"Derrick Stolee via GitGitGadget" <gitgitgadget@xxxxxxxxx> writes:
> From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
> Subject: Re: [PATCH v2 1/2] graph: fix case that hit assert()
>
> A failure was reported in "git log --graph --all" with the new
> graph-rendering logic. The code fails an assert() statement when
> collapsing multiple edges from a merge.
>
> The assert was introduced by eaf158f8 (graph API: Use horizontal
> lines for more compact graphs, 2009-04-21), which is quite old.
> This assert is trying to say that when we complete a horizontal
> line with a single slash, it is because we have reached our target.
>
> This assertion is hit when we have two collapsing lines from the
> same merge commit, as follows:
>
> | | | | *
> | |_|_|/|
> |/| | |/
> | | |/|
> | |/| |
> | * | |
> * | | |
I was sort-of expecting to see
graph: drop assert() for merge with two collapsing parents
When "git log --graph" shows a merge commit that has two collapsing
lines, like:
| | | | *
| |_|_|/|
|/| | |/
| | |/|
| |/| |
| * | |
* | | |
we trigger an assert():
graph.c:1228: graph_output_collapsing_line: Assertion
`graph->mapping[i - 3] == target' failed.
The assert was introduced by eaf158f8 ("graph API: Use horizontal
lines for more compact graphs", 2009-04-21), which is quite old.
...
near the beginning of this commit, though.
> In a larger example, the current code will output a collapse
> as follows:
>
> | | | | | | *
> | |_|_|_|_|/|\
> |/| | | | |/ /
> | | | | |/| /
> | | | |/| |/
> | | |/| |/|
> | |/| |/| |
> | | |/| | |
> | | * | | |
>
> However, the intended collapse should allow multiple horizontal lines
> as follows:
>
> | | | | | | *
> | |_|_|_|_|/|\
> |/| | | | |/ /
> | | |_|_|/| /
> | |/| | | |/
> | | | |_|/|
> | | |/| | |
> | | * | | |
>
> This behavior is not corrected by this change, but is noted for a later
> update.
This part is new and looks like a good thing to mention.
