From db757e8b8d5527c195c461a04ec35d141ddea48e Mon Sep 17 00:00:00 2001 From: Elijah Newren Date: Wed, 2 Feb 2022 02:37:28 +0000 Subject: show, log: provide a --remerge-diff capability When this option is specified, we remerge all (two parent) merge commits and diff the actual merge commit to the automatically created version, in order to show how users removed conflict markers, resolved the different conflict versions, and potentially added new changes outside of conflict regions in order to resolve semantic merge problems (or, possibly, just to hide other random changes). This capability works by creating a temporary object directory and marking it as the primary object store. This makes it so that any blobs or trees created during the automatic merge are easily removable afterwards by just deleting all objects from the temporary object directory. There are a few ways that this implementation is suboptimal: * `log --remerge-diff` becomes slow, because the temporary object directory can fill with many loose objects while running * the log output can be muddied with misplaced "warning: cannot merge binary files" messages, since ll-merge.c unconditionally writes those messages to stderr while running instead of allowing callers to manage them. * important conflict and warning messages are simply dropped; thus for conflicts like modify/delete or rename/rename or file/directory which are not representable with content conflict markers, there may be no way for a user of --remerge-diff to know that there had been a conflict which was resolved (and which possibly motivated other changes in the merge commit). * when fixing the previous issue, note that some unimportant conflict and warning messages might start being included. We should instead make sure these remain dropped. Subsequent commits will address these issues. Signed-off-by: Elijah Newren Signed-off-by: Junio C Hamano --- revision.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'revision.h') diff --git a/revision.h b/revision.h index 5578bb4720..13178e6b8f 100644 --- a/revision.h +++ b/revision.h @@ -195,7 +195,8 @@ struct rev_info { combine_merges:1, combined_all_paths:1, dense_combined_merges:1, - first_parent_merges:1; + first_parent_merges:1, + remerge_diff:1; /* Format info */ int show_notes; -- cgit v1.2.3 From 7b90ab467a658b2fb1b7c15c7d634e06f35f4ef2 Mon Sep 17 00:00:00 2001 From: Elijah Newren Date: Wed, 2 Feb 2022 02:37:29 +0000 Subject: log: clean unneeded objects during `log --remerge-diff` The --remerge-diff option will need to create new blobs and trees representing the "automatic merge" state. If one is traversing a long project history, one can easily get hundreds of thousands of loose objects generated during `log --remerge-diff`. However, none of those loose objects are needed after we have completed our diff operation; they can be summarily deleted. Add a new helper function to tmp_objdir to discard all the contained objects, and call it after each merge is handled. Signed-off-by: Elijah Newren Signed-off-by: Junio C Hamano --- builtin/log.c | 13 +++++++------ log-tree.c | 8 +++++++- revision.h | 3 +++ tmp-objdir.c | 5 +++++ tmp-objdir.h | 6 ++++++ 5 files changed, 28 insertions(+), 7 deletions(-) (limited to 'revision.h') diff --git a/builtin/log.c b/builtin/log.c index a7d624f4a7..63d480b37b 100644 --- a/builtin/log.c +++ b/builtin/log.c @@ -422,13 +422,12 @@ static int cmd_log_walk(struct rev_info *rev) struct commit *commit; int saved_nrl = 0; int saved_dcctc = 0; - struct tmp_objdir *remerge_objdir = NULL; if (rev->remerge_diff) { - remerge_objdir = tmp_objdir_create("remerge-diff"); - if (!remerge_objdir) + rev->remerge_objdir = tmp_objdir_create("remerge-diff"); + if (!rev->remerge_objdir) die(_("unable to create temporary object directory")); - tmp_objdir_replace_primary_odb(remerge_objdir, 1); + tmp_objdir_replace_primary_odb(rev->remerge_objdir, 1); } if (rev->early_output) @@ -473,8 +472,10 @@ static int cmd_log_walk(struct rev_info *rev) rev->diffopt.no_free = 0; diff_free(&rev->diffopt); - if (rev->remerge_diff) - tmp_objdir_destroy(remerge_objdir); + if (rev->remerge_diff) { + tmp_objdir_destroy(rev->remerge_objdir); + rev->remerge_objdir = NULL; + } if (rev->diffopt.output_format & DIFF_FORMAT_CHECKDIFF && rev->diffopt.flags.check_failed) { diff --git a/log-tree.c b/log-tree.c index 8f762fb373..6b62ae1a6b 100644 --- a/log-tree.c +++ b/log-tree.c @@ -4,6 +4,7 @@ #include "diff.h" #include "object-store.h" #include "repository.h" +#include "tmp-objdir.h" #include "commit.h" #include "tag.h" #include "graph.h" @@ -946,7 +947,12 @@ static int do_remerge_diff(struct rev_info *opt, strbuf_release(&parent1_desc); strbuf_release(&parent2_desc); merge_finalize(&o, &res); - /* TODO: clean up the temporary object directory */ + + /* Clean up the contents of the temporary object directory */ + if (opt->remerge_objdir) + tmp_objdir_discard_objects(opt->remerge_objdir); + else + BUG("did a remerge diff without remerge_objdir?!?"); return !opt->loginfo; } diff --git a/revision.h b/revision.h index 13178e6b8f..44efce3f41 100644 --- a/revision.h +++ b/revision.h @@ -318,6 +318,9 @@ struct rev_info { /* misc. flags related to '--no-kept-objects' */ unsigned keep_pack_cache_flags; + + /* Location where temporary objects for remerge-diff are written. */ + struct tmp_objdir *remerge_objdir; }; int ref_excluded(struct string_list *, const char *path); diff --git a/tmp-objdir.c b/tmp-objdir.c index 3d38eeab66..adf6033549 100644 --- a/tmp-objdir.c +++ b/tmp-objdir.c @@ -79,6 +79,11 @@ static void remove_tmp_objdir_on_signal(int signo) raise(signo); } +void tmp_objdir_discard_objects(struct tmp_objdir *t) +{ + remove_dir_recursively(&t->path, REMOVE_DIR_KEEP_TOPLEVEL); +} + /* * These env_* functions are for setting up the child environment; the * "replace" variant overrides the value of any existing variable with that diff --git a/tmp-objdir.h b/tmp-objdir.h index cda5ec7677..76efc7edee 100644 --- a/tmp-objdir.h +++ b/tmp-objdir.h @@ -46,6 +46,12 @@ int tmp_objdir_migrate(struct tmp_objdir *); */ int tmp_objdir_destroy(struct tmp_objdir *); +/* + * Remove all objects from the temporary object directory, while leaving it + * around so more objects can be added. + */ +void tmp_objdir_discard_objects(struct tmp_objdir *); + /* * Add the temporary object directory as an alternate object store in the * current process. -- cgit v1.2.3