.soy

@@ -22,13 +22,13 @@
  * @param branch
  * @param change
  * @param shortProjectName
- * @param instanceName
+ * @param instanceAndProjectName
  * @param addInstanceNameInSubject boolean
  */
 {template .ChangeSubject kind="text"}
   {if not $addInstanceNameInSubject}
     Change in {$shortProjectName}[{$branch.shortName}]: {$change.shortSubject}
   {else}
-    [{$instanceName}] Change in {$shortProjectName}[{$branch.shortName}]: {$change.shortSubject}
+    Change in {$instanceAndProjectName}[{$branch.shortName}]: {$change.shortSubject}
   {/if}
 {/template}