view tests/test-websub.t @ 31478:9335dc6b2a9c

pager: avoid shell=True on subprocess.Popen for better errors (issue5491)

man(1) behaves as poorly as Mercurial without this change. This cribs
from git's run-command[0], which has a list of characters that imply a
string that needs to be run using 'sh -c'. If none of those characters
are present in the command string, we can use shell=False mode on
subprocess and get significantly better error messages (see the test)
when the pager process is invalid. With a complicated pager command
(that contains one of the unsafe characters), we behave as we do today
(which is no worse than git manages.)

I briefly tried tapdancing in a thread to catch early pager exits, but
it's just too perilous: you get races between fd duping operations and
a bad pager exiting, and it's too hard to differentiate between a
slow-bad-pager result and a fast-human-quit-pager-early result.

I've observed some weird variation in exit code handling in the "bad
experience" case in test-pager.t: on my Mac hg predictably exits
nonzero, but on Linux hg always exits zero in that case. For now,
we'll work around it with || true. :(

0: https://github.com/git/git/blob/cddbda4bc87b9d2c985b6749b1cf026b15e2d3e7/run-command.c#L201

#require serve

  $ hg init test
  $ cd test

  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > # this is only necessary to check that the mapping from
  > # interhg to websub works
  > interhg =
  > 
  > [websub]
  > issues = s|Issue(\d+)|<a href="http://bts.example.org/issue\1">Issue\1</a>|
  > 
  > [interhg]
  > # check that we maintain some interhg backwards compatibility...
  > # yes, 'x' is a weird delimiter...
  > markbugs = sxbugx<i class="\x">bug</i>x
  > EOF

  $ touch foo
  $ hg add foo
  $ hg commit -d '1 0' -m 'Issue123: fixed the bug!'

  $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
  $ cat hg.pid >> $DAEMON_PIDS

log

  $ get-with-headers.py localhost:$HGPORT "rev/tip" | grep bts
  <div class="description"><a href="http://bts.example.org/issue123">Issue123</a>: fixed the <i class="x">bug</i>!</div>
errors

  $ cat errors.log

  $ cd ..