[Monotone-devel] mtnplain (aka dumb) revision order, epoch

[Zbigniew Zagórski]

Hi,

Recently I recognized that plain (aka dumb) that is rather far from working with
mtn 0.26.
On 0.27 it's better because it works on windows (automate stdio newlines fixed).
There is a problem with revision reordering which I almost fixed in my sandbox.

This fix is to recognize all the certs received by Feeder and
queue them accordingly to the type:
- fdata   - write them immediately
- fdelta  - write them immediately
- pubkey  - queue
- rdata  - queue
- rcert  - queue
Then when everything is fed to the Feeder:
- write all 'pubkey' - this probably can go unordered
- write all 'rdata' (*)
- write all 'rcert'

(*) The hack is with writing rdata in correct order. Currently after writing
each rdata packet mtn 'stderr' is checked if contains:
   missing prerequisite revision 'REVID'
and if text is found then this revision is queued as a child of REVID. Then when
REVID is written then all its children are queued again.

This is almost correct but certainly that 'stderr' matching is awfully evil. Yes
i know.
Question: How to obtain parent REV(s) from rdata packet without using 'mtn read'
?


Second problem.
After finishing packet reordering I found that 'mtnplain' 'pull' to a clean
database fails.
This error was after following steps:
 1. 'mtnplain' -d DB.mtn push SOMEPLACE
 2. mtn -d DB2.mtn db init
 3. 'mtnplain' -d DB2.mtn pull SOMEPLACE
 4. mtn -D DB2.mtn pull file:DB.mtn
4th step was to check if all data were transfered by mtnplain if yes - netsync
should transfer nothing; but apparently mtn failed with following error
------------
|06:07:16#23|address@hidden|..umb/plain-zbigg|$ mtn -d DB2.mtn pull file:DB.mtn
'net.*'
mtn: connecting to file:DB.mtn
mtn: finding items to synchronize:
mtn: certificates | keys | revisions
mtn:          162 |    3 |        54
mtn: warning: error: Mismatched epoch on branch net.venge.monotone.dumb. Server
has
'e748431d4147df17a39df80f0c2d72c9d2fa9fb2', client has
'0000000000000000000000000000000000000000'.
mtn: peer file:DB.mtn disconnected after we informed them of error
mtn: warning: protocol error while processing peer stdio: 'received network
error: Mismatched epoch on branch net.venge.
monotone.dumb. Server has 'e748431d4147df17a39df80f0c2d72c9d2fa9fb2', client has
'0000000000000000000000000000000000000000'.'
mtn: bytes in | bytes out | certs in | revs in
mtn:      129 |       235 |        0 |       0
------------

Hmm, what is epoch and what should I do while exporting/importing to preserve
epoch of a branch?

PS. I think that 'plain' is better name for 'dumb'. And my proposition is
to name the tool is 'mtnplain'.

PS2. Here is latest version of 'mtnplain'
  http://zzagorski.strony.wi.ps.pl/mtnplain/mtnplain-0.0.3.zip

--
Best regards,  Zbyszek