Re: [PATCH 2/3 v3] Teach git-rev-list --ignore-merge-bases

[Antonio Russo <antonio.e.russo@gmail.com>]

On 5/2/20 7:25 AM, Johannes Sixt wrote:
> Am 01.05.20 um 16:22 schrieb Antonio Russo:
>> +--ignore-merge-bases::
>> +	Show commits that are introduced by each merge before showing
>> +	the first parent of the merge but remove edges from those commits
>> +	to commits reachable from the first parent. When used with
>> +	`--graph`, this can help visualize repositories with many merges
>> +	when you are not interested in the merge base used for each
>> +	merge. It also reduces the width of the graph visualization
>> +	when used with `--graph`.
> 
> I wonder whether there is some potential to prettify another aspect of
> --graph once this feature is in place: In particular, when I *am*
> interested in merge-bases, I use --boundary, and I get this chart:
> 
> $ git log --graph --boundary --oneline --no-decorate 7d28d69174~4..7d28d69174
> 
> *   7d28d69174 Merge branch 'jc/allow-strlen-substitution-in-shell-scripts'
> |\  
> | * 78725ebda9 CodingGuidelines: allow ${#posix} == strlen($posix)
> * |   dfdce31ce6 Merge branch 'en/pull-do-not-rebase-after-fast-forwarding'
> |\ \  
> | * | fbae70ddc6 pull: avoid running both merge and rebase
> | |/  
> * |   b660a76d0f Merge branch 'dl/wrapper-fix-indentation'
> |\ \  
> | * | 7cd54d37dc wrapper: indent with tabs
> * | |   3d6c56dd66 Merge branch 'ag/sequencer-i18n-messages'
> |\ \ \  
> | * | | 4d55d63bde sequencer: mark messages for translation
> | o | | 3bab5d5625 The second batch post 2.26 cycle
> |  / /  
> o / / 9f471e4b95 Merge branch 'rs/pull-options-sync-code-and-doc'
>  / /  
> o / 0b6806b9e4 xread, xwrite: limit size of IO to 8MB
>  /  
> o b6d4d82bd5 msvc: accommodate for vcpkg's upgrade to OpenSSL v1.1.x
> 
> but I would prefer to see something like this:
> 
> *   7d28d69174 Merge branch 'jc/allow-strlen-substitution-in-shell-scripts'
> |\  
> | * 78725ebda9 CodingGuidelines: allow ${#posix} == strlen($posix)
> * |   dfdce31ce6 Merge branch 'en/pull-do-not-rebase-after-fast-forwarding'
> |\ \  
> | * | fbae70ddc6 pull: avoid running both merge and rebase
> | |/
> | o b6d4d82bd5 msvc: accommodate for vcpkg's upgrade to OpenSSL v1.1.x  
> *   b660a76d0f Merge branch 'dl/wrapper-fix-indentation'
> |\  
> | * 7cd54d37dc wrapper: indent with tabs
> | o 0b6806b9e4 xread, xwrite: limit size of IO to 8MB
> *   3d6c56dd66 Merge branch 'ag/sequencer-i18n-messages'
> |\  
> | * 4d55d63bde sequencer: mark messages for translation
> | o 3bab5d5625 The second batch post 2.26 cycle
> o 9f471e4b95 Merge branch 'rs/pull-options-sync-code-and-doc'
> 
> Maybe that is just an easy fall-out?

Yeah, I noticed this too.  What we want is to create a spanning tree by left-first
DFS (amputating edges connecting to already visited vertices), and then walk the
amputated tree in a right-first DFS (and then not sort the commits any further).

The tricky part is getting the results of the right-first DFS before the left-first
(amputation) DFS finishes.  I'm working on it.

>> diff --git a/object.h b/object.h
>> index b22328b838..0bf6fb0d55 100644
>> --- a/object.h
>> +++ b/object.h
>> @@ -59,7 +59,7 @@ struct object_array {
>>
>>  /*
>>   * object flag allocation:
>> - * revision.h:               0---------10         15                   25----28
>> + * revision.h:               0---------10         15                   23----28
> 
> I think the intent is that the line is like a ruler with marks: you
> should move "23" sufficiently far to the left, because the "23" mark
> cannot be at the same spot where the "25" mark was.

I though this was only a schematic ruler, but, counting it now, it is exact.
I'll fix it.

> (I'm not reviewing this patch as I am illiterate when it comes to the
> revision walker, I just happened to notice this when I skimmed the
> patch.)

Thank you,
Antonio