Allow the default low-level merge driver to be configured.

When no 'merge' attribute is given to a path, merge-recursive
uses the built-in xdl-merge as the low-level merge driver.

A new configuration item 'merge.default' can name a low-level
merge driver of user's choice to be used instead.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/merge-recursive.c b/merge-recursive.c
index 8ec18ad5779c5c1de254411167533eb6ac55089f..5983000971dbe5f71156f941beceb1a9911bf864 100644 (file)
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -839,12 +839,18 @@ static struct user_merge_fn {
        char *cmdline;
        char b_[1];
 } *ll_user_merge_fns, **ll_user_merge_fns_tail;
+static const char *default_ll_merge;
 
 static int read_merge_config(const char *var, const char *value)
 {
        struct user_merge_fn *fn;
        int blen, nlen;
 
+       if (!strcmp(var, "merge.default")) {
+               default_ll_merge = strdup(value);
+               return 0;
+       }
+
        if (strcmp(var, "merge.driver"))
                return 0;
        if (!value)
@@ -900,8 +906,12 @@ static ll_merge_fn find_ll_merge_fn(void *merge_attr, const char **cmdline)
                return ll_xdl_merge;
        else if (ATTR_FALSE(merge_attr))
                return ll_binary_merge;
-       else if (ATTR_UNSET(merge_attr))
-               return ll_xdl_merge;
+       else if (ATTR_UNSET(merge_attr)) {
+               if (!default_ll_merge)
+                       return ll_xdl_merge;
+               else
+                       name = default_ll_merge;
+       }
        else
                name = merge_attr;