Try normalizing files to avoid delete/modify conflicts when merging
[gitweb.git] / merge-recursive.c
index 1870448d98d56fea31af56953dc33f6529d1d380..5ad8fc9e7ea7c6653e28343ccc0fa0c260e3affd 100644 (file)
 #include "merge-recursive.h"
 #include "dir.h"
 
-static struct tree *shift_tree_object(struct tree *one, struct tree *two)
+static struct tree *shift_tree_object(struct tree *one, struct tree *two,
+                                     const char *subtree_shift)
 {
        unsigned char shifted[20];
 
-       /*
-        * NEEDSWORK: this limits the recursion depth to hardcoded
-        * value '2' to avoid excessive overhead.
-        */
-       shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
+       if (!*subtree_shift) {
+               shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
+       } else {
+               shift_tree_by(one->object.sha1, two->object.sha1, shifted,
+                             subtree_shift);
+       }
        if (!hashcmp(two->object.sha1, shifted))
                return two;
        return lookup_tree(shifted);
@@ -87,6 +89,7 @@ static void flush_output(struct merge_options *o)
        }
 }
 
+__attribute__((format (printf, 3, 4)))
 static void output(struct merge_options *o, int v, const char *fmt, ...)
 {
        int len;
@@ -171,23 +174,6 @@ static int git_merge_trees(int index_only,
        int rc;
        struct tree_desc t[3];
        struct unpack_trees_options opts;
-       struct unpack_trees_error_msgs msgs = {
-               /* would_overwrite */
-               "Your local changes to '%s' would be overwritten by merge.  Aborting.",
-               /* not_uptodate_file */
-               "Your local changes to '%s' would be overwritten by merge.  Aborting.",
-               /* not_uptodate_dir */
-               "Updating '%s' would lose untracked files in it.  Aborting.",
-               /* would_lose_untracked */
-               "Untracked working tree file '%s' would be %s by merge.  Aborting",
-               /* bind_overlap -- will not happen here */
-               NULL,
-       };
-       if (advice_commit_before_merge) {
-               msgs.would_overwrite = msgs.not_uptodate_file =
-                       "Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
-                       "Please, commit your changes or stash them before you can merge.";
-       }
 
        memset(&opts, 0, sizeof(opts));
        if (index_only)
@@ -199,7 +185,7 @@ static int git_merge_trees(int index_only,
        opts.fn = threeway_merge;
        opts.src_index = &the_index;
        opts.dst_index = &the_index;
-       opts.msgs = msgs;
+       opts.msgs = get_porcelain_error_msgs();
 
        init_tree_desc_from_tree(t+0, common);
        init_tree_desc_from_tree(t+1, head);
@@ -216,13 +202,14 @@ struct tree *write_tree_from_memory(struct merge_options *o)
 
        if (unmerged_cache()) {
                int i;
-               output(o, 0, "There are unmerged index entries:");
+               fprintf(stderr, "BUG: There are unmerged index entries:\n");
                for (i = 0; i < active_nr; i++) {
                        struct cache_entry *ce = active_cache[i];
                        if (ce_stage(ce))
-                               output(o, 0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
+                               fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
+                                       (int)ce_namelen(ce), ce->name);
                }
-               return NULL;
+               die("Bug in merge-recursive.c");
        }
 
        if (!active_cache_tree)
@@ -422,7 +409,7 @@ static int remove_file(struct merge_options *o, int clean,
                        return -1;
        }
        if (update_working_directory) {
-               if (remove_path(path) && errno != ENOENT)
+               if (remove_path(path))
                        return -1;
        }
        return 0;
@@ -612,23 +599,6 @@ struct merge_file_info
                 merge:1;
 };
 
-static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
-{
-       unsigned long size;
-       enum object_type type;
-
-       if (!hashcmp(sha1, null_sha1)) {
-               mm->ptr = xstrdup("");
-               mm->size = 0;
-               return;
-       }
-
-       mm->ptr = read_sha1_file(sha1, &type, &size);
-       if (!mm->ptr || type != OBJ_BLOB)
-               die("unable to read blob object %s", sha1_to_hex(sha1));
-       mm->size = size;
-}
-
 static int merge_3way(struct merge_options *o,
                      mmbuffer_t *result_buf,
                      struct diff_filespec *one,
@@ -638,24 +608,46 @@ static int merge_3way(struct merge_options *o,
                      const char *branch2)
 {
        mmfile_t orig, src1, src2;
-       char *name1, *name2;
+       char *base_name, *name1, *name2;
        int merge_status;
+       int favor;
 
-       if (strcmp(a->path, b->path)) {
+       if (o->call_depth)
+               favor = 0;
+       else {
+               switch (o->recursive_variant) {
+               case MERGE_RECURSIVE_OURS:
+                       favor = XDL_MERGE_FAVOR_OURS;
+                       break;
+               case MERGE_RECURSIVE_THEIRS:
+                       favor = XDL_MERGE_FAVOR_THEIRS;
+                       break;
+               default:
+                       favor = 0;
+                       break;
+               }
+       }
+
+       if (strcmp(a->path, b->path) ||
+           (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
+               base_name = o->ancestor == NULL ? NULL :
+                       xstrdup(mkpath("%s:%s", o->ancestor, one->path));
                name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
                name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
        } else {
+               base_name = o->ancestor == NULL ? NULL :
+                       xstrdup(mkpath("%s", o->ancestor));
                name1 = xstrdup(mkpath("%s", branch1));
                name2 = xstrdup(mkpath("%s", branch2));
        }
 
-       fill_mm(one->sha1, &orig);
-       fill_mm(a->sha1, &src1);
-       fill_mm(b->sha1, &src2);
+       read_mmblob(&orig, one->sha1);
+       read_mmblob(&src1, a->sha1);
+       read_mmblob(&src2, b->sha1);
 
-       merge_status = ll_merge(result_buf, a->path, &orig,
+       merge_status = ll_merge(result_buf, a->path, &orig, base_name,
                                &src1, name1, &src2, name2,
-                               o->call_depth);
+                               (!!o->call_depth) | (favor << 1));
 
        free(name1);
        free(name2);
@@ -1064,6 +1056,53 @@ static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
        return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
 }
 
+static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
+{
+       void *buf;
+       enum object_type type;
+       unsigned long size;
+       buf = read_sha1_file(sha1, &type, &size);
+       if (!buf)
+               return error("cannot read object %s", sha1_to_hex(sha1));
+       if (type != OBJ_BLOB) {
+               free(buf);
+               return error("object %s is not a blob", sha1_to_hex(sha1));
+       }
+       strbuf_attach(dst, buf, size, size + 1);
+       return 0;
+}
+
+static int blob_unchanged(const unsigned char *o_sha,
+                         const unsigned char *a_sha,
+                         const char *path)
+{
+       struct strbuf o = STRBUF_INIT;
+       struct strbuf a = STRBUF_INIT;
+       int ret = 0; /* assume changed for safety */
+
+       if (sha_eq(o_sha, a_sha))
+               return 1;
+       if (!merge_renormalize)
+               return 0;
+
+       assert(o_sha && a_sha);
+       if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
+               goto error_return;
+       /*
+        * Note: binary | is used so that both renormalizations are
+        * performed.  Comparison can be skipped if both files are
+        * unchanged since their sha1s have already been compared.
+        */
+       if (renormalize_buffer(path, o.buf, o.len, &o) |
+           renormalize_buffer(path, a.buf, o.len, &a))
+               ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
+
+error_return:
+       strbuf_release(&o);
+       strbuf_release(&a);
+       return ret;
+}
+
 /* Per entry merge function */
 static int process_entry(struct merge_options *o,
                         const char *path, struct stage_data *entry)
@@ -1083,8 +1122,8 @@ static int process_entry(struct merge_options *o,
        if (o_sha && (!a_sha || !b_sha)) {
                /* Case A: Deleted in one */
                if ((!a_sha && !b_sha) ||
-                   (sha_eq(a_sha, o_sha) && !b_sha) ||
-                   (!a_sha && sha_eq(b_sha, o_sha))) {
+                   (!b_sha && blob_unchanged(o_sha, a_sha, path)) ||
+                   (!a_sha && blob_unchanged(o_sha, b_sha, path))) {
                        /* Deleted in both or deleted in one and
                         * unchanged in the other */
                        if (a_sha)
@@ -1186,6 +1225,28 @@ static int process_entry(struct merge_options *o,
        return clean_merge;
 }
 
+struct unpack_trees_error_msgs get_porcelain_error_msgs(void)
+{
+       struct unpack_trees_error_msgs msgs = {
+               /* would_overwrite */
+               "Your local changes to '%s' would be overwritten by merge.  Aborting.",
+               /* not_uptodate_file */
+               "Your local changes to '%s' would be overwritten by merge.  Aborting.",
+               /* not_uptodate_dir */
+               "Updating '%s' would lose untracked files in it.  Aborting.",
+               /* would_lose_untracked */
+               "Untracked working tree file '%s' would be %s by merge.  Aborting",
+               /* bind_overlap -- will not happen here */
+               NULL,
+       };
+       if (advice_commit_before_merge) {
+               msgs.would_overwrite = msgs.not_uptodate_file =
+                       "Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
+                       "Please, commit your changes or stash them before you can merge.";
+       }
+       return msgs;
+}
+
 int merge_trees(struct merge_options *o,
                struct tree *head,
                struct tree *merge,
@@ -1194,9 +1255,9 @@ int merge_trees(struct merge_options *o,
 {
        int code, clean;
 
-       if (o->subtree_merge) {
-               merge = shift_tree_object(head, merge);
-               common = shift_tree_object(head, common);
+       if (o->subtree_shift) {
+               merge = shift_tree_object(head, merge, o->subtree_shift);
+               common = shift_tree_object(head, common, o->subtree_shift);
        }
 
        if (sha_eq(common->object.sha1, merge->object.sha1)) {
@@ -1333,6 +1394,7 @@ int merge_recursive(struct merge_options *o,
        if (!o->call_depth)
                read_cache();
 
+       o->ancestor = "merged common ancestors";
        clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
                            &mrtree);