hgweb: do not import uuid immediately to avoid its side effect
With hgdemandimport disabled (chg's case), `import uuid` has an immediate
side effect calling `ctypes.util.find_library` trying to locate the
`libuuid` library. This happens at `import` time before `dispatch.run()`.
The call trace is like:
File "hg/hg", line 54, in <module>
from mercurial import (
File "hg/mercurial/dispatch.py", line 24, in <module>
from . import (
File "hg/mercurial/commands.py", line 23, in <module>
from . import (
File "hg/mercurial/help.py", line 33, in <module>
from .hgweb import (
File "hg/mercurial/hgweb/__init__.py", line 20, in <module>
from . import (
File "hg/mercurial/hgweb/hgweb_mod.py", line 14, in <module>
from .common import (
File "hg/mercurial/hgweb/common.py", line 15, in <module>
import uuid
File "/usr/lib64/python2.7/uuid.py", line 404, in <module>
lib = ctypes.CDLL(ctypes.util.find_library(libname))
The problem is, `ctypes.util.find_library` will execute
`sh -c '/sbin/ldconfig -p 2>/dev/null'` on Python <= 2.7.12. The output of
`sh` may pollute the terminal:
shell-init: error retrieving current directory: getcwd: cannot access
parent directories: No such file or directory
This patch moves `import uuid` so its side-effect can only happen after the
cwd check in `dispatch._getlocal`. Therefore the terminal won't be
polluted by importing `uuid`.
Differential Revision: https://phab.mercurial-scm.org/D1024
$ cat <<EOF > merge
> import sys, os
> print("merging for", os.path.basename(sys.argv[1]))
> EOF
$ HGMERGE="$PYTHON ../merge"; export HGMERGE
$ hg init A1
$ cd A1
$ echo This is file foo1 > foo
$ echo This is file bar1 > bar
$ hg add foo bar
$ hg commit -m "commit text"
$ cd ..
$ hg clone A1 B1
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd A1
$ rm bar
$ hg remove bar
$ hg commit -m "commit test"
$ cd ../B1
$ echo This is file foo22 > foo
$ hg commit -m "commit test"
$ cd ..
$ hg clone A1 A2
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg clone B1 B2
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd A1
$ hg pull ../B1
pulling from ../B1
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m "commit test"
bar should remain deleted.
$ hg manifest --debug
f9b0e817f6a48de3564c6b2957687c5e7297c5a0 644 foo
$ cd ../B2
$ hg pull ../A2
pulling from ../A2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg merge
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m "commit test"
bar should remain deleted.
$ hg manifest --debug
f9b0e817f6a48de3564c6b2957687c5e7297c5a0 644 foo
$ cd ..