Re: Meaning of double + and - in Gitk's diff pane
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Mar 21, 2011, 20:40 UTC
- Message-ID
- <7vwrjsnr5z.fsf@alter.siamese.dyndns.org>
- In-Reply-To
- <4D87AD9D.7080501@dirk.my1.cc>
Dirk Süsserott <newsletter@dirk.my1.cc> writes:
Show 10 quoted lines
> Am 21.03.2011 20:49 schrieb Junio C Hamano: >>> >>> Junio, thanks. When I've found the time, I'll probably condense Linus' >>> explanations and submit a documentation patch. It's not explained >>> in the actual git docs, right? >> >> How about checking "git diff"? The same conclusion should be in there, as >> I wrote the implementation, docs and the messages there. >> > Uhh, sorry, I missed that. That was actually what I was searching for.
Hmm... re-reading "git diff --help" and looking at the section on combined diff, I notice that we talk about how to understand its output, but we don't say under what rule the --cc option condenses what would be produced with the -c option. Perhaps we would need a patch after all at the end of Documentation/diff-generate-patch.txt file.
Here is a quick attempt.
Documentation/diff-generate-patch.txt | 18 ++++++++++++++++++ 1 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/Documentation/diff-generate-patch.txt b/Documentation/diff-generate-patch.txt index c57460c..20a603d 100644 --- a/Documentation/diff-generate-patch.txt +++ b/Documentation/diff-generate-patch.txt @@ -183,3 +183,21 @@ parents). When shown by `git diff-files -c`, it compares the two unresolved merge parents with the working tree file (i.e. file1 is stage 2 aka "our version", file2 is stage 3 aka "their version"). + +The "combined" format (`-c` option) shows the diff to the result (i.e. the +result of the merge, or the file in the working tree during a conflict +resolution) from two or more originals (i.e. parents of the merge or +branches being merged) combined, but it often shows many trivial changes +that the result takes the change from a single original verbatim. The +"dense combined" format (`--cc` option) removes such hunks with only +"trivial" changes. A hunk that has only two versions (or less) in the +original (in a usual two-parent merge, this always is the case, simply +because there are only two originals) and whose result matches exactly one +of the originals, is considered "trivial" and is omitted from the output +in the "dense combined" format. In the previous illustration of a +combined diff on `describe.c` file, there are two originals, one that had +the describe function with a single `char *arg` parameter, and the other +with two parameters, but the result matches neither of them, hence it is +not "trivial" and the hunk appears in the output. + +