tests/test-blackbox.t

revlog: change generaldelta delta parent heuristic

The old generaldelta heuristic was "if p1 (or p2) was closer than the last full text,
use it, otherwise use prev". This was problematic when a repo contained multiple
branches that were very different. If commits to branch A were pushed, and the
last full text was branch B, it would generate a fulltext. Then if branch B was
pushed, it would generate another fulltext. The problem is that the last
fulltext (and delta'ing against `prev` in general) has no correlation with the
contents of the incoming revision, and therefore will always have degenerate
cases.

According to the blame, that algorithm was chosen to minimize the chain length.
Since there is already code that protects against that (the delta-vs-fulltext
code), and since it has been improved since the original generaldelta algorithm
went in (2011), I believe the chain length criteria will still be preserved.

The new algorithm always diffs against p1 (or p2 if it's closer), unless the
resulting delta will fail the delta-vs-fulltext check, in which case we delta
against prev.

Some before and after stats on manifest.d size.

internal large repo
old heuristic - 2.0 GB
new heuristic - 1.2 GB

mozilla-central
old heuristic - 242 MB
new heuristic - 261 MB

The regression in mozilla central is due to the new heuristic choosing p2r as
the delta when it's closer to the tip. Switching the algorithm to always prefer
p1r brings the size back down (242 MB). This is result of the way in which
mozilla does merges and pushes, and the result could easily swing the other
direction in other repos (depending on if they merge X into Y or Y into X), but
will never be as degenerate as before.

I future patch will address the regression by introducing an optional, even more
aggressive delta heuristic which will knock the mozilla manifest size down
dramatically.

setup
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > blackbox=
  > mock=$TESTDIR/mockblackbox.py
  > mq=
  > EOF
  $ hg init blackboxtest
  $ cd blackboxtest

command, exit codes, and duration

  $ echo a > a
  $ hg add a
  $ hg blackbox
  1970/01/01 00:00:00 bob> add a
  1970/01/01 00:00:00 bob> add a exited 0 after * seconds (glob)

incoming change tracking

create two heads to verify that we only see one change in the log later
  $ hg commit -ma
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo b > b
  $ hg commit -Amb
  adding b
  created new head

clone, commit, pull
  $ hg clone . ../blackboxtest2
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo c > c
  $ hg commit -Amc
  adding c
  $ cd ../blackboxtest2
  $ hg pull
  pulling from $TESTTMP/blackboxtest (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  (run 'hg update' to get a working copy)
  $ hg blackbox -l 5
  1970/01/01 00:00:00 bob> pull
  1970/01/01 00:00:00 bob> updated served branch cache in ?.???? seconds (glob)
  1970/01/01 00:00:00 bob> wrote served branch cache with 1 labels and 2 nodes
  1970/01/01 00:00:00 bob> 1 incoming changes - new heads: d02f48003e62
  1970/01/01 00:00:00 bob> pull exited 0 after * seconds (glob)

we must not cause a failure if we cannot write to the log

  $ hg rollback
  repository tip rolled back to revision 1 (undo pull)

#if unix-permissions no-root
  $ chmod 000 .hg/blackbox.log
  $ hg --debug incoming
  warning: cannot write to blackbox.log: Permission denied
  comparing with $TESTTMP/blackboxtest (glob)
  query 1; heads
  searching for changes
  all local heads known remotely
  changeset:   2:d02f48003e62c24e2659d97d30f2a83abe5d5d51
  tag:         tip
  phase:       draft
  parent:      1:6563da9dcf87b1949716e38ff3e3dfaa3198eb06
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    2:ab9d46b053ebf45b7996f2922b9893ff4b63d892
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      c
  extra:       branch=default
  description:
  c
  
  
#endif
  $ hg pull
  pulling from $TESTTMP/blackboxtest (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  (run 'hg update' to get a working copy)

a failure reading from the log is fine
#if unix-permissions no-root
  $ hg blackbox -l 3
  abort: Permission denied: $TESTTMP/blackboxtest2/.hg/blackbox.log
  [255]

  $ chmod 600 .hg/blackbox.log
#endif

backup bundles get logged

  $ touch d
  $ hg commit -Amd
  adding d
  created new head
  $ hg strip tip
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/blackboxtest2/.hg/strip-backup/*-backup.hg (glob)
  $ hg blackbox -l 5
  1970/01/01 00:00:00 bob> strip tip
  1970/01/01 00:00:00 bob> saved backup bundle to $TESTTMP/blackboxtest2/.hg/strip-backup/*-backup.hg (glob)
  1970/01/01 00:00:00 bob> updated base branch cache in ?.???? seconds (glob)
  1970/01/01 00:00:00 bob> wrote base branch cache with 1 labels and 2 nodes
  1970/01/01 00:00:00 bob> strip tip exited 0 after * seconds (glob)

extension and python hooks - use the eol extension for a pythonhook

  $ echo '[extensions]' >> .hg/hgrc
  $ echo 'eol=' >> .hg/hgrc
  $ echo '[hooks]' >> .hg/hgrc
  $ echo 'update = echo hooked' >> .hg/hgrc
  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  hooked
  $ hg blackbox -l 5
  1970/01/01 00:00:00 bob> update
  1970/01/01 00:00:00 bob> writing .hg/cache/tags2-visible with 0 tags
  1970/01/01 00:00:00 bob> pythonhook-preupdate: hgext.eol.preupdate finished in * seconds (glob)
  1970/01/01 00:00:00 bob> exthook-update: echo hooked finished in * seconds (glob)
  1970/01/01 00:00:00 bob> update exited 0 after * seconds (glob)

log rotation

  $ echo '[blackbox]' >> .hg/hgrc
  $ echo 'maxsize = 20 b' >> .hg/hgrc
  $ echo 'maxfiles = 3' >> .hg/hgrc
  $ hg status
  $ hg status
  $ hg status
  $ hg tip -q
  2:d02f48003e62
  $ ls .hg/blackbox.log*
  .hg/blackbox.log
  .hg/blackbox.log.1
  .hg/blackbox.log.2

cleanup
  $ cd ..