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2005-05-24[PATCH] Redo rename/copy detection logic.Junio C Hamano
Earlier implementation had a major screw-up in the memory management area. Rename/copy logic sometimes borrowed a pointer to a structure without any provision for downstream to determine which pointer is shared and which is not. This resulted in the later clean-up code to sometimes double free such structure, resulting in a segfault. This made -M and -C useless. Another problem the earlier implementation had was that it reordered the patches, and forced the logic to differentiate renames and copies to depend on that particular order. This problem was fixed by teaching rename/copy detection logic not to do any reordering, and rename-copy differentiator not to depend on the order of the patches. The diffs will leave rename/copy detector in the same destination path order as the patch that was fed into it. Some test vectors have been reordered to accommodate this change. It also adds a sanity check logic to the human-readable diff-raw output to detect paths with embedded TAB and LF characters, which cannot be expressed with that format. This idea came up during a discussion with Chris Wedgwood. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-24[PATCH] Fix diff-pruning logic which was running prune too early.Junio C Hamano
For later stages to reorder patches, pruning logic and rename detection logic should not decide which delete to discard (because another entry said it will take over the file as a rename) until the very end. Also fix some tests that were assuming the earlier "last one is rename or keep everything else is copy" semantics of diff-raw format, which no longer is true. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-23[PATCH] Rename/copy detection fix.Junio C Hamano
The rename/copy detection logic in earlier round was only good enough to show patch output and discussion on the mailing list about the diff-raw format updates revealed many problems with it. This patch fixes all the ones known to me, without making things I want to do later impossible, mostly related to patch reordering. (1) Earlier rename/copy detector determined which one is rename and which one is copy too early, which made it impossible to later introduce diffcore transformers to reorder patches. This patch fixes it by moving that logic to the very end of the processing. (2) Earlier output routine diff_flush() was pruning all the "no-change" entries indiscriminatingly. This was done due to my false assumption that one of the requirements in the diff-raw output was not to show such an entry (which resulted in my incorrect comment about "diff-helper never being able to be equivalent to built-in diff driver"). My special thanks go to Linus for correcting me about this. When we produce diff-raw output, for the downstream to be able to tell renames from copies, sometimes it _is_ necessary to output "no-change" entries, and this patch adds diffcore_prune() function for doing it. (3) Earlier diff_filepair structure was trying to be not too specific about rename/copy operations, but the purpose of the structure was to record one or two paths, which _was_ indeed about rename/copy. This patch discards xfrm_msg field which was trying to be generic for this wrong reason, and introduces a couple of fields (rename_score and rename_rank) that are explicitly specific to rename/copy logic. One thing to note is that the information in a single diff_filepair structure _still_ does not distinguish renames from copies, and it is deliberately so. This is to allow patches to be reordered in later stages. (4) This patch also adds some tests about diff-raw format output and makes sure that necessary "no-change" entries appear on the output. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-23[PATCH] Be careful with symlinks when detecting renames and copies.Junio C Hamano
Earlier round was not treating symbolic links carefully enough, and would have produced diff output that renamed/copied then edited the contents of a symbolic link, which made no practical sense. Change it to detect only pure renames. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-22[PATCH] Diffcore updates.Junio C Hamano
This moves the path selection logic from individual programs to a new diffcore transformer (diff-tree still needs to have its own for performance reasons). Also the header printing code in diff-tree was tweaked not to produce anything when pickaxe is in effect and there is nothing interesting to report. An interesting example is the following in the GIT archive itself: $ git-whatchanged -p -C -S'or something in a real script' Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-22[PATCH] Add the code to set default minimum score back in.Junio C Hamano
When the minimum score is specified as 0 (meaning "use default value"), set it to the default as we are told. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-22[PATCH] Fix tweak in similarity estimator.Junio C Hamano
There was a screwy math bug in the estimator that confused what -C1 meant and what -C9 meant, only in one of the early "cheap" check, which resulted in quite confusing behaviour. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-22[PATCH] The diff-raw format updates.Junio C Hamano
Update the diff-raw format as Linus and I discussed, except that it does not use sequence of underscore '_' letters to express nonexistence. All '0' mode is used for that purpose instead. The new diff-raw format can express rename/copy, and the earlier restriction that -M and -C _must_ be used with the patch format output is no longer necessary. The patch makes -M and -C flags independent of -p flag, so you need to say git-whatchanged -M -p to get the diff/patch format. Updated are both documentations and tests. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-22[PATCH] Prepare diffcore interface for diff-tree header supression.Junio C Hamano
This does not actually supress the extra headers when pickaxe is used, but prepares enough support for diff-tree to implement it. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-21[PATCH] Tweak diffcore-rename heuristics.Junio C Hamano
The heuristics so far was to compare file size change and xdelta size against the average of file size before and after the change. This patch uses the smaller of pre- and post- change file size instead. It also makes a very small performance fix. I didn't measure it; I do not expect it to make any practical difference, but while scanning an already sorted list, breaking out in the middle is the right thing. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-21[PATCH] Introducing software archaeologist's tool "pickaxe".Junio C Hamano
This steals the "pickaxe" feature from JIT and make it available to the bare Plumbing layer. From the command line, the user gives a string he is intersted in. Using the diff-core infrastructure previously introduced, it filters the differences to limit the output only to the diffs between <src> and <dst> where the string appears only in one but not in the other. For example: $ ./git-rev-list HEAD | ./git-diff-tree -Sdiff-tree-helper --stdin -M would show the diffs that touch the string "diff-tree-helper". In real software-archaeologist application, you would typically look for a few to several lines of code and see where that code came from. The "pickaxe" module runs after "rename/copy detection" module, so it even crosses the file rename boundary, as the above example demonstrates. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-21[PATCH] Diff overhaul, adding half of copy detection.Junio C Hamano
This introduces the diff-core, the layer between the diff-tree family and the external diff interface engine. The calls to the interface diff-tree family uses (diff_change and diff_addremove) have not changed and will not change. The purpose of the diff-core layer is to provide an infrastructure to transform the set of differences sent from the applications, before sending them to the external diff interface. The recently introduced rename detection code has been rewritten to use the diff-core facility. When applications send in separate creates and deletes, matching ones are transformed into a single rename-and-edit diff, and sent out to the external diff interface as such. This patch also enhances the rename detection code further to be able to detect copies. Currently this happens only as long as copy sources appear as part of the modified files, but there already is enough provision for callers to report unmodified files to diff-core, so that they can be also used as copy source candidates. Extending the callers this way will be done in a separate patch. Please see and marvel at how well this works by trying out the newly added t/t4003-diff-rename-1.sh test script. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>