view tests/test-diff-hashes.t @ 33269:ead6749354e1

phabricator: try to fetch differential revisions in batch

Previously, we read Differential Revisions one by one by calling
`differential.query`.

Fetching them one by one is suboptimal. Unfortunately, there is no Conduit
API that allows us to get a stack of diffids using a single API call.

This patch tries to be smarter using a simple heuristic: when fetching D59
as a stack, previous IDs like D51, D52, D53, ..., D58 are likely belonging
to a same stack so just fetch them as well. Since `differential.query` only
returns cheap metadata without expensive diff content, it shouldn't be a big
problem for the server.

Using a test Phabricator instance, this patch reduces `phabread` reading a
10 patch stack from about 13 to 30 seconds to 8 seconds.

  $ hg init a
  $ cd a

  $ hg diff inexistent1 inexistent2
  inexistent1: * (glob)
  inexistent2: * (glob)

  $ echo bar > foo
  $ hg add foo
  $ hg ci -m 'add foo'

  $ echo foobar > foo
  $ hg ci -m 'change foo'

  $ hg --quiet diff -r 0 -r 1
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -bar
  +foobar

  $ hg diff -r 0 -r 1
  diff -r a99fb63adac3 -r 9b8568d3af2f foo
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -bar
  +foobar

  $ hg --verbose diff -r 0 -r 1
  diff -r a99fb63adac3 -r 9b8568d3af2f foo
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -bar
  +foobar

  $ hg --debug diff -r 0 -r 1
  diff -r a99fb63adac3f31816a22f665bc3b7a7655b30f4 -r 9b8568d3af2f1749445eef03aede868a6f39f210 foo
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -bar
  +foobar

  $ cd ..