kernel/git - git - PowerEL Git System

Author	SHA1	Message	Date
Johannes Schindelin	ee95ec5d58	xdl_merge(): introduce XDL_MERGE_ZEALOUS_ALNUM 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>	17 years ago
Johannes Schindelin	f407f14dea	xdl_merge(): make XDL_MERGE_ZEALOUS output simpler When a merge conflicts, there are often less than three common lines between two conflicting regions. Since a conflict takes up as many lines as are conflicting, plus three lines for the commit markers, the output will be shorter (and thus, simpler) in this case, if the common lines will be merged into the conflicting regions. This patch merges up to three common lines into the conflicts. For example, what looked like this before this patch: <<<<<<< if (a == 1) ======= if (a != 0) >>>>>>> { int i; <<<<<<< a = 0; ======= a = !a; >>>>>>> will now look like this: <<<<<<< if (a == 1) { int i; a = 0; ======= if (a != 0) { int i; a = !a; >>>>>>> Suggested Linus (based on ideas by "Voltage Spike" -- if that name is real, it is mighty cool). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>	17 years ago
Johannes Schindelin	22b6abcd08	Fix yet another subtle xdl_merge() bug In very obscure cases, a merge can hit an unexpected code path (where the original code went as far as saying that this was a bug). This failing merge was noticed by Alexandre Juillard. The problem is that the original file contains something like this: -- snip -- two non-empty lines before two empty lines after two empty lines -- snap -- and this snippet is reduced to _one_ empty line in _both_ new files. However, it is ambiguous as to which hunk takes the empty line: the first or the second one? Indeed in Alexandre's example files, the xdiff algorithm attributes the empty line to the first hunk in one case, and to the second hunk in the other case. (Trimming down the example files _changes_ that behaviour!) Thus, the call to xdl_merge_cmp_lines() has no chance to realize that the change is actually identical in both new files. Therefore, xdl_refine_conflicts() finds an empty diff script, which was not expected there, because (the original author of xdl_merge() thought) xdl_merge_cmp_lines() would catch that case earlier. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>	18 years ago
Johannes Schindelin	5d6b151fdd	xdl_merge(): fix a segmentation fault when refining conflicts The function xdl_refine_conflicts() tries to break down huge conflicts by doing a diff on the conflicting regions. However, this does not make sense when one side is empty. Worse, when one side is not only empty, but after EOF, the code accessed unmapped memory. Noticed by Luben Tuikov, Shawn Pearce and Alexandre Julliard, the latter providing a test case. Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>	18 years ago
Johannes Schindelin	98e6da8a36	xdl_merge(): fix and simplify conflict handling Suppose you have changes in new1 to the original lines 10-20, and changes in new2 to the original lines 15-25, then the changes to 10-25 conflict. But it is possible that the next changes in new1 still overlap with this change to new2. So, in the next iteration we have to look at the same change to new2 again. The old code tried to be a bit too clever. The new code is shorter and more to the point: do not fiddle with the ranges at all. Also, xdl_append_merge() tries harder to combine conflicts. This is necessary, because with the above simplification, some conflicts would not be recognized as conflicts otherwise: In the above scenario, it is possible that there is no other change to new1. Absent the combine logic, the change in new2 would be recorded _again_, but as a non-conflict. Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>	18 years ago
Johannes Schindelin	710daa83fc	xdl_merge(): fix thinko If one side's block (of changed lines) ends later than the other side's block, the former should be tested against the next block of the other side, not vice versa. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>	18 years ago
Johannes Schindelin	875b8ce476	xdl_merge(): fix an off-by-one bug The line range is i1 .. (i1 + chg1 - 1), not i1 .. (i1 + chg1). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>	18 years ago
Junio C Hamano	53a7085a10	xmerge: make return value from xdl_merge() more usable. The callers would want to know if the resulting merge is clean; do not discard that information away after calling xdl_do_merge(). Signed-off-by: Junio C Hamano <junkio@cox.net>	18 years ago
Johannes Schindelin	857b933e04	xdiff: add xdl_merge() This new function implements the functionality of RCS merge, but in-memory. It returns < 0 on error, otherwise the number of conflicts. Finding the conflicting lines can be a very expensive task. You can control the eagerness of this algorithm: - a level value of 0 means that all overlapping changes are treated as conflicts, - a value of 1 means that if the overlapping changes are identical, it is not treated as a conflict. - If you set level to 2, overlapping changes will be analyzed, so that almost identical changes will not result in huge conflicts. Rather, only the conflicting lines will be shown inside conflict markers. With each increasing level, the algorithm gets slower, but more accurate. Note that the code for level 2 depends on the simple definition of mmfile_t specific to git, and therefore it will be harder to port that to LibXDiff. Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>	18 years ago