Support mandatory capabilities

Add support for marking capability as mandatory for hosting git version
to understand. This is useful for helpers which require various types
of assistance from main git binary.

Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-remote-helpers.txt b/Documentation/git-remote-helpers.txt
index 5cfdc0cfc553dc01f6f1c7cb185e79449ee0b0a8..20a05fe9d890e921779fa32da15edac6bc688687 100644 (file)
--- a/Documentation/git-remote-helpers.txt
+++ b/Documentation/git-remote-helpers.txt
@@ -25,7 +25,10 @@ Commands are given by the caller on the helper's standard input, one per line.
 
 'capabilities'::
        Lists the capabilities of the helper, one per line, ending
-       with a blank line.
+       with a blank line. Each capability may be preceeded with '*'.
+       This marks them mandatory for git version using the remote
+       helper to understand (unknown mandatory capability is fatal
+       error).
 
 'list'::
        Lists the refs, one per line, in the format "<value> <name>

diff --git a/transport-helper.c b/transport-helper.c
index a721dc25beb31350f6fc64f7446b340f83c707c8..4b17aaa237d498dcaaac14df1730af5b67b47705 100644 (file)
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -93,25 +93,38 @@ static struct child_process *get_helper(struct transport *transport)
 
        data->out = xfdopen(helper->out, "r");
        while (1) {
+               const char *capname;
+               int mandatory = 0;
                recvline(data, &buf);
 
                if (!*buf.buf)
                        break;
+
+               if (*buf.buf == '*') {
+                       capname = buf.buf + 1;
+                       mandatory = 1;
+               } else
+                       capname = buf.buf;
+
                if (debug)
-                       fprintf(stderr, "Debug: Got cap %s\n", buf.buf);
-               if (!strcmp(buf.buf, "fetch"))
+                       fprintf(stderr, "Debug: Got cap %s\n", capname);
+               if (!strcmp(capname, "fetch"))
                        data->fetch = 1;
-               if (!strcmp(buf.buf, "option"))
+               else if (!strcmp(capname, "option"))
                        data->option = 1;
-               if (!strcmp(buf.buf, "push"))
+               else if (!strcmp(capname, "push"))
                        data->push = 1;
-               if (!strcmp(buf.buf, "import"))
+               else if (!strcmp(capname, "import"))
                        data->import = 1;
-               if (!data->refspecs && !prefixcmp(buf.buf, "refspec ")) {
+               else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
                        ALLOC_GROW(refspecs,
                                   refspec_nr + 1,
                                   refspec_alloc);
                        refspecs[refspec_nr++] = strdup(buf.buf + strlen("refspec "));
+               } else if (mandatory) {
+                       die("Unknown madatory capability %s. This remote "
+                           "helper probably needs newer version of Git.\n",
+                           capname);
                }
        }
        if (refspecs) {