Re: [PATCH v9 0/4] graph: indent visual roots in graph

> When rendering a graph, if the history contains multiple "visual roots",
> actual roots or commits that look like roots (i.e. have their parents
> filtered out) can end up being vertically adjacent to unrelated commits,
> falsely appearing to be related.
> 
> A fix for this issue was already attempted [1] a while ago.
> 
> This series adds indentation to the visual root commits, so they cannot be
> vertically adjacent anymore making it easier to identify them.
> 
> Before indentation:
> 
> 	* A
> 	* B1
> 	* B2
> 	* C1
> 	* C2
> 
> After indentation:
> 
> 	  * A
> 	* B1
> 	 \
> 	  * B2
> 	* C1
> 	* C2
> 
> Indents the visual root commits that have still commits to show after
> them, and if they have children it connects them with an edge at a new
> row.
> 
> If there are multiple visual roots adjacent in history, the indentation
> starts with the second one, avoiding redundant indentation of the first
> one and cascades after the second.
> 
> 	* A
> 	  * B
> 	    * C
> 	* D1
> 	* D2
> 
> This series first commit is a cleanup that brings a common function
> from t4215 and t6016 to a graph functions file which they both use, so
> the new test file for indentation, t4218, can use it as well.
> 
> GitHub CI: https://github.com/pabloosabaterr/git/actions/runs/29154333559
> 
> [1]: https://lore.kernel.org/git/xmqqwnwajbuj.fsf@gitster.c.googlers.com/
> 
> V8 DIFF:
> 
> - Checking if the parents of a commit are NULL is not enough to know if
>   the commit is a visual root due to options that filter the commit
>   parents but they do not remove them (--author, --grep, etc).
>   At graph_is_visual_root_candidate(), iterate the parents and call
>   graph_is_interesting() for each of them to know whether they will be
>   shown or not.
> - Add a --author and a --grep test.
> 
> Signed-off-by: Pablo Sabater <pabloosabaterr@gmail.com>
> 
> ---
> Pablo Sabater (4):
>       lib-log-graph: move check_graph function
>       revision: add next_commit_to_show()
>       graph: add a 2 commit buffer for lookahead
>       graph: indent visual root in graph
> 
>  graph.c                                    | 295 +++++++++++++++++
>  graph.h                                    |  17 +
>  revision.c                                 |  48 ++-
>  t/lib-log-graph.sh                         |   5 +
>  t/meson.build                              |   1 +
>  t/t4215-log-skewed-merges.sh               |  33 +-
>  t/t4218-log-graph-indentation.sh           | 514 +++++++++++++++++++++++++++++
>  t/t6016-rev-list-graph-simplify-history.sh |  25 +-
>  8 files changed, 893 insertions(+), 45 deletions(-)