ui-summary: Use default branch for readme if : prefix

If the readme value begins with ":", and has no specified branch before
it, use the repository's default branch.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

2 files changed, 9 insertions, 2 deletions

diff --git a/cgitrc.5.txt b/cgitrc.5.txt
index 9b803b3..8a0a9c9 100644
--- a/cgitrc.5.txt
+++ b/cgitrc.5.txt
@@ -505,7 +505,9 @@ repo.readme::
         A path (relative to <repo.path>) which specifies a file to include
         verbatim as the "About" page for this repo. You may also specify a
         git refspec by head or by hash by prepending the refspec followed by
-        a colon. For example, "master:docs/readme.mkd" Default value: <readme>.
+        a colon. For example, "master:docs/readme.mkd". If the value begins
+        with a colon, i.e. ":docs/readme.rst", the default branch of the
+        repository will be used. Default value: <readme>.
 
 repo.snapshots::
         A mask of allowed snapshot-formats for this repo, restricted by the
diff --git a/ui-summary.c b/ui-summary.c
index f965b32..abf914e 100644
--- a/ui-summary.c
+++ b/ui-summary.c
@@ -108,7 +108,12 @@ void cgit_print_repo_readme(char *path)
         colon = strchr(ctx.repo->readme, ':');
         if (colon && strlen(colon) > 1) {
                 *colon = '\0';
-                ref = ctx.repo->readme;
+                /* If it starts with a colon, we want to use
+                 * the default branch */
+                if (colon == ctx.repo->readme && ctx.repo->defbranch)
+                        ref = ctx.repo->defbranch;
+                else
+                        ref = ctx.repo->readme;
                 ctx.repo->readme = colon + 1;
                 if (!(*ctx.repo->readme))
                         return;