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* Merge branch 'rc/histogram-diff'Junio C Hamano2011-09-06
|\ | | | | | | | | * rc/histogram-diff: xdiff/xprepare: initialise xdlclassifier_t cf in xdl_prepare_env()
| * xdiff/xprepare: initialise xdlclassifier_t cf in xdl_prepare_env()Tay Ray Chuan2011-08-31
| | | | | | | | | | | | | | | | | | | | Ensure that the xdl_free_classifier() call on xdlclassifier_t cf is safe even if xdl_init_classifier() isn't called. This may occur in the case where diff is run with --histogram and a call to, say, xdl_prepare_ctx() fails. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | Merge branch 'rc/histogram-diff' into HEADJunio C Hamano2011-08-17
|\ \ | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * rc/histogram-diff: xdiff/xhistogram: drop need for additional variable xdiff/xhistogram: rely on xdl_trim_ends() xdiff/xhistogram: rework handling of recursed results xdiff: do away with xdl_mmfile_next() Make test number unique xdiff/xprepare: use a smaller sample size for histogram diff xdiff/xprepare: skip classification teach --histogram to diff t4033-diff-patience: factor out tests xdiff/xpatience: factor out fall-back-diff function xdiff/xprepare: refactor abort cleanups xdiff/xprepare: use memset() Conflicts: xdiff/xprepare.c
| * xdiff/xhistogram: drop need for additional variableTay Ray Chuan2011-08-08
| | | | | | | | | | | | | | | | Having an additional variable (ptr) instead of changing line(1|2) and count(1|2) was for debugging purposes. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xdiff/xhistogram: rely on xdl_trim_ends()Tay Ray Chuan2011-08-08
| | | | | | | | | | | | | | | | | | Do away with reduce_common_start_end() and use xdf->dstart and xdf->dend set by xdl_trim_ends() that similarly tells us where the first unmatched line from the start and end occurs. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xdiff/xhistogram: rework handling of recursed resultsTay Ray Chuan2011-08-08
| | | | | | | | | | | | | | | | | | Previously we were over-complicating matters by trying to combine the recursed results. Now, terminate immediately if a recursive call failed and return its result. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xdiff: do away with xdl_mmfile_next()Tay Ray Chuan2011-08-03
| | | | | | | | | | | | | | | | Given our simple mmfile structure, xdl_mmfile_next() calls are redundant. Do away with calls to them. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xdiff/xprepare: use a smaller sample size for histogram diffTay Ray Chuan2011-07-12
| | | | | | | | | | | | | | | | | | | | | | | | For histogram diff, we can afford a smaller sample size and thus a poorer estimate of the number of lines, as the hash table (rhash) won't be filled up/grown. This is safe as the final count of lines (xdf.nrecs) will be updated correctly anyway by xdl_prepare_ctx(). This gives us a small boost in performance. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xdiff/xprepare: skip classificationTay Ray Chuan2011-07-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | xdiff performs "classification" of records (xdl_classify_record()), replacing hashes (xrecord_t.ha) with a unique identifier of the record/line and building a hash table (xrecord_t.rhash) of records. This is then used to "cleanup" records (xdl_cleanup_records()). We don't need any of that in histogram diff, so we omit calls to these functions. We also skip allocating memory to the hash table, rhash, as it is no longer used. This gives us a small boost in performance. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * teach --histogram to diffTay Ray Chuan2011-07-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Port JGit's HistogramDiff algorithm over to C. Rough numbers (TODO) show that it is faster than its --patience cousin, as well as the default Meyers algorithm. The implementation has been reworked to use structs and pointers, instead of bitmasks, thus doing away with JGit's 2^28 line limit. We also use xdiff's default hash table implementation (xdl_hash_bits() with XDL_HASHLONG()) for convenience. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xdiff/xpatience: factor out fall-back-diff functionTay Ray Chuan2011-07-07
| | | | | | | | | | | | | | | | This is in preparation for the histogram diff algorithm, which will also re-use much of the code to call the default Meyers diff algorithm. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xdiff/xprepare: refactor abort cleanupsTay Ray Chuan2011-07-07
| | | | | | | | | | | | | | | | | | | | | | Group free()'s that are called when a malloc() fails in xdl_prepare_ctx(), making for more readable code. Also add a free() on ha, in case future git hackers add allocs after the ha malloc. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xdiff/xprepare: use memset()Tay Ray Chuan2011-07-07
| | | | | | | | | | | | | | | | Use memset() instead of a for loop to initialize. This could give a performance advantage. Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | xdiff/xprepare: improve O(n*m) performance in xdl_cleanup_records()Tay Ray Chuan2011-08-17
|/ | | | | | | | | | | | | In xdl_cleanup_records(), we see O(n*m) performance, where n is the number of records from xdf->dstart to xdf->dend, and m is the size of a bucket in xdf->rhash (<= by mlim). Here, we improve this to O(n) by pre-computing nm (in rcrec->len(1|2)) in xdl_classify_record(). Reported-by: Marat Radchenko <marat@slonopotamus.org> Signed-off-by: Tay Ray Chuan <rctay89@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* Merge branch 'cb/diff-fname-optim'Junio C Hamano2010-11-17
|\ | | | | | | | | | | | | * cb/diff-fname-optim: diff: avoid repeated scanning while looking for funcname do not search functions for patch ID add rebase patch id tests
| * diff: avoid repeated scanning while looking for funcnameRené Scharfe2010-09-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For each hunk, xdl_find_func searches the preimage for a function name until the beginning of the file. If the file does not contain any function names, this search has complexity O(n^2) in the number of hunks n. Instead, inline xdl_find_func() and keep track of up to which line we have scanned already and the contents of the last funcname line that we have found. Noticed and a different approach proposed by Clemens Buchacher. This alternative solution was done by René Scharfe. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | xdiff: cast arguments for ctype functions to unsigned charJonathan Nieder2010-10-06
|/ | | | | | | | | | | | | | | | The ctype functions isspace(), isalnum(), et al take an integer argument representing an unsigned character, or -1 for EOF. On platforms with a signed char, it is unsafe to pass a char to them without casting it to unsigned char first. Most of git is already shielded against this by the ctype implementation in git-compat-util.h, but xdiff, which uses libc ctype.h, ought to be fixed. Noticed-by: der Mouse <mouse@Rodents-Montreal.ORG> Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* xdiff: optimise for no whitespace difference when ignoring whitespace.Dylan Reid2010-07-05
| | | | | | | | | | | | In xdl_recmatch, do the memcmp to check if the two lines are equal before checking if whitespace flags are set. If the lines are identical, then there is no need to check if they differ only in whitespace. This makes the common case (there is no whitespace difference) faster. It costs the case where lines are the same length and contain whitespace differences, but the common case is more than 20% faster. Signed-off-by: Dylan Reid <dgreid@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* xdiff/xmerge.c: use memset() instead of explicit for-loopAlexey Mahotkin2010-05-01
| | | | | | | | memset() is heavily optimized, and resulting assembler code is about 150 lines less for that file. Signed-off-by: Alexey Mahotkin <squadette@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* xdl_merge(): move file1 and file2 labels to xmparam structureJonathan Nieder2010-03-20
| | | | | | | | | | | | | | The labels for the three participants in a potential conflict are all optional arguments for the xdiff merge routine; if they are NULL, then xdl_merge() can cope by omitting the labels from its output. Move them to the xmparam structure to allow new callers to save some keystrokes where they are not needed. This also has the virtue of making the xdiff merge interface more similar to merge_trees, which might make it easier to learn. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* xdl_merge(): add optional ancestor label to diff3-style outputJonathan Nieder2010-03-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ‘git checkout --conflict=diff3’ command can be used to present conflicts hunks including text from the common ancestor: <<<<<<< ours ourside ||||||| original ======= theirside >>>>>>> theirs The added information is helpful for resolving merges by hand, and merge tools can usually grok it because it is very similar to the output from diff3 -m. A subtle change can help more tools to understand the output. ‘diff3’ includes the name of the merge base on the ||||||| line of the output, and some tools misparse the conflict hunks without it. Add a new xmp->ancestor parameter to xdl_merge() for use with conflict style XDL_MERGE_DIFF3 as a label on the ||||||| line for any conflict hunks. If xmp->ancestor is NULL, the output format is unchanged. Thus, this change only provides unexposed plumbing for the new feature; it does not affect the outward behavior of git. Requested-by: Stefan Monnier <monnier@iro.umontreal.ca> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Acked-by: Bert Wesarg <Bert.Wesarg@googlemail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* refactor merge flags into xmparam_tBert Wesarg2010-03-02
| | | | | | | | | Include the merge level, favor, and style flags into the xmparam_t struct. This removes the bit twiddling with these three values into the one flags parameter. Signed-off-by: Bert Wesarg <bert.wesarg@googlemail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* make union merge an xdl merge favorBert Wesarg2010-03-02
| | | | | | | | | The current union merge driver is implemented as an post process. But the xdl_merge code is quite capable to produce the result by itself. Therefore move it there. Signed-off-by: Bert Wesarg <bert.wesarg@googlemail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* Merge branch 'jc/conflict-marker-size'Junio C Hamano2010-01-20
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * jc/conflict-marker-size: rerere: honor conflict-marker-size attribute rerere: prepare for customizable conflict marker length conflict-marker-size: new attribute rerere: use ll_merge() instead of using xdl_merge() merge-tree: use ll_merge() not xdl_merge() xdl_merge(): allow passing down marker_size in xmparam_t xdl_merge(): introduce xmparam_t for merge specific parameters git_attr(): fix function signature Conflicts: builtin-merge-file.c ll-merge.c xdiff/xdiff.h xdiff/xmerge.c
| * xdl_merge(): allow passing down marker_size in xmparam_tJunio C Hamano2010-01-16
| | | | | | | | | | | | | | This allows the callers of xdl_merge() to pass marker_size (defaults to 7) in xmparam_t argument, to use conflict markers of non-default length. Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xdl_merge(): introduce xmparam_t for merge specific parametersJunio C Hamano2010-01-16
| | | | | | | | | | | | | | | | So far we have only needed to be able to pass an option that is generic to xdiff family of functions to this function. Extend the interface so that we can give it merge specific parameters. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | git-merge-file --ours, --theirsJunio C Hamano2009-11-29
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sometimes people want their conflicting merges autoresolved by favouring upstream changes. The standard answer they are given is to run "git diff --name-only | xargs git checkout MERGE_HEAD --" in such a case. This is to accept automerge results for the paths that are fully resolved automatically, while taking their version of the file in full for paths that have conflicts. This is problematic on two counts. One is that this is not exactly what these people want. It discards all changes they did on their branch for any paths that conflicted. They usually want to salvage as much automerge result as possible in a conflicted file, and want to take the upstream change only in the conflicted part. This patch teaches two new modes of operation to the lowest-lever merge machinery, xdl_merge(). Instead of leaving the conflicted lines from both sides enclosed in <<<, ===, and >>> markers, the conflicts are resolved favouring our side or their side of changes. A larger problem is that this tends to encourage a bad workflow by allowing people to record such a mixed up half-merged result as a full commit without auditing. This commit does not tackle this issue at all. In git, we usually give long enough rope to users with strange wishes as long as the risky features are not enabled by default, and this is such a risky feature. Signed-off-by: Avery Pennarun <apenwarr@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* Merge branch 'tf/diff-whitespace-incomplete-line'Junio C Hamano2009-08-31
|\ | | | | | | | | | | * tf/diff-whitespace-incomplete-line: xutils: Fix xdl_recmatch() on incomplete lines xutils: Fix hashing an incomplete line with whitespaces at the end
| * xutils: Fix xdl_recmatch() on incomplete linesJunio C Hamano2009-08-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Thell Fowler noticed that various "ignore whitespace" options to git diff do not work well on an incomplete line. The loop control of the function responsible for these bugs was extremely difficult to follow. This patch restructures the loops for three variants of "ignore whitespace" logic. The basic idea of the re-written logic is: - A loop runs while the characters from both strings we are looking at match. We declare unmatch immediately when we find something that does not match and return false from the function. We break out of the loop if we ran out of either side of the string. The way we skip spaces inside this loop varies depending on the style of ignoring whitespaces. - After the above loop breaks, we know that the parts of the strings we inspected so far match, ignoring the whitespaces. The lines can match only if the remainder consists of nothing but whitespaces. This part of the logic is shared across all three styles. The new code is more obvious and should be much easier to follow. Tested-by: Thell Fowler <git@tbfowler.name> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * xutils: Fix hashing an incomplete line with whitespaces at the endJunio C Hamano2009-08-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Upon seeing a whitespace, xdl_hash_record_with_whitespace() first skipped the run of whitespaces (excluding LF) that begins there, ensuring that the pointer points at the last whitespace character in the run, and assumed that the next character must be LF at the end of the line. This does not work when hashing an incomplete line, which lacks the LF at the end. Introduce "at_eol" variable that is true when either we are at the end of line (looking at LF) or at the end of an incomplete line, and use that instead throughout the code. Noticed by Thell Fowler. Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * Merge branch 'kc/maint-diff-bwi-fix' into maintJunio C Hamano2009-02-05
| |\ | | | | | | | | | | | | | | | * kc/maint-diff-bwi-fix: Fix combined use of whitespace ignore options to diff test more combinations of ignore-whitespace options to diff
* | | refactor: use bitsizeof() instead of 8 * sizeof()Pierre Habouzit2009-07-22
| | | | | | | | | | | | | | | Signed-off-by: Pierre Habouzit <madcoder@debian.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | Merge branch 'cb/maint-1.6.0-xdl-merge-fix' into maintJunio C Hamano2009-06-02
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * cb/maint-1.6.0-xdl-merge-fix: Change xdl_merge to generate output even for null merges t6023: merge-file fails to output anything for a degenerate merge Conflicts: xdiff/xmerge.c
| * | | Change xdl_merge to generate output even for null mergesCharles Bailey2009-05-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | xdl_merge used to have a check to ensure that there was at least some change in one or other side being merged but this suppressed output for the degenerate case when base, local and remote contents were all identical. Removing this check enables correct output in the degenerate case and xdl_free_script handles freeing NULL scripts so there is no need to have the check for these calls. Signed-off-by: Charles Bailey <charles@hashpling.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | Fix typos / spelling in commentsMike Ralphson2009-04-22
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Mike Ralphson <mike@abacus.co.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | Fix various dead stores found by the clang static analyzerBenjamin Kramer2009-03-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | http-push.c::finish_request(): request is initialized by the for loop index-pack.c::free_base_data(): b is initialized by the for loop merge-recursive.c::process_renames(): move compare to narrower scope, and remove unused assignments to it remove unused variable renames2 xdiff/xdiffi.c::xdl_recs_cmp(): remove unused variable ec xdiff/xemit.c::xdl_emit_diff(): xche is always overwritten Signed-off-by: Benjamin Kramer <benny.kra@googlemail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | Merge branch 'js/patience-diff'Junio C Hamano2009-01-23
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * js/patience-diff: bash completions: Add the --patience option Introduce the diff option '--patience' Implement the patience diff algorithm Conflicts: contrib/completion/git-completion.bash
| * | | | Implement the patience diff algorithmJohannes Schindelin2009-01-07
| | |/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The patience diff algorithm produces slightly more intuitive output than the classic Myers algorithm, as it does not try to minimize the number of +/- lines first, but tries to preserve the lines that are unique. To this end, it first determines lines that are unique in both files, then the maximal sequence which preserves the order (relative to both files) is extracted. Starting from this initial set of common lines, the rest of the lines is handled recursively, with Myers' algorithm as a fallback when the patience algorithm fails (due to no common unique lines). This patch includes memory leak fixes by Pierre Habouzit. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | Merge branch 'kc/maint-diff-bwi-fix'Junio C Hamano2009-01-21
|\ \ \ \ | | |_|/ | |/| | | | | | | | | | * kc/maint-diff-bwi-fix: Fix combined use of whitespace ignore options to diff
| * | | Fix combined use of whitespace ignore options to diffKeith Cascio2009-01-19
| | |/ | |/| | | | | | | | | | | | | | | | | | | The code used to misbehave when options to ignore certain whitespaces (-w -b and --ignore-at-eol) were combined. Signed-off-by: Keith Cascio <keith@cs.ucla.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * | xdiff: give up scanning similar lines earlyDavide Libenzi2008-12-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | In a corner case of large files whose lines do not match uniquely, the loop to eliminate a line that matches multiple locations adjacent to a run of lines that do not uniquely match wasted too much cycles. Fix this by giving up early after scanning 100 lines in both direction. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | diff: add option to show context between close hunksRené Scharfe2008-12-29
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge two hunks if there is only the specified number of otherwise unshown context between them. For --inter-hunk-context=1, the resulting patch has the same number of lines but shows uninterrupted context instead of a context header line in between. Patches generated with this option are easier to read but are also more likely to conflict if the file to be patched contains other changes. This patch keeps the default for this option at 0. It is intended to just make the feature available in order to see its advantages and downsides. Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | Merge branch 'dl/xdiff'Junio C Hamano2008-11-12
|\ \ | | | | | | | | | | | | * dl/xdiff: xdiff: give up scanning similar lines early
| * | xdiff: give up scanning similar lines earlyDavide Libenzi2008-11-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | In a corner case of large files whose lines do not match uniquely, the loop to eliminate a line that matches multiple locations adjacent to a run of lines that do not uniquely match wasted too much cycles. Fix this by giving up early after scanning 100 lines in both direction. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | Allow alternate "low-level" emit function from xdl_diffBrian Downing2008-10-25
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For some users (e.g. git blame), getting textual patch output is just extra work, as they can get all the information they need from the low- level diff structures. Allow for an alternate low-level emit function to be defined to allow bypassing the textual patch generation; set xemitconf_t's emit_func member to enable this. The (void (*)()) type is pretty ugly, but the alternative would be to include most of the private xdiff headers in xdiff.h to get the types required for the "proper" function prototype. Also, a (void *) won't work, as ANSI C doesn't allow a function pointer to be cast to an object pointer. Signed-off-by: Brian Downing <bdowning@lavos.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | xmerge.c: "diff3 -m" style clips merge reduction level to EAGER or lessJunio C Hamano2008-08-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When showing a conflicting merge result, and "--diff3 -m" style is asked for, this patch makes sure that the merge reduction level does not exceed XDL_MERGE_EAGER. This is because "diff3 -m" style output would not make sense for anything more aggressive than XDL_MERGE_EAGER, because of the way how the merge reduction works. "git merge-file" no longer has to force MERGE_EAGER when "--diff3" is asked for because of this change. Suppose a common ancestor (shared preimage) is modified to postimage #1 and #2 (each letter represents one line): ##### postimage#1: 1234ABCDE789 | / | / preimage: 123456789 | \ postimage#2: 1234AXYE789 #### XDL_MERGE_MINIMAL and XDL_MERGE_EAGER would: (1) find the s/56/ABCDE/ done on one side and s/56/AXYE/ done on the other side, (2) notice that they touch an overlapping area, and (3) mark it as a conflict, "ABCDE vs AXYE". The difference between the two algorithms is that EAGER drops the hunk altogether if the postimages match (i.e. both sides modified the same way), while MINIMAL keeps it. There is no other operation performed to the hunk. As the result, lines marked with "#" in the above picure will be in the RCS merge style output like this (letters <, = and > represent conflict marker lines): output: 1234<ABCDE=AXYE>789 ; with MINIMAL/EAGER The part from the preimage that corresponds to these conflicting changes is "56", which is what "diff3 -m" style output adds to it: output: 1234<ABCDE|56=AXYE>789 ; in "diff3 -m" style Now, XDL_MERGE_ZEALOUS looks at the differences between the changes two postimages made in order to reduce the number of lines in the conflicting regions. It notices that both sides start their new contents with "A", and excludes it from the output (it also excludes "E" for the same reason). The conflict that used to be "ABCDE vs AXYE" is now "BCD vs XY": output: 1234A<BCD=XY>E789 ; with ZEALOUS There could even be matching parts between two postimages in the middle. Instead of one side rewriting the shared "56" to "ABCDE" and the other side to "AXYE", imagine the case where the postimages are "ABCDE" and "AXCYE", in which case instead of having one conflicted hunk "BCD vs XY", you would have two conflicting hunks "B vs X" and "D vs Y". In either case, once you reduce "ABCDE vs AXYE" to "BCD vs XY" (or "ABCDE vs AXCYE" to "B vs X" and "D vs Y"), there is no part from the preimage that corresponds to the conflicting change made in both postimages anymore. In other words, conflict reduced by ZEALOUS algorithm cannot be expressed in "diff3 -m" style. Representing the last illustration like this is misleading to say the least: output: 1234A<BCD|56=XY>E789 ; broken "diff3 -m" style because the preimage was not ...4A56E... to begin with. "A" and "E" are common only between the postimages. Even worse, once a single conflicting hunk is split into multiple ones (recall the example of breaking "ABCDE vs AXCYE" to "B vs X" and "D vs Y"), there is no sane way to distribute the preimage text across split conflicting hunks. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | xmerge.c: minimum readability fixupsJunio C Hamano2008-08-30
| | | | | | | | | | | | | | | | This replaces hardcoded magic constants with symbolic ones for readability, and swaps one if/else blocks to better match the order in which 0/1/2 variables are handled to nearby codepath. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | xdiff-merge: optionally show conflicts in "diff3 -m" styleJunio C Hamano2008-08-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When showing conflicting merges, we traditionally followed RCS's merge output format. The output shows: <<<<<<< postimage from one side; ======= postimage of the other side; and >>>>>>> Some poeple find it easier to be able to understand what is going on when they can view the common ancestor's version, which is used by "diff3 -m", which shows: <<<<<<< postimage from one side; ||||||| shared preimage; ======= postimage of the other side; and >>>>>>> This is an initial step to bring that as an optional feature to git. Only "git merge-file" has been converted, with "--diff3" option. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | xdl_fill_merge_buffer(): separate out a too deeply nested functionJunio C Hamano2008-08-30
|/ | | | | | | This simply moves code around to make a separate function that prepares a single conflicted hunk with markers into the buffer. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* xdl_merge(): introduce XDL_MERGE_ZEALOUS_ALNUMJohannes Schindelin2008-02-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a merge conflicts, there are often common lines that are not really common, such as empty lines or lines containing a single curly bracket. With XDL_MERGE_ZEALOUS_ALNUM, we use the following heuristics: when a hunk does not contain any letters or digits, it is treated as conflicting. In other words, a conflict which used to look like this: <<<<<<< a = 1; ======= output(); >>>>>>> } } } <<<<<<< output(); ======= b = 1; >>>>>>> will look like this with ZEALOUS_ALNUM: <<<<<<< a = 1; } } } output(); ======= output(); } } } b = 1; >>>>>>> To demonstrate this, git-merge-file has been switched from XDL_MERGE_ZEALOUS to XDL_MERGE_ZEALOUS_ALNUM. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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