branch: add a dry_run parameter to create_branch()

Add a dry_run parameter to create_branch() such that dry_run = 1 will
validate a new branch without trying to create it. This will be used in
`git branch --recurse-submodules` to ensure that the new branch can be
created in all submodules.

Signed-off-by: Glen Choo <chooglen@google.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/branch.h b/branch.h
index cf3a4d3..509cfcc 100644
--- a/branch.h
+++ b/branch.h
@@ -62,11 +62,14 @@ void dwim_and_setup_tracking(struct repository *r, const char *new_ref,
  *   - track causes the new branch to be configured to merge the remote branch
  *     that start_name is a tracking branch for (if any).
  *
+ *   - dry_run causes the branch to be validated but not created.
+ *
  */
 void create_branch(struct repository *r,
 		   const char *name, const char *start_name,
 		   int force, int clobber_head_ok,
-		   int reflog, int quiet, enum branch_track track);
+		   int reflog, int quiet, enum branch_track track,
+		   int dry_run);
 
 /*
  * Check if 'name' can be a valid name for a branch; die otherwise.