worker: rewrite error handling so os._exit covers all cases
Previously the worker error handling is like:
pid = os.fork() --+
if pid == 0: |
.... | problematic
.... --+
try: --+
.... | worker error handling
--+
If a signal arrives when Python is executing the "problematic" lines, an
external error handling (dispatch.py) will take over the control flow and
it's no longer guaranteed "os._exit" is called (see
86cd09bc13ba for why it
is necessary).
This patch rewrites the error handling so it covers all possible code paths
for a worker even during fork.
Note: "os.getpid() == parentpid" is used to test if the process is parent or
not intentionally, instead of checking "pid", because "pid = os.fork()" may
be not atomic - it's possible that that a signal hits the worker before the
assignment completes [1]. The newly added test replaces "os.fork" to
exercise that extreme case.
[1]: CPython compiles "pid = os.fork()" to 2 byte codes: "CALL_FUNCTION" and
"STORE_FAST", so it's probably not atomic:
def f():
pid = os.fork()
dis.dis(f)
2 0 LOAD_GLOBAL 0 (os)
3 LOAD_ATTR 1 (fork)
6 CALL_FUNCTION 0
9 STORE_FAST 0 (pid)
12 LOAD_CONST 0 (None)
15 RETURN_VALUE
$ cat <<EOF >> $HGRCPATH
> [extensions]
> purge =
> EOF
init
$ hg init t
$ cd t
setup
$ echo r1 > r1
$ hg ci -qAmr1 -d'0 0'
$ mkdir directory
$ echo r2 > directory/r2
$ hg ci -qAmr2 -d'1 0'
$ echo 'ignored' > .hgignore
$ hg ci -qAmr3 -d'2 0'
delete an empty directory
$ mkdir empty_dir
$ hg purge -p -v
empty_dir
$ hg purge -v
removing directory empty_dir
$ ls
directory
r1
delete an untracked directory
$ mkdir untracked_dir
$ touch untracked_dir/untracked_file1
$ touch untracked_dir/untracked_file2
$ hg purge -p
untracked_dir/untracked_file1
untracked_dir/untracked_file2
$ hg purge -v
removing file untracked_dir/untracked_file1
removing file untracked_dir/untracked_file2
removing directory untracked_dir
$ ls
directory
r1
delete an untracked file
$ touch untracked_file
$ touch untracked_file_readonly
$ python <<EOF
> import os, stat
> f= 'untracked_file_readonly'
> os.chmod(f, stat.S_IMODE(os.stat(f).st_mode) & ~stat.S_IWRITE)
> EOF
$ hg purge -p
untracked_file
untracked_file_readonly
$ hg purge -v
removing file untracked_file
removing file untracked_file_readonly
$ ls
directory
r1
delete an untracked file in a tracked directory
$ touch directory/untracked_file
$ hg purge -p
directory/untracked_file
$ hg purge -v
removing file directory/untracked_file
$ ls
directory
r1
delete nested directories
$ mkdir -p untracked_directory/nested_directory
$ hg purge -p
untracked_directory/nested_directory
$ hg purge -v
removing directory untracked_directory/nested_directory
removing directory untracked_directory
$ ls
directory
r1
delete nested directories from a subdir
$ mkdir -p untracked_directory/nested_directory
$ cd directory
$ hg purge -p
untracked_directory/nested_directory
$ hg purge -v
removing directory untracked_directory/nested_directory
removing directory untracked_directory
$ cd ..
$ ls
directory
r1
delete only part of the tree
$ mkdir -p untracked_directory/nested_directory
$ touch directory/untracked_file
$ cd directory
$ hg purge -p ../untracked_directory
untracked_directory/nested_directory
$ hg purge -v ../untracked_directory
removing directory untracked_directory/nested_directory
removing directory untracked_directory
$ cd ..
$ ls
directory
r1
$ ls directory/untracked_file
directory/untracked_file
$ rm directory/untracked_file
skip ignored files if --all not specified
$ touch ignored
$ hg purge -p
$ hg purge -v
$ ls
directory
ignored
r1
$ hg purge -p --all
ignored
$ hg purge -v --all
removing file ignored
$ ls
directory
r1
abort with missing files until we support name mangling filesystems
$ touch untracked_file
$ rm r1
hide error messages to avoid changing the output when the text changes
$ hg purge -p 2> /dev/null
untracked_file
$ hg st
! r1
? untracked_file
$ hg purge -p
untracked_file
$ hg purge -v 2> /dev/null
removing file untracked_file
$ hg st
! r1
$ hg purge -v
$ hg revert --all --quiet
$ hg st -a
tracked file in ignored directory (issue621)
$ echo directory >> .hgignore
$ hg ci -m 'ignore directory'
$ touch untracked_file
$ hg purge -p
untracked_file
$ hg purge -v
removing file untracked_file
skip excluded files
$ touch excluded_file
$ hg purge -p -X excluded_file
$ hg purge -v -X excluded_file
$ ls
directory
excluded_file
r1
$ rm excluded_file
skip files in excluded dirs
$ mkdir excluded_dir
$ touch excluded_dir/file
$ hg purge -p -X excluded_dir
$ hg purge -v -X excluded_dir
$ ls
directory
excluded_dir
r1
$ ls excluded_dir
file
$ rm -R excluded_dir
skip excluded empty dirs
$ mkdir excluded_dir
$ hg purge -p -X excluded_dir
$ hg purge -v -X excluded_dir
$ ls
directory
excluded_dir
r1
$ rmdir excluded_dir
skip patterns
$ mkdir .svn
$ touch .svn/foo
$ mkdir directory/.svn
$ touch directory/.svn/foo
$ hg purge -p -X .svn -X '*/.svn'
$ hg purge -p -X re:.*.svn
$ rm -R .svn directory r1
only remove files
$ mkdir -p empty_dir dir
$ touch untracked_file dir/untracked_file
$ hg purge -p --files
dir/untracked_file
untracked_file
$ hg purge -v --files
removing file dir/untracked_file
removing file untracked_file
$ ls
dir
empty_dir
$ ls dir
only remove dirs
$ mkdir -p empty_dir dir
$ touch untracked_file dir/untracked_file
$ hg purge -p --dirs
empty_dir
$ hg purge -v --dirs
removing directory empty_dir
$ ls
dir
untracked_file
$ ls dir
untracked_file
remove both files and dirs
$ mkdir -p empty_dir dir
$ touch untracked_file dir/untracked_file
$ hg purge -p --files --dirs
dir/untracked_file
untracked_file
empty_dir
$ hg purge -v --files --dirs
removing file dir/untracked_file
removing file untracked_file
removing directory empty_dir
removing directory dir
$ ls
$ cd ..