merge-ort: implement compute_collisions()
This is nearly a wholesale copy of compute_collisions() from merge-recursive.c, and the logic remains the same, but it has been tweaked slightly due to: * using strmap.h API (instead of direct hashmaps) * allocation/freeing of data structures were done separately in merge_start() and clear_or_reinit_internal_opts() in an earlier patch in this series * there is no non_unique_new_dir data field in merge-ort; that will be handled a different way It does depend on two new functions, apply_dir_rename() and check_dir_renamed() which were introduced with simple die-not-yet-implemented shells and will be implemented in subsequent patches. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Elijah Newren committed
Jan 19, 2021 at 19:53 UTC
d9d015df4a3d794ec889dc70902d28f3ca87d817
1 file changed
+67
-1
merge-ort.c
+67
-1
@@ -726,6 +726,19 @@ struct collision_info {
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unsigned reported_already:1;
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};
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+/*
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+ * Return a new string that replaces the beginning portion (which matches
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+ * rename_info->key), with rename_info->util.new_dir. In perl-speak:
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+ * new_path_name = (old_path =~ s/rename_info->key/rename_info->value/);
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+ * NOTE:
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+ * Caller must ensure that old_path starts with rename_info->key + '/'.
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+ */
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+static char *apply_dir_rename(struct strmap_entry *rename_info,
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+ const char *old_path)
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+{
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+ die("Not yet implemented!");
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+}
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+
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static void get_renamed_dir_portion(const char *old_path, const char *new_path,
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char **old_dir, char **new_dir)
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{
@@ -964,11 +977,64 @@ static void handle_directory_level_conflicts(struct merge_options *opt)
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string_list_clear(&duplicated, 0);
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}
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+static struct strmap_entry *check_dir_renamed(const char *path,
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+ struct strmap *dir_renames)
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+{
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+ die("Not yet implemented!");
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+}
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+
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static void compute_collisions(struct strmap *collisions,
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struct strmap *dir_renames,
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struct diff_queue_struct *pairs)
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{
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- die("Not yet implemented.");
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+ int i;
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+
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+ strmap_init_with_options(collisions, NULL, 0);
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+ if (strmap_empty(dir_renames))
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+ return;
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+
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+ /*
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+ * Multiple files can be mapped to the same path due to directory
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+ * renames done by the other side of history. Since that other
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+ * side of history could have merged multiple directories into one,
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+ * if our side of history added the same file basename to each of
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+ * those directories, then all N of them would get implicitly
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+ * renamed by the directory rename detection into the same path,
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+ * and we'd get an add/add/.../add conflict, and all those adds
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+ * from *this* side of history. This is not representable in the
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+ * index, and users aren't going to easily be able to make sense of
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+ * it. So we need to provide a good warning about what's
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+ * happening, and fall back to no-directory-rename detection
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+ * behavior for those paths.
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+ *
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+ * See testcases 9e and all of section 5 from t6043 for examples.
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+ */
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+ for (i = 0; i < pairs->nr; ++i) {
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+ struct strmap_entry *rename_info;
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+ struct collision_info *collision_info;
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+ char *new_path;
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+ struct diff_filepair *pair = pairs->queue[i];
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+
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+ if (pair->status != 'A' && pair->status != 'R')
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+ continue;
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+ rename_info = check_dir_renamed(pair->two->path, dir_renames);
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+ if (!rename_info)
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+ continue;
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+
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+ new_path = apply_dir_rename(rename_info, pair->two->path);
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+ assert(new_path);
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+ collision_info = strmap_get(collisions, new_path);
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+ if (collision_info) {
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+ free(new_path);
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+ } else {
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+ collision_info = xcalloc(1,
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+ sizeof(struct collision_info));
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+ string_list_init(&collision_info->source_files, 0);
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+ strmap_put(collisions, new_path, collision_info);
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+ }
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+ string_list_insert(&collision_info->source_files,
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+ pair->two->path);
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+ }
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}
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static char *check_for_directory_rename(struct merge_options *opt,