view tests/test-subrepo-paths.t @ 30418:1156ec81f709

util: improve iterfile so it chooses code path wisely

We have performance concerns on "iterfile" as it is 4X slower on normal
files. While modern systems have the nice property that reading a "fast"
(on-disk) file cannot be interrupted and should be made use of.

This patch dumps the related knowledge in comments. And "iterfile" chooses
code paths wisely:

  1. If it's CPython 3, or PyPY, use the fast path.
  2. If fp is a normal file, use the fast path.
  3. If fp is not a normal file and CPython version >= 2.7.4, use the same
     workaround (4x slower) as before.
  4. If fp is not a normal file and CPython version < 2.7.4, use another
     workaround (2x slower but may block longer then necessary) which
     basically re-invents the buffer + readline logic in Python.

This will give us good confidence on both correctness and performance
dealing with EINTR in iterfile(fp) for all known supported Python versions.

  $ hg init outer
  $ cd outer

  $ echo '[paths]' >> .hg/hgrc
  $ echo 'default = http://example.net/' >> .hg/hgrc

hg debugsub with no remapping

  $ echo 'sub = libfoo' > .hgsub
  $ hg add .hgsub

  $ hg debugsub
  path sub
   source   libfoo
   revision 

hg debugsub with remapping

  $ echo '[subpaths]' >> .hg/hgrc
  $ printf 'http://example.net/lib(.*) = C:\\libs\\\\1-lib\\\n' >> .hg/hgrc

  $ hg debugsub
  path sub
   source   C:\libs\foo-lib\
   revision 

test cumulative remapping, the $HGRCPATH file is loaded first

  $ echo '[subpaths]' >> $HGRCPATH
  $ echo 'libfoo = libbar' >> $HGRCPATH
  $ hg debugsub
  path sub
   source   C:\libs\bar-lib\
   revision 

test absolute source path -- testing with a URL is important since
standard os.path.join wont treat that as an absolute path

  $ echo 'abs = http://example.net/abs' > .hgsub
  $ hg debugsub
  path abs
   source   http://example.net/abs
   revision 

  $ echo 'abs = /abs' > .hgsub
  $ hg debugsub
  path abs
   source   /abs
   revision 

test bad subpaths pattern

  $ cat > .hg/hgrc <<EOF
  > [subpaths]
  > .* = \1
  > EOF
  $ hg debugsub
  abort: bad subrepository pattern in $TESTTMP/outer/.hg/hgrc:2: invalid group reference (glob)
  [255]

  $ cd ..