Re: [PATCH v12 0/7] 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
>               * D
>         * E
>           * F
>             * G
>               * H
>           * I
>         * J1
>         * J2
>
> The indentation wraps after cascading columns and when wrapping back to
> the initial column if the next commit is a non-visual-root commit, force
> the indentation one extra level.
>
> Series explanation:
>
> 1. Cleanup to bring a common function from t4215 and t6016 that will be
>    used in t4218.
>
> 2. Logic extraction of the chose of from where the commit source comes
>    from.
>
> 3. Add a buffer for lookahead purposes.
>
> 4. Principal commit. Implement the logic to get the visual roots
>    indented.
>
> 5. Make visual root cascading wrap after 4 columns
>
> 6. Add --[no-]graph-indent and log.graphIndent options.
>
> GitHub CI: https://github.com/pabloosabaterr/git/actions/runs/29331144667
>
> [1]: https://lore.kernel.org/git/xmqqwnwajbuj.fsf@gitster.c.googlers.com/
>
> V11 DIFF:
>
> - Changed the check that required graph, to not confuse because it is a
>   boolean value.
>
> - Typos
>
> Signed-off-by: Pablo Sabater <pabloosabaterr@gmail.com>
> ---
> Pablo Sabater (7):
>       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: wrap cascading commits after 4 columns
>       graph: move config reading into graph_read_config()
>       graph: add --[no-]graph-indent and log.graphIndent
>
>  Documentation/config/log.adoc              |   4 +
>  Documentation/rev-list-options.adoc        |   8 +
>  graph.c                                    | 332 +++++++++++++++-
>  graph.h                                    |  17 +
>  revision.c                                 |  57 ++-
>  revision.h                                 |   2 +
>  t/lib-log-graph.sh                         |   5 +
>  t/meson.build                              |   1 +
>  t/t4215-log-skewed-merges.sh               |  33 +-
>  t/t4218-log-graph-indentation.sh           | 596 +++++++++++++++++++++++++++++
>  t/t6016-rev-list-graph-simplify-history.sh |  25 +-
>  11 files changed, 1032 insertions(+), 48 deletions(-)
>
> Range-diff versus v11:
>
> 1:  dd0bb0d215 = 1:  d754392142 lib-log-graph: move check_graph function
> 2:  07e239533d = 2:  c93c2c0771 revision: add next_commit_to_show()
> 3:  4d71f674a1 = 3:  70fe612ae1 graph: add a 2 commit buffer for lookahead
> 4:  48ad2562f0 = 4:  e1ac06c4ea graph: indent visual root in graph
> 5:  45be69d11b = 5:  ce52b41527 graph: wrap cascading commits after 4 columns
> 6:  8ce53ae21b = 6:  9b7bb2cebc graph: move config reading into graph_read_config()
> 7:  c1fa81022e ! 7:  13e830725f graph: add --[no-]graph-indent and log.graphIndent
>     @@ Documentation/rev-list-options.adoc: This implies the `--topo-order` option by d
>      +  When used with `--graph`, indent visual roots (commits with no parents
>      +  or whose parents are not shown) to differentiate them from commits that
>      +  are vertically adjacent but unrelated. Enabled by default. Use
>     -+  `--no-graph-indent` to disable or set `graph.indent` to set a deafault
>     -+  preference.
>     ++  `--no-graph-indent` to disable or set `log.graphIndent` to set a
>     ++  default preference.
>      +
>       ifdef::git-rev-list[]
>       `--count`::
>     @@ revision.c: int setup_revisions(int argc, const char **argv, struct rev_info *re
>         if (revs->graph_max_lanes > 0 && !revs->graph)
>                 die(_("the option '%s' requires '%s'"), "--graph-lane-limit", "--graph");
>
>     -+  if (revs->graph_indent_set > 0 && !revs->graph)
>     ++  if (revs->graph_indent_set && !revs->graph)
>      +          die(_("the option '%s' requires '%s'"), "--[no-]graph-indent", "--graph");
>      +
>         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
>     @@ t/t4218-log-graph-indentation.sh: test_expect_success 'visual root cascading get
>      +  EOF
>      +'
>      +
>     -+# graph.indent true and no --option is the default state.
>     ++# log.graphIndent unset and no --option (which activates graph indentation) is
>     ++# the default state.
>      +
>       test_done
>
> ---
> base-commit: f60db8d575adb79761d363e026fb49bddf330c73