"bzr branch --stacked lp:<foo>" uses 5 HPSS connections

[Andrew Bennetts]

5 connections — 4 of them doing VFS calls — are made for a single branch --stacked operation:

andrew@steerpike:/tmp$ bzr -Dhpss branch --stacked lp:testtools
Source repository format does not support stacking, using format:
  Packs 5 (adds stacking support, requires bzr 1.6)
Source branch format does not support stacking, using format:
  Branch format 7
Created new stacked branch referring to bzr+ssh://bazaar.launchpad.net/~jml/testtools/trunk/.
HPSS calls: 14 (9 vfs) SmartSSHClientMedium(connected=False, username=u'spiv', host='bazaar.launchpad.net', port=None)
HPSS calls: 28 (23 vfs) SmartSSHClientMedium(connected=False, username=u'spiv', host='bazaar.launchpad.net', port=None)
HPSS calls: 11 (0 vfs) SmartSSHClientMedium(connected=False, username=u'spiv', host='bazaar.launchpad.net', port=None)
HPSS calls: 8 (3 vfs) SmartSSHClientMedium(connected=False, username=u'spiv', host='bazaar.launchpad.net', port=None)
HPSS calls: 9 (4 vfs) SmartSSHClientMedium(connected=False, username=u'spiv', host='bazaar.launchpad.net', port=None)

(the format warnings are irrelevant, this happens to 2a branches too)

Creating stacked branches locally isn't a particularly common operation, but 5 connections is pretty ridiculous!

[Jonathan Lange (jml)]

Is the lp: part significant?

[Andrew Bennetts (spiv)]

jml: no, I don't think the lp: part is particularly significant. Just the use of --stacked is causing the sprout code to be a bit foolish I think.

FWIW bzr trunk is a bit better than the original report, a mere 3 connections (where 1 would do, of course):

$ bzr branch --stacked lp:testtools
Created new stacked branch referring to bzr+ssh://bazaar.launchpad.net/%2Bbranch/testtools/.
Transferred: 601kB (12.1kB/s r:588kB w:13kB)
HPSS calls: 46 (41 vfs) SmartSSHClientMedium(bzr+ssh://<email address hidden>/)
HPSS calls: 9 (0 vfs) SmartSSHClientMedium(bzr+ssh://<email address hidden>/)
HPSS calls: 8 (4 vfs) SmartSSHClientMedium(bzr+ssh://<email address hidden>/)