Patchwork rebase: add boolean config item rebase.norebasesource

# HG changeset patch
# User C. Masloch <pushbx@ulukai.org>
# Date 1650475479 -7200
#      Wed Apr 20 19:24:39 2022 +0200
# Node ID 4fd9ac0558249d24552b9efeed1ac77452c73319
# Parent  f45e1618cbf68aca4e72b6fed8dd2acef6f39a10
rebase: add boolean config item rebase.norebasesource

This allows to use rebase without recording a rebase_source extra
field. This is useful for example to build a mirror converted from
another SCM (such as svn) by converting only new revisions, and
then incrementally add them to the destination by pulling from the
newly converted (unrelated) repo and rebasing the new revisions
onto the last old already stored changeset. Without this patch the
rebased changesets would always receive some rebase_source that
would depend on the particular history of the conversion process,
instead of only depending on the original source revisions.

This is used to implement a hg mirror repo of SvarDOS (a partially
nonfree but completely redistributable DOS distribution) in the
scripts at https://hg.pushbx.org/ecm/svardos.scr/

In particular, cre.sh creates an svn mirror, upd.sh recreates an
entire hg repo from the svn mirror (which takes too long to do in a
regular job), and akt.sh uses hg convert with the config item
convert.svn.startrev to incrementally convert only the two most
recent revisions already found in the mirror destination plus any
possible new revisions. If any are found, the temporary repo's
changesets are pulled into the destination (as changesets from an
unrelated repository). Then the changesets corresponding to the new
revisions are rebased onto the prior final changeset. (Finally, the
two remaining duplicates of the prior head and its parent are
stripped from the destination repository.)

Without this patch, the particular rebase_source extra field would
depend on the order and times at which akt.sh was used, instead of
only depending on the source repository. In other words, whatever
sequence of upd.sh and akt.sh is used at whatever times, it is
desired that the final output repositories always match each other
exactly.

> On Apr 20, 2022, at 2:19 PM, C. Masloch <pushbx@ulukai.org> wrote:
> 
> # HG changeset patch
> # User C. Masloch <pushbx@ulukai.org>
> # Date 1650475479 -7200
> #      Wed Apr 20 19:24:39 2022 +0200
> # Node ID 4fd9ac0558249d24552b9efeed1ac77452c73319
> # Parent  f45e1618cbf68aca4e72b6fed8dd2acef6f39a10
> rebase: add boolean config item rebase.norebasesource
> 
> This allows to use rebase without recording a rebase_source extra
> field. This is useful for example to build a mirror converted from
> another SCM (such as svn) by converting only new revisions, and
> then incrementally add them to the destination by pulling from the
> newly converted (unrelated) repo and rebasing the new revisions
> onto the last old already stored changeset. Without this patch the
> rebased changesets would always receive some rebase_source that
> would depend on the particular history of the conversion process,
> instead of only depending on the original source revisions.

Interesting. An unusual process.

> 
> This is used to implement a hg mirror repo of SvarDOS (a partially
> nonfree but completely redistributable DOS distribution) in the
> scripts at https://hg.pushbx.org/ecm/svardos.scr/
> 
> In particular, cre.sh creates an svn mirror, upd.sh recreates an
> entire hg repo from the svn mirror (which takes too long to do in a
> regular job), and akt.sh uses hg convert with the config item
> convert.svn.startrev to incrementally convert only the two most
> recent revisions already found in the mirror destination plus any
> possible new revisions. If any are found, the temporary repo's
> changesets are pulled into the destination (as changesets from an
> unrelated repository). Then the changesets corresponding to the new
> revisions are rebased onto the prior final changeset. (Finally, the
> two remaining duplicates of the prior head and its parent are
> stripped from the destination repository.)
> 
> Without this patch, the particular rebase_source extra field would
> depend on the order and times at which akt.sh was used, instead of
> only depending on the source repository. In other words, whatever
> sequence of upd.sh and akt.sh is used at whatever times, it is
> desired that the final output repositories always match each other
> exactly.
> 
> diff --git a/hgext/rebase.py b/hgext/rebase.py
> --- a/hgext/rebase.py
> +++ b/hgext/rebase.py
> @@ -547,7 +547,10 @@
>         date = self.date
>         if date is None:
>             date = ctx.date()
> -        extra = {b'rebase_source': ctx.hex()}
> +        if repo.ui.configbool(b'rebase', b'norebasesource'):
> +            extra = {}
> +        else:
> +            extra = {b'rebase_source': ctx.hex()}
>         for c in self.extrafns:
>             c(ctx, extra)
>         destphase = max(ctx.phase(), phases.draft)
> diff --git a/mercurial/configitems.py b/mercurial/configitems.py
> --- a/mercurial/configitems.py
> +++ b/mercurial/configitems.py
> @@ -2770,3 +2770,8 @@
>     b'experimental.inmemory',
>     default=False,
> )
> +coreconfigitem(
> +    b'rebase',
> +    b'norebasesource',
> +    default=False,
> +)

I’m basically fine with this, but:

1) could you add some description in a comment about what this does here
2) could you mark it as experimental=True so it’s hidden from mundane uses?

Thanks!

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