[PATCH] graphlog: draw multiple edges towards null node (issue5440)

[Ryan McElroy]

On 3/20/17 8:22 AM, Yuya Nishihara wrote:
> # HG changeset patch
> # User Yuya Nishihara <yuya at tcha.org>
> # Date 1489978255 -32400
> #      Mon Mar 20 11:50:55 2017 +0900
> # Node ID db70a30dde5182e704b02b0e47a79d3ecfafdd49
> # Parent  cede8eaf55e2fe68434c273cfd066512b5ca112e
> graphlog: draw multiple edges towards null node (issue5440)
>
> Before, edge (r, null) was processed only once by newparents. However what
> we really need is just stripping the edge (null, null).
>
> diff --git a/mercurial/graphmod.py b/mercurial/graphmod.py
> --- a/mercurial/graphmod.py
> +++ b/mercurial/graphmod.py
> @@ -182,6 +182,9 @@ def asciiedges(type, char, lines, state,
>       knownparents = []
>       newparents = []
>       for ptype, parent in parents:
> +        if parent == rev:
> +            # self reference (should only be seen in null rev)
> +            continue
>           if parent in seen:
>               knownparents.append(parent)
>           else:
> @@ -191,8 +194,7 @@ def asciiedges(type, char, lines, state,
>       ncols = len(seen)
>       nextseen = seen[:]
>       nextseen[nodeidx:nodeidx + 1] = newparents
> -    edges = [(nodeidx, nextseen.index(p))
> -             for p in knownparents if p != nullrev]
> +    edges = [(nodeidx, nextseen.index(p)) for p in knownparents]
>   
>       seen[:] = nextseen
>       while len(newparents) > 2:
> diff --git a/tests/test-glog.t b/tests/test-glog.t
> --- a/tests/test-glog.t
> +++ b/tests/test-glog.t
> @@ -3424,3 +3424,39 @@ the right node styles are used (issue517
>        summary:     0
>     
>   
> +  $ cd ..
> +
> +Multiple roots (issue5440):
> +
> +  $ hg init multiroots
> +  $ cd multiroots
> +  $ cat <<EOF > .hg/hgrc
> +  > [ui]
> +  > logtemplate = '{rev} {desc}\n\n'
> +  > EOF
> +
> +  $ touch foo
> +  $ hg ci -Aqm foo
> +  $ hg co -q null
> +  $ touch bar
> +  $ hg ci -Aqm bar
> +
> +  $ hg log -Gr null:
> +  @  1 bar
> +  |
> +  | o  0 foo
> +  |/
> +  o  -1
> +
> +  $ hg log -Gr null+0
> +  o  0 foo
> +  |
> +  o  -1
> +
> +  $ hg log -Gr null+1
> +  @  1 bar
> +  |
> +  o  -1
> +
> +
> +  $ cd ..

I'd like to re-state for the record my wish that for subtle bugfixes 
like this that we could split the fix into two patches: a patch that 
adds a test exhibiting the broken behavior, and then the fix with the 
corrections to the test. That would make it *so much easier* to review a 
patch like this.

For the curious (like me), the previous (broken) behavior was this (note 
the missing /):

    @  1 bar
    |
    | o  0 foo
|
    o  -1

The difference in the test output with this patch is thus:

    @  1 bar
    |
    | o  0 foo
-  |
+  |/
    o  -1

Overall, this change looks good to me.