Re: [PATCH v3] doc-diff: don't `cd_to_toplevel`

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Junio,

On Thu, 7 Feb 2019, Junio C Hamano wrote:

> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
> 
> > Even when there are even only as much as 12 merge bases to test (which is
> > the current number of merge bases between `next` and `pu`),...
> > ...
> > And I sadly have to report that that's not the end of it. Back when I
> > implemented the automatic bisect after failed builds (for details, see
> > https://github.com/git-for-windows/build-extra/commit/c7e01e82c), I had to
> > turn it off real quickly because the dumb bisect between `next` and `pu`
> > regularly ran into the 4h timeout.
> 
> Would it make it easier for you if you substituted all the mention
> of 'next' in your message with 'pu^{/^### match next}'?  

I was working on this in 2017, and could not make it to work as I wanted.
Ever since, that bisect code has been dormant.

In the meantime, I was able to parallelize the test suite enough to make
it feasible to test the topic branches. That usually takes care of things
really quickly, and I just bite the bullet and bisect manually.

Ciao,
Dscho

> 
> That mid-point between 'master' and 'pu' is designed to contain
> exactly the same set of non-merge commits 'next' has, with the tree
> that is identical to that of 'next', and from there to the tip of
> 'pu' forms a single strand of merges of tips of topic branches that
> are not yet merged to 'next' (by definition, it itself is the merge
> base of it and 'pu').
> 
> Bisecting along the first-parent chain from there to the tip of 'pu'
> would let us identify which merge is faulty as the first-and-quick
> pass and currently there are about 20 merges in that range on the
> first-parent chain.
> 
>