Introduction
------------
-The diff commands git-diff-cache, git-diff-files, and
+The diff commands git-diff-index, git-diff-files, and
git-diff-tree can be told to manipulate differences they find
in unconventional ways before showing diff(1) output. The
manipulation is collectively called "diffcore transformation".
The git-diff-* family works by first comparing two sets of
files:
- - git-diff-cache compares contents of a "tree" object and the
- working directory (when --cached flag is not used) or a
- "tree" object and the index file (when --cached flag is
+ - git-diff-index compares contents of a "tree" object and the
+ working directory (when '\--cached' flag is not used) or a
+ "tree" object and the index file (when '\--cached' flag is
used);
- git-diff-files compares contents of the index file and the
called "diffcore", in a format similar to what is output when
the -p option is not used. E.g.
- in-place edit :100644 100644 bcd1234... 0123456... M file0
- create :000000 100644 0000000... 1234567... N file4
- delete :100644 000000 1234567... 0000000... D file5
- unmerged :000000 000000 0000000... 0000000... U file6
+------------------------------------------------
+in-place edit :100644 100644 bcd1234... 0123456... M file0
+create :000000 100644 0000000... 1234567... A file4
+delete :100644 000000 1234567... 0000000... D file5
+unmerged :000000 000000 0000000... 0000000... U file6
+------------------------------------------------
The diffcore mechanism is fed a list of such comparison results
(each of which is called "filepair", although at this point each
of them talks about a single file), and transforms such a list
into another list. There are currently 6 such transformations:
- - diffcore-pathspec
- - diffcore-break
- - diffcore-rename
- - diffcore-merge-broken
- - diffcore-pickaxe
- - diffcore-order
+- diffcore-pathspec
+- diffcore-break
+- diffcore-rename
+- diffcore-merge-broken
+- diffcore-pickaxe
+- diffcore-order
-These are applied in sequence. The set of filepairs git-diff-*
+These are applied in sequence. The set of filepairs git-diff-\*
commands find are used as the input to diffcore-pathspec, and
the output from diffcore-pathspec is used as the input to the
next transformation. The final result is then passed to the
output routine and generates either diff-raw format (see Output
-format sections of the manual for git-diff-* commands) or
+format sections of the manual for git-diff-\* commands) or
diff-patch format.
break such filepair into two filepairs that represent delete and
create. E.g. If the input contained this filepair:
- :100644 100644 bcd1234... 0123456... M file0
+------------------------------------------------
+:100644 100644 bcd1234... 0123456... M file0
+------------------------------------------------
and if it detects that the file "file0" is completely rewritten,
it changes it to:
- :100644 000000 bcd1234... 0000000... D file0
- :000000 100644 0000000... 0123456... N file0
+------------------------------------------------
+:100644 000000 bcd1234... 0000000... D file0
+:000000 100644 0000000... 0123456... A file0
+------------------------------------------------
For the purpose of breaking a filepair, diffcore-break examines
the extent of changes between the contents of the files before
(to detect copies as well) to the git-diff-* commands. If the
input contained these filepairs:
- :100644 000000 0123456... 0000000... D fileX
- :000000 100644 0000000... 0123456... N file0
+------------------------------------------------
+:100644 000000 0123456... 0000000... D fileX
+:000000 100644 0000000... 0123456... A file0
+------------------------------------------------
and the contents of the deleted file fileX is similar enough to
the contents of the created file file0, then rename detection
merges these filepairs and creates:
- :100644 100644 0123456... 0123456... R100 fileX file0
+------------------------------------------------
+:100644 100644 0123456... 0123456... R100 fileX file0
+------------------------------------------------
When the "-C" option is used, the original contents of modified
files and contents of unchanged files are considered as
filepairs, that talk about a modified file fileY and a newly
created file file0:
- :100644 100644 0123456... 1234567... M fileY
- :000000 100644 0000000... 0123456... N file0
+------------------------------------------------
+:100644 100644 0123456... 1234567... M fileY
+:000000 100644 0000000... 0123456... A file0
+------------------------------------------------
the original contents of fileY and the resulting contents of
file0 are compared, and if they are similar enough, they are
changed to:
- :100644 100644 0123456... 1234567... M fileY
- :100644 100644 0123456... 0123456... C100 fileY file0
+------------------------------------------------
+:100644 100644 0123456... 1234567... M fileY
+:100644 100644 0123456... 0123456... C100 fileY file0
+------------------------------------------------
In both rename and copy detection, the same "extent of changes"
algorithm used in diffcore-break is used to determine if two
number after "-M" or "-C" option (e.g. "-M8" to tell it to use
8/10 = 80%).
-Note. When the "-C" option is used with --find-copies-harder
-option, git-diff-* commands feed unmodified filepairs to
+Note. When the "-C" option is used with `\--find-copies-harder`
+option, git-diff-\* commands feed unmodified filepairs to
diffcore mechanism as well as modified ones. This lets the copy
detector consider unmodified files as copy source candidates at
-the expense of making it slower. Without --find-copies-harder,
-git-diff-* commands can detect copies only if the file that was
+the expense of making it slower. Without `\--find-copies-harder`,
+git-diff-\* commands can detect copies only if the file that was
copied happened to have been modified in the same changeset.
single modification) by giving a second number to -B option,
like these:
- -B50/60 (give 50% "break score" to diffcore-break, use
- 60% for diffcore-merge-broken).
- -B/60 (the same as above, since diffcore-break defautls to
- 50%).
+* -B50/60 (give 50% "break score" to diffcore-break, use 60%
+ for diffcore-merge-broken).
+
+* -B/60 (the same as above, since diffcore-break defaults to 50%).
Note that earlier implementation left a broken pair as a separate
creation and deletion patches. This was unnecessary hack and
This transformation is used to find filepairs that represent
changes that touch a specified string, and is controlled by the
--S option and the --pickaxe-all option to the git-diff-*
+-S option and the `\--pickaxe-all` option to the git-diff-*
commands.
When diffcore-pickaxe is in use, it checks if there are
string appeared in this changeset". It also checks for the
opposite case that loses the specified string.
-When --pickaxe-all is not in effect, diffcore-pickaxe leaves
+When `\--pickaxe-all` is not in effect, diffcore-pickaxe leaves
only such filepairs that touches the specified string in its
-output. When --pickaxe-all is used, diffcore-pickaxe leaves all
+output. When `\--pickaxe-all` is used, diffcore-pickaxe leaves all
filepairs intact if there is such a filepair, or makes the
output empty otherwise. The latter behaviour is designed to
make reviewing of the changes in the context of the whole
filepairs that do not match any glob pattern are output last.
As an example, typical orderfile for the core GIT probably
-should look like this:
-
- README
- Makefile
- Documentation
- *.h
- *.c
- t
+would look like this:
+
+------------------------------------------------
+README
+Makefile
+Documentation
+*.h
+*.c
+t
+------------------------------------------------