git-commit-vandalism/Documentation/blame-options.txt
Jacob Keller 1a3119ed06 blame: allow --contents to work with non-HEAD commit
The --contents option can be used with git blame to blame the file as if
it had the contents from the specified file. This is akin to copying the
contents into the working tree and then running git blame. This option
has been supported since 1cfe77333f ("git-blame: no rev means start
from the working tree file.")

The --contents option always blames the file as if it was based on the
current HEAD commit. If you try to pass a revision while using
--contents, you get the following error:

  fatal: cannot use --contents with final commit object name

This is because the blame process generates a fake working tree commit
which always uses the HEAD object as its sole parent.

Enhance fake_working_tree_commit to take the object ID to use for the
parent instead of always using the HEAD object. Then, always generate a
fake commit when we have contents provided, even if we have a final
object. Remove the check to disallow --contents and a final revision.

Note that the behavior of generating a fake working commit is still
skipped when a revision is provided but --contents is not provided.
Generating such a commit in that case would combine the currently
checked out file contents with the provided revision, which breaks
normal blame behavior and produces unexpected results.

This enables use of --contents with an arbitrary revision, rather than
forcing the use of the local HEAD commit. This makes the --contents
option significantly more flexible, as it is no longer required to check
out the working tree to the desired commit before using --contents.

Reword the documentation so that its clear that --contents can be used
with <rev>.

Add tests for the --contents option to the annotate-tests.sh test
script.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-03-24 12:05:22 -07:00

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-b::
Show blank SHA-1 for boundary commits. This can also
be controlled via the `blame.blankBoundary` config option.
--root::
Do not treat root commits as boundaries. This can also be
controlled via the `blame.showRoot` config option.
--show-stats::
Include additional statistics at the end of blame output.
-L <start>,<end>::
-L :<funcname>::
Annotate only the line range given by '<start>,<end>',
or by the function name regex '<funcname>'.
May be specified multiple times. Overlapping ranges are allowed.
+
'<start>' and '<end>' are optional. `-L <start>` or `-L <start>,` spans from
'<start>' to end of file. `-L ,<end>` spans from start of file to '<end>'.
+
include::line-range-format.txt[]
-l::
Show long rev (Default: off).
-t::
Show raw timestamp (Default: off).
-S <revs-file>::
Use revisions from revs-file instead of calling linkgit:git-rev-list[1].
--reverse <rev>..<rev>::
Walk history forward instead of backward. Instead of showing
the revision in which a line appeared, this shows the last
revision in which a line has existed. This requires a range of
revision like START..END where the path to blame exists in
START. `git blame --reverse START` is taken as `git blame
--reverse START..HEAD` for convenience.
--first-parent::
Follow only the first parent commit upon seeing a merge
commit. This option can be used to determine when a line
was introduced to a particular integration branch, rather
than when it was introduced to the history overall.
-p::
--porcelain::
Show in a format designed for machine consumption.
--line-porcelain::
Show the porcelain format, but output commit information for
each line, not just the first time a commit is referenced.
Implies --porcelain.
--incremental::
Show the result incrementally in a format designed for
machine consumption.
--encoding=<encoding>::
Specifies the encoding used to output author names
and commit summaries. Setting it to `none` makes blame
output unconverted data. For more information see the
discussion about encoding in the linkgit:git-log[1]
manual page.
--contents <file>::
Pretend the file being annotated has a commit with the
contents from the named file and a parent of <rev>,
defaulting to HEAD when no <rev> is specified. You may
specify '-' to make the command read from the standard
input for the file contents.
--date <format>::
Specifies the format used to output dates. If --date is not
provided, the value of the blame.date config variable is
used. If the blame.date config variable is also not set, the
iso format is used. For supported values, see the discussion
of the --date option at linkgit:git-log[1].
--[no-]progress::
Progress status is reported on the standard error stream
by default when it is attached to a terminal. This flag
enables progress reporting even if not attached to a
terminal. Can't use `--progress` together with `--porcelain`
or `--incremental`.
-M[<num>]::
Detect moved or copied lines within a file. When a commit
moves or copies a block of lines (e.g. the original file
has A and then B, and the commit changes it to B and then
A), the traditional 'blame' algorithm notices only half of
the movement and typically blames the lines that were moved
up (i.e. B) to the parent and assigns blame to the lines that
were moved down (i.e. A) to the child commit. With this
option, both groups of lines are blamed on the parent by
running extra passes of inspection.
+
<num> is optional but it is the lower bound on the number of
alphanumeric characters that Git must detect as moving/copying
within a file for it to associate those lines with the parent
commit. The default value is 20.
-C[<num>]::
In addition to `-M`, detect lines moved or copied from other
files that were modified in the same commit. This is
useful when you reorganize your program and move code
around across files. When this option is given twice,
the command additionally looks for copies from other
files in the commit that creates the file. When this
option is given three times, the command additionally
looks for copies from other files in any commit.
+
<num> is optional but it is the lower bound on the number of
alphanumeric characters that Git must detect as moving/copying
between files for it to associate those lines with the parent
commit. And the default value is 40. If there are more than one
`-C` options given, the <num> argument of the last `-C` will
take effect.
--ignore-rev <rev>::
Ignore changes made by the revision when assigning blame, as if the
change never happened. Lines that were changed or added by an ignored
commit will be blamed on the previous commit that changed that line or
nearby lines. This option may be specified multiple times to ignore
more than one revision. If the `blame.markIgnoredLines` config option
is set, then lines that were changed by an ignored commit and attributed to
another commit will be marked with a `?` in the blame output. If the
`blame.markUnblamableLines` config option is set, then those lines touched
by an ignored commit that we could not attribute to another revision are
marked with a '*'.
--ignore-revs-file <file>::
Ignore revisions listed in `file`, which must be in the same format as an
`fsck.skipList`. This option may be repeated, and these files will be
processed after any files specified with the `blame.ignoreRevsFile` config
option. An empty file name, `""`, will clear the list of revs from
previously processed files.
--color-lines::
Color line annotations in the default format differently if they come from
the same commit as the preceding line. This makes it easier to distinguish
code blocks introduced by different commits. The color defaults to cyan and
can be adjusted using the `color.blame.repeatedLines` config option.
--color-by-age::
Color line annotations depending on the age of the line in the default format.
The `color.blame.highlightRecent` config option controls what color is used for
each range of age.
-h::
Show help message.