[PATCH] subrepo: handle missing subrepo spec file as removed

Martin Geisler mg at aragost.com
Thu Nov 18 02:08:25 CST 2010


Patrick Mézard <pmezard at gmail.com> writes:

> Le 17/11/10 22:27, Patrick Mezard a écrit :
>
> [...]
>
>> +delete .hgsubstate and update
>> +
>> +  $ hg up -C
>> +  warning: subrepo spec file .hgsub not found
>> +  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
>> +  $ rm .hgsubstate
>> +  $ hg up 0  
>> +  remote changed .hgsubstate which local deleted
>> +  use (c)hanged version or leave (d)eleted? c
>> +  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
>> +  $ hg st
>> +  $ ls subrepo
>> +  a
>
> The test is interesting because it highlights .hgsubstate magical
> behaviour: it is first deleted, then on the update the merge machinery
> kicks in and eventually merge it by restoring and overwriting it.

Interesting... the .hgsubstate file is in many ways a ghost file: it is
written or updated just before commit so 'hg status' or 'hg diff' will
not reveal the pending change, and yet the file is there in the next
changeset. I think "magic" is just the right word to describe it :)

> Also, I am not sure what to expect in the update case:
> 1- The current situation where the missing .hgsub spec is apparently
> ignored (I admit I have not investigated the reasons for the merge
> result)
>
> 2- A situation where the missing spec file is considered removed and
> act accordingly. But if .hgsub is there and .hgsubstate is missing,
> what should be done?

Both of these situations are inconsistent and broken -- it is part of
the design of subrepos that there must always be a .hgsubstate file if
there is a .hgsub file, as I know you're aware.

But when there is a .hgsub file and no .hgsubstate file, then I would
expect Mercurial to behave like it does when you first add a .hgsub
file: there you have no .hgsubstate file and it is automatically built
on the next commit.

When .hgsubstate is deleted in revision 2 and you updated to revision 1
and leave it deleted, then I guess the subrepos should be left in the
state they were in before the update. The next commit will then record a
.hgsubstate file that looks like the deleted one from revision 2.

> Not sure all this really matters now, my initial issue was to avoid
> "breaking" the working directory.

Yes, I agree that is more important.

-- 
Martin Geisler

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