ui-log: try to disambiguate ref names

The 'h' querystring parameter in cgit is normally used to specify
a branch (i.e. a ref below refs/heads/), but if a repository contains
a tag with the same name as a branch the output from ui-log would use
the tag as start-revision.

This patch tries to fix the issue by checking if the specified ref is
valid as a branch name; if so, the full refname is used in the call
to setup_revisions().

Noticed-by: Takamori Yamaguchi <akschar@gmail.com>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/ui-log.c b/ui-log.c
index 8dd8b89..d212984 100644
--- a/ui-log.c
+++ b/ui-log.c
@@ -64,18 +64,31 @@ void print_commit(struct commit *commit)
         cgit_free_commitinfo(info);
 }
 
+static const char *disambiguate_ref(const char *ref)
+{
+        unsigned char sha1[20];
+        const char *longref;
+
+        longref = fmt("refs/heads/%s", ref);
+        if (get_sha1(longref, sha1) == 0)
+                return longref;
+
+        return ref;
+}
 
 void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern,
                     char *path, int pager)
 {
         struct rev_info rev;
         struct commit *commit;
-        const char *argv[] = {NULL, tip, NULL, NULL, NULL};
+        const char *argv[] = {NULL, NULL, NULL, NULL, NULL};
         int argc = 2;
         int i, columns = 3;
 
         if (!tip)
-                argv[1] = ctx.qry.head;
+                tip = ctx.qry.head;
+
+        argv[1] = disambiguate_ref(tip);
 
         if (grep && pattern && (!strcmp(grep, "grep") ||
                                 !strcmp(grep, "author") ||