Adapt tutorial to cygwin and add test case

diff --git a/read-tree.c b/read-tree.c
index 9ace5bb0ab65cd2c0abb98e333972429e4de0dd0..5fdf58d240e68f2c4b332dbdd02be357641127f8 100644 (file)
--- a/read-tree.c
+++ b/read-tree.c
@@ -12,6 +12,9 @@
 
 static int merge = 0;
 static int update = 0;
+static int index_only = 0;
+static int nontrivial_merge = 0;
+static int trivial_merges_only = 0;
 
 static int head_idx = -1;
 static int merge_size = 0;
@@ -274,6 +277,9 @@ static int unpack_trees(merge_fn_t fn)
        if (unpack_trees_rec(posns, len, "", fn, &indpos))
                return -1;
 
+       if (trivial_merges_only && nontrivial_merge)
+               die("Merge requires file-level merging");
+
        check_updates(active_cache, active_nr);
        return 0;
 }
@@ -306,6 +312,9 @@ static void verify_uptodate(struct cache_entry *ce)
 {
        struct stat st;
 
+       if (index_only)
+               return;
+
        if (!lstat(ce->name, &st)) {
                unsigned changed = ce_match_stat(ce, &st);
                if (!changed)
@@ -358,12 +367,15 @@ static int keep_entry(struct cache_entry *ce)
 static void show_stage_entry(FILE *o,
                             const char *label, const struct cache_entry *ce)
 {
-       fprintf(stderr, "%s%06o %s %d\t%s\n",
-               label,
-               ntohl(ce->ce_mode),
-               sha1_to_hex(ce->sha1),
-               ce_stage(ce),
-               ce->name);
+       if (!ce)
+               fprintf(o, "%s (missing)\n", label);
+       else
+               fprintf(o, "%s%06o %s %d\t%s\n",
+                       label,
+                       ntohl(ce->ce_mode),
+                       sha1_to_hex(ce->sha1),
+                       ce_stage(ce),
+                       ce->name);
 }
 #endif
 
@@ -453,6 +465,8 @@ static int threeway_merge(struct cache_entry **stages)
                verify_uptodate(index);
        }
 
+       nontrivial_merge = 1;
+
        /* #2, #3, #4, #6, #7, #9, #11. */
        count = 0;
        if (!head_match || !remote_match) {
@@ -576,7 +590,7 @@ static int read_cache_unmerged(void)
        return deleted;
 }
 
-static const char read_tree_usage[] = "git-read-tree (<sha> | -m [-u] <sha1> [<sha2> [<sha3>]])";
+static const char read_tree_usage[] = "git-read-tree (<sha> | -m [-u | -i] <sha1> [<sha2> [<sha3>]])";
 
 static struct cache_file cache_file;
 
@@ -595,12 +609,22 @@ int main(int argc, char **argv)
        for (i = 1; i < argc; i++) {
                const char *arg = argv[i];
 
-               /* "-u" means "update", meaning that a merge will update the working directory */
+               /* "-u" means "update", meaning that a merge will update
+                * the working tree.
+                */
                if (!strcmp(arg, "-u")) {
                        update = 1;
                        continue;
                }
 
+               /* "-i" means "index only", meaning that a merge will
+                * not even look at the working tree.
+                */
+               if (!strcmp(arg, "-i")) {
+                       index_only = 1;
+                       continue;
+               }
+
                /* This differs from "-m" in that we'll silently ignore unmerged entries */
                if (!strcmp(arg, "--reset")) {
                        if (stage || merge)
@@ -612,9 +636,9 @@ int main(int argc, char **argv)
                        continue;
                }
 
-               if (!strcmp(arg, "--head")) {
-                       head_idx = stage - 1;
-                       fn = threeway_merge;
+               if (!strcmp(arg, "--trivial")) {
+                       trivial_merges_only = 1;
+                       continue;
                }
 
                /* "-m" stands for "merge", meaning we start in stage 1 */
@@ -628,15 +652,20 @@ int main(int argc, char **argv)
                        continue;
                }
 
+               /* using -u and -i at the same time makes no sense */
+               if (1 < index_only + update)
+                       usage(read_tree_usage);
+
                if (get_sha1(arg, sha1) < 0)
                        usage(read_tree_usage);
                if (list_tree(sha1) < 0)
                        die("failed to unpack tree object %s", arg);
                stage++;
        }
-       if (update && !merge)
+       if ((update||index_only) && !merge)
                usage(read_tree_usage);
-       if (merge && !fn) {
+
+       if (merge) {
                if (stage < 2)
                        die("just how do you expect me to merge %d trees?", stage-1);
                switch (stage - 1) {
@@ -653,9 +682,7 @@ int main(int argc, char **argv)
                        fn = threeway_merge;
                        break;
                }
-       }
 
-       if (head_idx < 0) {
                if (stage - 1 >= 3)
                        head_idx = stage - 2;
                else