[PATCH 0/2] Option to modify revision mark for root commits

This patch series allows --show-linear-break to be used with --graph, allowing for the revision mark to be changed for root commits.

Feel free to squash away PATCH 1, or maybe even discard PATCH 2.

Jason: tested against Cygwin x86_64/release/git/git-2.30.0-1-src.tar.xz

Note: PATCH 2 revision.c:2410 makes a second copy of optarg. This may
not be necessary.

Background:

The use case is --graph --oneline with unrelated histories. For example, in a hypothetical repository with an orphaned "prebuilt" branch containing builds of the master branch, the history may look like:

kmarek@kyle-ppc64le /tmp/somerepo
$ git log --graph --all --oneline
* 02190b6 (prebuilt) add aarch64
* 7b873f6 add x86_64
* 26cc783 add ppc64le
* 5b7186e (HEAD -> master) add Makefile
* ea69093 implement cmdline parsing
* a65df8a add main.c
* 7727eb3 Initial commit

At first sight, the above log implies that 26cc783's parent is 5b7186e, or that master is an ancestor to prebuilt, but 26cc783 is the start of a new history:

kmarek@kyle-ppc64le /tmp/somerepo
$ git log --graph --oneline master
* 5b7186e (HEAD -> master) add Makefile
* ea69093 implement cmdline parsing
* a65df8a add main.c
* 7727eb3 Initial commit

kmarek@kyle-ppc64le /tmp/somerepo
$ git log --graph --oneline prebuilt
* 02190b6 (prebuilt) add aarch64
* 7b873f6 add x86_64
* 26cc783 add ppc64le

To identify the start of a new history:

kmarek@kyle-ppc64le /tmp/somerepo
$ git log --graph --all --oneline --show-linear-break
* 02190b6 (prebuilt) add aarch64
* 7b873f6 add x86_64
# 26cc783 add ppc64le
* 5b7186e (HEAD -> master) add Makefile
* ea69093 implement cmdline parsing
* a65df8a add main.c
# 7727eb3 Initial commit

kmarek@kyle-ppc64le /tmp/somerepo
$ git log --graph --all --oneline --show-linear-break=I
* 02190b6 (prebuilt) add aarch64
* 7b873f6 add x86_64
I 26cc783 add ppc64le
* 5b7186e (HEAD -> master) add Makefile
* ea69093 implement cmdline parsing
* a65df8a add main.c
I 7727eb3 Initial commit

Kyle Marek (2):
  revision: Denote root commits with '#'
  revision: implement --show-linear-break for --graph

 Documentation/rev-list-options.txt |  7 +++++++
 log-tree.c                         |  2 +-
 revision.c                         | 10 ++++++----
 revision.h                         |  1 +
 4 files changed, 15 insertions(+), 5 deletions(-)