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authorc.shoemaker@cox.net <c.shoemaker@cox.net>2005-10-29 04:15:49 (GMT)
committerJunio C Hamano <junkio@cox.net>2005-10-29 05:21:35 (GMT)
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Minor clarifications in diffcore documentation
Signed-off-by: Chris Shoemaker <c.shoemaker at cox.net> Signed-off-by: Junio C Hamano <junkio@cox.net>
Diffstat (limited to 'Documentation/diffcore.txt')
-rw-r--r--Documentation/diffcore.txt65
1 files changed, 38 insertions, 27 deletions
diff --git a/Documentation/diffcore.txt b/Documentation/diffcore.txt
index 7c2168a..c9134de 100644
--- a/Documentation/diffcore.txt
+++ b/Documentation/diffcore.txt
@@ -6,13 +6,12 @@ June 2005
Introduction
------------
-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".
-This short note describes what they are and how to use them to
-produce diff outputs that are easier to understand than the
-conventional kind.
+The diff commands git-diff-index, git-diff-files, git-diff-tree, and
+git-diff-stages can be told to manipulate differences they find in
+unconventional ways before showing diff(1) output. The manipulation
+is collectively called "diffcore transformation". This short note
+describes what they are and how to use them to produce diff outputs
+that are easier to understand than the conventional kind.
The chain of operation
@@ -29,7 +28,10 @@ files:
- git-diff-files compares contents of the index file and the
working directory;
- - git-diff-tree compares contents of two "tree" objects.
+ - git-diff-tree compares contents of two "tree" objects;
+
+ - git-diff-stages compares contents of blobs at two stages in an
+ unmerged index file.
In all of these cases, the commands themselves compare
corresponding paths in the two sets of files. The result of
@@ -65,14 +67,23 @@ format sections of the manual for git-diff-\* commands) or
diff-patch format.
-diffcore-pathspec
+diffcore-pathspec: For Ignoring Files Outside Our Consideration
-----------------
The first transformation in the chain is diffcore-pathspec, and
is controlled by giving the pathname parameters to the
git-diff-* commands on the command line. The pathspec is used
to limit the world diff operates in. It removes the filepairs
-outside the specified set of pathnames.
+outside the specified set of pathnames. E.g. If the input set
+of filepairs included:
+
+------------------------------------------------
+:100644 100644 bcd1234... 0123456... M junkfile
+------------------------------------------------
+
+but the command invocation was "git-diff-files myfile", then the
+junkfile entry would be removed from the list because only "myfile"
+is under consideration.
Implementation note. For performance reasons, git-diff-tree
uses the pathname parameters on the command line to cull set of
@@ -80,7 +91,7 @@ filepairs it feeds the diffcore mechanism itself, and does not
use diffcore-pathspec, but the end result is the same.
-diffcore-break
+diffcore-break: For Splitting Up "Complete Rewrites"
--------------
The second transformation in the chain is diffcore-break, and is
@@ -115,7 +126,7 @@ the original is used), and can be customized by giving a number
after "-B" option (e.g. "-B75" to tell it to use 75%).
-diffcore-rename
+diffcore-rename: For Detection Renames and Copies
---------------
This transformation is used to detect renames and copies, and is
@@ -136,16 +147,16 @@ merges these filepairs and creates:
: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
-candidates of the source files in rename/copy operation, in
-addition to the deleted files. If the input were like these
-filepairs, that talk about a modified file fileY and a newly
+When the "-C" option is used, the original contents of modified files,
+and deleted files (and also unmodified files, if the
+"\--find-copies-harder" option is used) are considered as candidates
+of the source files in rename/copy operation. If the input were like
+these filepairs, that talk about a modified file fileY and a newly
created file file0:
------------------------------------------------
:100644 100644 0123456... 1234567... M fileY
-:000000 100644 0000000... 0123456... A file0
+:000000 100644 0000000... bcd3456... A file0
------------------------------------------------
the original contents of fileY and the resulting contents of
@@ -154,14 +165,14 @@ changed to:
------------------------------------------------
:100644 100644 0123456... 1234567... M fileY
-:100644 100644 0123456... 0123456... C100 fileY file0
+:100644 100644 0123456... bcd3456... 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
files are "similar enough", and can be customized to use
-similarity score different from the default 50% by giving a
-number after "-M" or "-C" option (e.g. "-M8" to tell it to use
+a similarity score different from the default of 50% by giving a
+number after the "-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`
@@ -173,7 +184,7 @@ git-diff-\* commands can detect copies only if the file that was
copied happened to have been modified in the same changeset.
-diffcore-merge-broken
+diffcore-merge-broken: For Putting "Complete Rewrites" Back Together
---------------------
This transformation is used to merge filepairs broken by
@@ -215,7 +226,7 @@ prefixed with '-', followed by the entire contents of new
version prefixed with '+'.
-diffcore-pickaxe
+diffcore-pickaxe: For Detecting Addition/Deletion of Specified String
----------------
This transformation is used to find filepairs that represent
@@ -230,7 +241,7 @@ 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
-only such filepairs that touches the specified string in its
+only such filepairs that touch the specified string in its
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
@@ -238,19 +249,19 @@ make reviewing of the changes in the context of the whole
changeset easier.
-diffcore-order
+diffcore-order: For Sorting the Output Based on Filenames
--------------
This is used to reorder the filepairs according to the user's
(or project's) taste, and is controlled by the -O option to the
git-diff-* commands.
-This takes a text file each of whose line is a shell glob
+This takes a text file each of whose lines is a shell glob
pattern. Filepairs that match a glob pattern on an earlier line
in the file are output before ones that match a later line, and
filepairs that do not match any glob pattern are output last.
-As an example, typical orderfile for the core git probably
+As an example, a typical orderfile for the core git probably
would look like this:
------------------------------------------------