@matheusbsbs / matheus-bagliano / commits / fe83269e16

resolve-undo: allow resurrecting conflicted state that resolved to deletion

The resolve-undo index extension records up to three (mode, object name) tuples for non-zero stages for each path that was resolved, to be used to recreate the original conflicted state later when the user requests. The unmerge_index_entry_at() function uses the resolve-undo data to do so, but it assumes that the path for which the conflicted state needs to be recreated can be specified by the position in the active_cache[] array. This obviously cannot salvage the state of conflicted paths that were resolved by removing them. For example, a delete-modify conflict, in which the change whose "modify" side made is a trivial typofix, may legitimately be resolved to remove the path, and resolve-undo extension does record the two (mode, object name) tuples for the common ancestor version and their version, lacking our version. But after recording such a removal of the path, you should be able to use resolve-undo data to recreate the conflicted state. Introduce a new unmerge_index_entry() helper function that takes the path (which does not necessarily have to exist in the active_cache[] array) and resolve-undo data, and use it to reimplement unmerge_index() public function that is used by "git rerere". The limited interface is still kept for now, as it is used by "git checkout -m" and "git update-index --unmerge", but these two codepaths will be updated to lift the assumption to allow conflicts that resolved to deletion can be recreated. Signed-off-by: Junio C Hamano <gitster@pobox.com>

Junio C Hamano committed Jul 31, 2023 at 15:44 UTC fe83269e16c1fd57df42c2a22a2b9ee621175a75

2 files changed +44 -5

resolve-undo.c

+43 -5

@@ -182,19 +182,57 @@ void unmerge_marked_index(struct index_state *istate)

182 }

183 }

184

185 +int unmerge_index_entry(struct index_state *istate, const char *path,

186 + struct resolve_undo_info *ru)

187 +{

188 + int i = index_name_pos(istate, path, strlen(path));

189 +

190 + if (i < 0) {

191 + /* unmerged? */

192 + i = -i - 1;

193 + if (i < istate->cache_nr &&

194 + !strcmp(istate->cache[i]->name, path))

195 + /* yes, it is already unmerged */

196 + return 0;

197 + /* fallthru: resolved to removal */

198 + } else {

199 + /* merged - remove it to replace it with unmerged entries */

200 + remove_index_entry_at(istate, i);

201 + }

202 +

203 + for (i = 0; i < 3; i++) {

204 + struct cache_entry *ce;

205 + if (!ru->mode[i])

206 + continue;

207 + ce = make_cache_entry(istate, ru->mode[i], &ru->oid[i],

208 + path, i + 1, 0);

209 + if (add_index_entry(istate, ce, ADD_CACHE_OK_TO_ADD))

210 + return error("cannot unmerge '%s'", path);

211 + }

212 + return 0;

213 +}

214 +

215 void unmerge_index(struct index_state *istate, const struct pathspec *pathspec)

216 {

187 - int i;

217 + struct string_list_item *item;

218

219 if (!istate->resolve_undo)

220 return;

221

222 /* TODO: audit for interaction with sparse-index. */

223 ensure_full_index(istate);

194 - for (i = 0; i < istate->cache_nr; i++) {

195 - const struct cache_entry *ce = istate->cache[i];

196 - if (!ce_path_match(istate, ce, pathspec, NULL))

224 +

225 + for_each_string_list_item(item, istate->resolve_undo) {

226 + const char *path = item->string;

227 + struct resolve_undo_info *ru = item->util;

228 + if (!item->util)

229 + continue;

230 + if (!match_pathspec(istate, pathspec,

231 + item->string, strlen(item->string),

232 + 0, NULL, 0))

233 continue;

198 - i = unmerge_index_entry_at(istate, i);

234 + unmerge_index_entry(istate, path, ru);

235 + free(ru);

236 + item->util = NULL;

237 }

238 }

resolve-undo.h

@@ -18,6 +18,7 @@ void resolve_undo_write(struct strbuf *, struct string_list *);

18 struct string_list *resolve_undo_read(const char *, unsigned long);

19 void resolve_undo_clear_index(struct index_state *);

20 int unmerge_index_entry_at(struct index_state *, int);

21 +int unmerge_index_entry(struct index_state *, const char *, struct resolve_undo_info *);

22 void unmerge_index(struct index_state *, const struct pathspec *);

23 void unmerge_marked_index(struct index_state *);