superproject: support a new revision attribute.

Tested:
$ ./run_tests

Verified that a manifest that specified superproject revision would use
the specified revision, and superproject will use the default revision.

Note that this is a slight behavior change from earlier repo versions,
which would always use the branch name of the manifest itself. However,
the new behavior would be more consisitent with regular "project"
element and would allow superproject be used even if it is not enabled
for the particular manifest branch, so we have decided to make the
change as it would provide more flexibility and better matches what
other elements would do.

Bug: [google internal] b/187868160
Change-Id: I35255ee347aff6e65179f7879d52931f168b477e
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/317643
Tested-by: Xin Li <delphij@google.com>
Reviewed-by: Raman Tenneti <rtenneti@google.com>
Reviewed-by: Mike Frysinger <vapier@google.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/docs/manifest-format.md b/docs/manifest-format.md
index 854e5e1b..ed297ae7 100644
--- a/docs/manifest-format.md
+++ b/docs/manifest-format.md
@@ -103,8 +103,9 @@ following DTD:
   <!ATTLIST repo-hooks enabled-list CDATA #REQUIRED>
 
   <!ELEMENT superproject EMPTY>
-  <!ATTLIST superproject name    CDATA #REQUIRED>
-  <!ATTLIST superproject remote  IDREF #IMPLIED>
+  <!ATTLIST superproject name     CDATA #REQUIRED>
+  <!ATTLIST superproject remote   IDREF #IMPLIED>
+  <!ATTLIST superproject revision CDATA #IMPLIED>
 
   <!ELEMENT contactinfo EMPTY>
   <!ATTLIST contactinfo bugurl  CDATA #REQUIRED>
@@ -432,6 +433,11 @@ same meaning as project's name attribute. See the
 Attribute `remote`: Name of a previously defined remote element.
 If not supplied the remote given by the default element is used.
 
+Attribute `revision`: Name of the Git branch the manifest wants
+to track for this superproject. If not supplied the revision given
+by the remote element is used if applicable, else the default
+element is used.
+
 ### Element contactinfo
 
 ***