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Diffstat (limited to 'Documentation/diff-format.txt')
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diff --git a/Documentation/diff-format.txt b/Documentation/diff-format.txt new file mode 100644 index 0000000000..9298d79e51 --- /dev/null +++ b/Documentation/diff-format.txt @@ -0,0 +1,135 @@ +The output format from "git-diff-cache", "git-diff-tree" and +"git-diff-files" is very similar. + +These commands all compare two sets of things; what are +compared are different: + +git-diff-cache <tree-ish>:: + compares the <tree-ish> and the files on the filesystem. + +git-diff-cache --cached <tree-ish>:: + compares the <tree-ish> and the cache. + +git-diff-tree [-r] <tree-ish-1> <tree-ish-2> [<pattern>...]:: + compares the trees named by the two arguments. + +git-diff-files [<pattern>...]:: + compares the cache and the files on the filesystem. + + +An output line is formatted this way: + +in-place edit :100644 100644 bcd1234... 0123456... M file0 +copy-edit :100644 100644 abcd123... 1234567... C68 file1 file2 +rename-edit :100644 100644 abcd123... 1234567... R86 file1 file3 +create :000000 100644 0000000... 1234567... N file4 +delete :100644 000000 1234567... 0000000... D file5 +unmerged :000000 000000 0000000... 0000000... U file6 + +That is, from the left to the right: + + (1) a colon. + (2) mode for "src"; 000000 if creation or unmerged. + (3) a space. + (4) mode for "dst"; 000000 if deletion or unmerged. + (5) a space. + (6) sha1 for "src"; 0{40} if creation or unmerged. + (7) a space. + (8) sha1 for "dst"; 0{40} if creation, unmerged or "look at work tree". + (9) a space. + (10) status, followed by optional "score" number. + (11) a tab or a NUL when '-z' option is used. + (12) path for "src" + (13) a tab or a NUL when '-z' option is used; only exists for C or R. + (14) path for "dst"; only exists for C or R. + (15) an LF or a NUL when '-z' option is used, to terminate the record. + +<sha1> is shown as all 0's if new is a file on the filesystem +and it is out of sync with the cache. Example: + + :100644 100644 5be4a4...... 000000...... M file.c + +Generating patches with -p +-------------------------- + +When "git-diff-cache", "git-diff-tree", or "git-diff-files" are run +with a '-p' option, they do not produce the output described above; +instead they produce a patch file. + +The patch generation can be customized at two levels. This +customization also applies to "git-diff-helper". + +1. When the environment variable 'GIT_EXTERNAL_DIFF' is not set, + these commands internally invoke "diff" like this: + + diff -L a/<path> -L b/<path> -pu <old> <new> ++ +For added files, `/dev/null` is used for <old>. For removed +files, `/dev/null` is used for <new> ++ +The "diff" formatting options can be customized via the +environment variable 'GIT_DIFF_OPTS'. For example, if you +prefer context diff: + + GIT_DIFF_OPTS=-c git-diff-cache -p $(cat .git/HEAD) + + +2. When the environment variable 'GIT_EXTERNAL_DIFF' is set, the + program named by it is called, instead of the diff invocation + described above. ++ +For a path that is added, removed, or modified, +'GIT_EXTERNAL_DIFF' is called with 7 parameters: + + path old-file old-hex old-mode new-file new-hex new-mode ++ +where: + + <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the + contents of <old|ne>, + <old|new>-hex:: are the 40-hexdigit SHA1 hashes, + <old|new>-mode:: are the octal representation of the file modes. + ++ +The file parameters can point at the user's working file +(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file` +when a new file is added), or a temporary file (e.g. `old-file` in the +cache). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the +temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits. + +For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1 +parameter, <path>. + + +Git specific extension to diff format +------------------------------------- + +What -p option produces is slightly different from the +traditional diff format. + + (1) It is preceeded with a "git diff" header, that looks like + this: + + diff --git a/file1 b/file2 + + The a/ and b/ filenames are the same unless rename/copy is + involved. Especially, even for a creation or a deletion, + /dev/null is _not_ used in place of a/ or b/ filename. + + When rename/copy is involved, file1 and file2 shows the + name of the source file of the rename/copy and the name of + the file that rename/copy produces, respectively. + + (2) It is followed by extended header lines that are one or + more of: + + old mode <mode> + new mode <mode> + deleted file mode <mode> + new file mode <mode> + copy from <path> + copy to <path> + rename from <path> + rename to <path> + similarity index <number> + dissimilarity index <number> |