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Merge branch 'en/diffcore-rename'
Performance optimization work on the rename detection continues. * en/diffcore-rename: merge-ort: call diffcore_rename() directly gitdiffcore doc: mention new preliminary step for rename detection diffcore-rename: guide inexact rename detection based on basenames diffcore-rename: complete find_basename_matches() diffcore-rename: compute basenames of source and dest candidates t4001: add a test comparing basename similarity and content similarity diffcore-rename: filter rename_src list when possible diffcore-rename: no point trying to find a match better than exact
This commit is contained in:
Junio C Hamano
commit
12bd17521c
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@ -169,6 +169,26 @@ a similarity score different from the default of 50% by giving a
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number after the "-M" or "-C" option (e.g. "-M8" to tell it to use
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8/10 = 80%).
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Note that when rename detection is on but both copy and break
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detection are off, rename detection adds a preliminary step that first
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checks if files are moved across directories while keeping their
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filename the same. If there is a file added to a directory whose
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contents is sufficiently similar to a file with the same name that got
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deleted from a different directory, it will mark them as renames and
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exclude them from the later quadratic step (the one that pairwise
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compares all unmatched files to find the "best" matches, determined by
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the highest content similarity). So, for example, if a deleted
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docs/ext.txt and an added docs/config/ext.txt are similar enough, they
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will be marked as a rename and prevent an added docs/ext.md that may
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be even more similar to the deleted docs/ext.txt from being considered
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as the rename destination in the later step. For this reason, the
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preliminary "match same filename" step uses a bit higher threshold to
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mark a file pair as a rename and stop considering other candidates for
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better matches. At most, one comparison is done per file in this
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preliminary pass; so if there are several remaining ext.txt files
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throughout the directory hierarchy after exact rename detection, this
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preliminary step will be skipped for those files.
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Note. When the "-C" option is used with `--find-copies-harder`
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option, 'git diff-{asterisk}' commands feed unmodified filepairs to
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diffcore mechanism as well as modified ones. This lets the copy
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@ -367,6 +367,144 @@ static int find_exact_renames(struct diff_options *options)
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return renames;
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}
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static const char *get_basename(const char *filename)
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{
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/*
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* gitbasename() has to worry about special drives, multiple
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* directory separator characters, trailing slashes, NULL or
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* empty strings, etc. We only work on filenames as stored in
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* git, and thus get to ignore all those complications.
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*/
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const char *base = strrchr(filename, '/');
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return base ? base + 1 : filename;
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}
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static int find_basename_matches(struct diff_options *options,
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int minimum_score)
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{
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/*
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* When I checked in early 2020, over 76% of file renames in linux
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* just moved files to a different directory but kept the same
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* basename. gcc did that with over 64% of renames, gecko did it
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* with over 79%, and WebKit did it with over 89%.
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*
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* Therefore we can bypass the normal exhaustive NxM matrix
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* comparison of similarities between all potential rename sources
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* and destinations by instead using file basename as a hint (i.e.
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* the portion of the filename after the last '/'), checking for
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* similarity between files with the same basename, and if we find
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* a pair that are sufficiently similar, record the rename pair and
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* exclude those two from the NxM matrix.
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*
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* This *might* cause us to find a less than optimal pairing (if
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* there is another file that we are even more similar to but has a
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* different basename). Given the huge performance advantage
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* basename matching provides, and given the frequency with which
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* people use the same basename in real world projects, that's a
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* trade-off we are willing to accept when doing just rename
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* detection.
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*
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* If someone wants copy detection that implies they are willing to
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* spend more cycles to find similarities between files, so it may
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* be less likely that this heuristic is wanted. If someone is
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* doing break detection, that means they do not want filename
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* similarity to imply any form of content similiarity, and thus
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* this heuristic would definitely be incompatible.
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*/
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int i, renames = 0;
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struct strintmap sources;
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struct strintmap dests;
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struct hashmap_iter iter;
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struct strmap_entry *entry;
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/*
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* The prefeteching stuff wants to know if it can skip prefetching
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* blobs that are unmodified...and will then do a little extra work
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* to verify that the oids are indeed different before prefetching.
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* Unmodified blobs are only relevant when doing copy detection;
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* when limiting to rename detection, diffcore_rename[_extended]()
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* will never be called with unmodified source paths fed to us, so
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* the extra work necessary to check if rename_src entries are
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* unmodified would be a small waste.
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*/
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int skip_unmodified = 0;
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/*
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* Create maps of basename -> fullname(s) for remaining sources and
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* dests.
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*/
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strintmap_init_with_options(&sources, -1, NULL, 0);
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strintmap_init_with_options(&dests, -1, NULL, 0);
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for (i = 0; i < rename_src_nr; ++i) {
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char *filename = rename_src[i].p->one->path;
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const char *base;
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/* exact renames removed in remove_unneeded_paths_from_src() */
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assert(!rename_src[i].p->one->rename_used);
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/* Record index within rename_src (i) if basename is unique */
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base = get_basename(filename);
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if (strintmap_contains(&sources, base))
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strintmap_set(&sources, base, -1);
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else
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strintmap_set(&sources, base, i);
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}
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for (i = 0; i < rename_dst_nr; ++i) {
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char *filename = rename_dst[i].p->two->path;
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const char *base;
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if (rename_dst[i].is_rename)
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continue; /* involved in exact match already. */
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/* Record index within rename_dst (i) if basename is unique */
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base = get_basename(filename);
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if (strintmap_contains(&dests, base))
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strintmap_set(&dests, base, -1);
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else
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strintmap_set(&dests, base, i);
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}
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/* Now look for basename matchups and do similarity estimation */
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strintmap_for_each_entry(&sources, &iter, entry) {
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const char *base = entry->key;
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intptr_t src_index = (intptr_t)entry->value;
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intptr_t dst_index;
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if (src_index == -1)
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continue;
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if (0 <= (dst_index = strintmap_get(&dests, base))) {
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struct diff_filespec *one, *two;
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int score;
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/* Estimate the similarity */
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one = rename_src[src_index].p->one;
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two = rename_dst[dst_index].p->two;
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score = estimate_similarity(options->repo, one, two,
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minimum_score, skip_unmodified);
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/* If sufficiently similar, record as rename pair */
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if (score < minimum_score)
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continue;
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record_rename_pair(dst_index, src_index, score);
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renames++;
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/*
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* Found a rename so don't need text anymore; if we
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* didn't find a rename, the filespec_blob would get
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* re-used when doing the matrix of comparisons.
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*/
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diff_free_filespec_blob(one);
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diff_free_filespec_blob(two);
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}
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}
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strintmap_clear(&sources);
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strintmap_clear(&dests);
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return renames;
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}
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#define NUM_CANDIDATE_PER_DST 4
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static void record_if_better(struct diff_score m[], struct diff_score *o)
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{
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@ -454,6 +592,54 @@ static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, i
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return count;
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}
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static void remove_unneeded_paths_from_src(int detecting_copies)
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{
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int i, new_num_src;
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if (detecting_copies)
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return; /* nothing to remove */
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if (break_idx)
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return; /* culling incompatible with break detection */
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/*
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* Note on reasons why we cull unneeded sources but not destinations:
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* 1) Pairings are stored in rename_dst (not rename_src), which we
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* need to keep around. So, we just can't cull rename_dst even
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* if we wanted to. But doing so wouldn't help because...
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*
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* 2) There is a matrix pairwise comparison that follows the
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* "Performing inexact rename detection" progress message.
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* Iterating over the destinations is done in the outer loop,
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* hence we only iterate over each of those once and we can
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* easily skip the outer loop early if the destination isn't
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* relevant. That's only one check per destination path to
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* skip.
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*
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* By contrast, the sources are iterated in the inner loop; if
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* we check whether a source can be skipped, then we'll be
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* checking it N separate times, once for each destination.
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* We don't want to have to iterate over known-not-needed
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* sources N times each, so avoid that by removing the sources
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* from rename_src here.
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*/
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for (i = 0, new_num_src = 0; i < rename_src_nr; i++) {
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/*
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* renames are stored in rename_dst, so if a rename has
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* already been detected using this source, we can just
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* remove the source knowing rename_dst has its info.
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*/
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if (rename_src[i].p->one->rename_used)
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continue;
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if (new_num_src < i)
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memcpy(&rename_src[new_num_src], &rename_src[i],
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sizeof(struct diff_rename_src));
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new_num_src++;
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}
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rename_src_nr = new_num_src;
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}
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void diffcore_rename(struct diff_options *options)
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{
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int detect_rename = options->detect_rename;
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@ -463,9 +649,11 @@ void diffcore_rename(struct diff_options *options)
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struct diff_score *mx;
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int i, j, rename_count, skip_unmodified = 0;
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int num_destinations, dst_cnt;
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int num_sources, want_copies;
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struct progress *progress = NULL;
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trace2_region_enter("diff", "setup", options->repo);
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want_copies = (detect_rename == DIFF_DETECT_COPY);
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if (!minimum_score)
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minimum_score = DEFAULT_RENAME_SCORE;
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@ -502,7 +690,7 @@ void diffcore_rename(struct diff_options *options)
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p->one->rename_used++;
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register_rename_src(p);
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}
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else if (detect_rename == DIFF_DETECT_COPY) {
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else if (want_copies) {
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/*
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* Increment the "rename_used" score by
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* one, to indicate ourselves as a user.
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@ -527,17 +715,60 @@ void diffcore_rename(struct diff_options *options)
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if (minimum_score == MAX_SCORE)
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goto cleanup;
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/*
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* Calculate how many renames are left (but all the source
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* files still remain as options for rename/copies!)
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*/
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num_sources = rename_src_nr;
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if (want_copies || break_idx) {
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/*
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* Cull sources:
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* - remove ones corresponding to exact renames
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*/
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trace2_region_enter("diff", "cull after exact", options->repo);
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remove_unneeded_paths_from_src(want_copies);
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trace2_region_leave("diff", "cull after exact", options->repo);
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} else {
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/* Determine minimum score to match basenames */
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double factor = 0.5;
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char *basename_factor = getenv("GIT_BASENAME_FACTOR");
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int min_basename_score;
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if (basename_factor)
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factor = strtol(basename_factor, NULL, 10)/100.0;
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assert(factor >= 0.0 && factor <= 1.0);
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min_basename_score = minimum_score +
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(int)(factor * (MAX_SCORE - minimum_score));
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/*
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* Cull sources:
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* - remove ones involved in renames (found via exact match)
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*/
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trace2_region_enter("diff", "cull after exact", options->repo);
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remove_unneeded_paths_from_src(want_copies);
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trace2_region_leave("diff", "cull after exact", options->repo);
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|
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/* Utilize file basenames to quickly find renames. */
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trace2_region_enter("diff", "basename matches", options->repo);
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rename_count += find_basename_matches(options,
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min_basename_score);
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trace2_region_leave("diff", "basename matches", options->repo);
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|
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/*
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* Cull sources, again:
|
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* - remove ones involved in renames (found via basenames)
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*/
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trace2_region_enter("diff", "cull basename", options->repo);
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remove_unneeded_paths_from_src(want_copies);
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trace2_region_leave("diff", "cull basename", options->repo);
|
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}
|
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|
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/* Calculate how many rename destinations are left */
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num_destinations = (rename_dst_nr - rename_count);
|
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num_sources = rename_src_nr; /* rename_src_nr reflects lower number */
|
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|
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/* All done? */
|
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if (!num_destinations)
|
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if (!num_destinations || !num_sources)
|
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goto cleanup;
|
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|
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switch (too_many_rename_candidates(num_destinations, rename_src_nr,
|
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switch (too_many_rename_candidates(num_destinations, num_sources,
|
||||
options)) {
|
||||
case 1:
|
||||
goto cleanup;
|
||||
|
|
@ -553,7 +784,7 @@ void diffcore_rename(struct diff_options *options)
|
|||
if (options->show_rename_progress) {
|
||||
progress = start_delayed_progress(
|
||||
_("Performing inexact rename detection"),
|
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(uint64_t)num_destinations * (uint64_t)rename_src_nr);
|
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(uint64_t)num_destinations * (uint64_t)num_sources);
|
||||
}
|
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|
||||
mx = xcalloc(st_mult(NUM_CANDIDATE_PER_DST, num_destinations),
|
||||
|
|
@ -563,7 +794,7 @@ void diffcore_rename(struct diff_options *options)
|
|||
struct diff_score *m;
|
||||
|
||||
if (rename_dst[i].is_rename)
|
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continue; /* dealt with exact match already. */
|
||||
continue; /* exact or basename match already handled */
|
||||
|
||||
m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST];
|
||||
for (j = 0; j < NUM_CANDIDATE_PER_DST; j++)
|
||||
|
|
@ -573,6 +804,8 @@ void diffcore_rename(struct diff_options *options)
|
|||
struct diff_filespec *one = rename_src[j].p->one;
|
||||
struct diff_score this_src;
|
||||
|
||||
assert(!one->rename_used || want_copies || break_idx);
|
||||
|
||||
if (skip_unmodified &&
|
||||
diff_unmodified_pair(rename_src[j].p))
|
||||
continue;
|
||||
|
|
@ -594,7 +827,7 @@ void diffcore_rename(struct diff_options *options)
|
|||
}
|
||||
dst_cnt++;
|
||||
display_progress(progress,
|
||||
(uint64_t)dst_cnt * (uint64_t)rename_src_nr);
|
||||
(uint64_t)dst_cnt * (uint64_t)num_sources);
|
||||
}
|
||||
stop_progress(&progress);
|
||||
|
||||
|
|
@ -602,7 +835,7 @@ void diffcore_rename(struct diff_options *options)
|
|||
STABLE_QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare);
|
||||
|
||||
rename_count += find_renames(mx, dst_cnt, minimum_score, 0);
|
||||
if (detect_rename == DIFF_DETECT_COPY)
|
||||
if (want_copies)
|
||||
rename_count += find_renames(mx, dst_cnt, minimum_score, 1);
|
||||
free(mx);
|
||||
trace2_region_leave("diff", "inexact renames", options->repo);
|
||||
|
|
|
|||
66
merge-ort.c
66
merge-ort.c
|
|
@ -535,6 +535,23 @@ static void setup_path_info(struct merge_options *opt,
|
|||
result->util = mi;
|
||||
}
|
||||
|
||||
static void add_pair(struct merge_options *opt,
|
||||
struct name_entry *names,
|
||||
const char *pathname,
|
||||
unsigned side,
|
||||
unsigned is_add /* if false, is_delete */)
|
||||
{
|
||||
struct diff_filespec *one, *two;
|
||||
struct rename_info *renames = &opt->priv->renames;
|
||||
int names_idx = is_add ? side : 0;
|
||||
|
||||
one = alloc_filespec(pathname);
|
||||
two = alloc_filespec(pathname);
|
||||
fill_filespec(is_add ? two : one,
|
||||
&names[names_idx].oid, 1, names[names_idx].mode);
|
||||
diff_queue(&renames->pairs[side], one, two);
|
||||
}
|
||||
|
||||
static void collect_rename_info(struct merge_options *opt,
|
||||
struct name_entry *names,
|
||||
const char *dirname,
|
||||
|
|
@ -544,6 +561,7 @@ static void collect_rename_info(struct merge_options *opt,
|
|||
unsigned match_mask)
|
||||
{
|
||||
struct rename_info *renames = &opt->priv->renames;
|
||||
unsigned side;
|
||||
|
||||
/* Update dirs_removed, as needed */
|
||||
if (dirmask == 1 || dirmask == 3 || dirmask == 5) {
|
||||
|
|
@ -554,6 +572,21 @@ static void collect_rename_info(struct merge_options *opt,
|
|||
if (sides & 2)
|
||||
strset_add(&renames->dirs_removed[2], fullname);
|
||||
}
|
||||
|
||||
if (filemask == 0 || filemask == 7)
|
||||
return;
|
||||
|
||||
for (side = MERGE_SIDE1; side <= MERGE_SIDE2; ++side) {
|
||||
unsigned side_mask = (1 << side);
|
||||
|
||||
/* Check for deletion on side */
|
||||
if ((filemask & 1) && !(filemask & side_mask))
|
||||
add_pair(opt, names, fullname, side, 0 /* delete */);
|
||||
|
||||
/* Check for addition on side */
|
||||
if (!(filemask & 1) && (filemask & side_mask))
|
||||
add_pair(opt, names, fullname, side, 1 /* add */);
|
||||
}
|
||||
}
|
||||
|
||||
static int collect_merge_info_callback(int n,
|
||||
|
|
@ -2079,6 +2112,27 @@ static int process_renames(struct merge_options *opt,
|
|||
return clean_merge;
|
||||
}
|
||||
|
||||
static void resolve_diffpair_statuses(struct diff_queue_struct *q)
|
||||
{
|
||||
/*
|
||||
* A simplified version of diff_resolve_rename_copy(); would probably
|
||||
* just use that function but it's static...
|
||||
*/
|
||||
int i;
|
||||
struct diff_filepair *p;
|
||||
|
||||
for (i = 0; i < q->nr; ++i) {
|
||||
p = q->queue[i];
|
||||
p->status = 0; /* undecided */
|
||||
if (!DIFF_FILE_VALID(p->one))
|
||||
p->status = DIFF_STATUS_ADDED;
|
||||
else if (!DIFF_FILE_VALID(p->two))
|
||||
p->status = DIFF_STATUS_DELETED;
|
||||
else if (DIFF_PAIR_RENAME(p))
|
||||
p->status = DIFF_STATUS_RENAMED;
|
||||
}
|
||||
}
|
||||
|
||||
static int compare_pairs(const void *a_, const void *b_)
|
||||
{
|
||||
const struct diff_filepair *a = *((const struct diff_filepair **)a_);
|
||||
|
|
@ -2089,8 +2143,6 @@ static int compare_pairs(const void *a_, const void *b_)
|
|||
|
||||
/* Call diffcore_rename() to compute which files have changed on given side */
|
||||
static void detect_regular_renames(struct merge_options *opt,
|
||||
struct tree *merge_base,
|
||||
struct tree *side,
|
||||
unsigned side_index)
|
||||
{
|
||||
struct diff_options diff_opts;
|
||||
|
|
@ -2108,11 +2160,11 @@ static void detect_regular_renames(struct merge_options *opt,
|
|||
diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
|
||||
diff_setup_done(&diff_opts);
|
||||
|
||||
diff_queued_diff = renames->pairs[side_index];
|
||||
trace2_region_enter("diff", "diffcore_rename", opt->repo);
|
||||
diff_tree_oid(&merge_base->object.oid, &side->object.oid, "",
|
||||
&diff_opts);
|
||||
diffcore_std(&diff_opts);
|
||||
diffcore_rename(&diff_opts);
|
||||
trace2_region_leave("diff", "diffcore_rename", opt->repo);
|
||||
resolve_diffpair_statuses(&diff_queued_diff);
|
||||
|
||||
if (diff_opts.needed_rename_limit > renames->needed_limit)
|
||||
renames->needed_limit = diff_opts.needed_rename_limit;
|
||||
|
|
@ -2212,8 +2264,8 @@ static int detect_and_process_renames(struct merge_options *opt,
|
|||
memset(&combined, 0, sizeof(combined));
|
||||
|
||||
trace2_region_enter("merge", "regular renames", opt->repo);
|
||||
detect_regular_renames(opt, merge_base, side1, MERGE_SIDE1);
|
||||
detect_regular_renames(opt, merge_base, side2, MERGE_SIDE2);
|
||||
detect_regular_renames(opt, MERGE_SIDE1);
|
||||
detect_regular_renames(opt, MERGE_SIDE2);
|
||||
trace2_region_leave("merge", "regular renames", opt->repo);
|
||||
|
||||
trace2_region_enter("merge", "directory renames", opt->repo);
|
||||
|
|
|
|||
|
|
@ -262,4 +262,28 @@ test_expect_success 'diff-tree -l0 defaults to a big rename limit, not zero' '
|
|||
grep "myotherfile.*myfile" actual
|
||||
'
|
||||
|
||||
test_expect_success 'basename similarity vs best similarity' '
|
||||
mkdir subdir &&
|
||||
test_write_lines line1 line2 line3 line4 line5 \
|
||||
line6 line7 line8 line9 line10 >subdir/file.txt &&
|
||||
git add subdir/file.txt &&
|
||||
git commit -m "base txt" &&
|
||||
|
||||
git rm subdir/file.txt &&
|
||||
test_write_lines line1 line2 line3 line4 line5 \
|
||||
line6 line7 line8 >file.txt &&
|
||||
test_write_lines line1 line2 line3 line4 line5 \
|
||||
line6 line7 line8 line9 >file.md &&
|
||||
git add file.txt file.md &&
|
||||
git commit -a -m "rename" &&
|
||||
git diff-tree -r -M --name-status HEAD^ HEAD >actual &&
|
||||
# subdir/file.txt is 88% similar to file.md, 78% similar to file.txt,
|
||||
# but since same basenames are checked first...
|
||||
cat >expected <<-\EOF &&
|
||||
A file.md
|
||||
R078 subdir/file.txt file.txt
|
||||
EOF
|
||||
test_cmp expected actual
|
||||
'
|
||||
|
||||
test_done
|
||||
|
|
|
|||
Loading…
Reference in a new issue