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
#require killdaemons
$ hg clone http://localhost:$HGPORT/ copy
abort: * (glob)
[255]
$ test -d copy
[1]
This server doesn't do range requests so it's basically only good for
one pull
$ python "$TESTDIR/dumbhttp.py" -p $HGPORT --pid dumb.pid
$ cat dumb.pid >> $DAEMON_PIDS
$ hg init remote
$ cd remote
$ echo foo > bar
$ echo c2 > '.dotfile with spaces'
$ hg add
adding .dotfile with spaces
adding bar
$ hg commit -m"test"
$ hg tip
changeset: 0:02770d679fb8
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: test
$ cd ..
$ hg clone static-http://localhost:$HGPORT/remote local
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 2 changes to 2 files
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd local
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
2 files, 1 changesets, 2 total revisions
$ cat bar
foo
$ cd ../remote
$ echo baz > quux
$ hg commit -A -mtest2
adding quux
check for HTTP opener failures when cachefile does not exist
$ rm .hg/cache/*
$ cd ../local
$ cat >> .hg/hgrc <<EOF
> [hooks]
> changegroup = sh -c "printenv.py changegroup"
> EOF
$ hg pull
pulling from static-http://localhost:$HGPORT/remote
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
changegroup hook: HG_HOOKNAME=changegroup HG_HOOKTYPE=changegroup HG_NODE=4ac2e3648604439c580c69b09ec9d93a88d93432 HG_NODE_LAST=4ac2e3648604439c580c69b09ec9d93a88d93432 HG_SOURCE=pull HG_TXNID=TXN:$ID$ HG_URL=http://localhost:$HGPORT/remote
(run 'hg update' to get a working copy)
trying to push
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo more foo >> bar
$ hg commit -m"test"
$ hg push
pushing to static-http://localhost:$HGPORT/remote
abort: destination does not support push
[255]
trying clone -r
$ cd ..
$ hg clone -r doesnotexist static-http://localhost:$HGPORT/remote local0
abort: unknown revision 'doesnotexist'!
[255]
$ hg clone -r 0 static-http://localhost:$HGPORT/remote local0
adding changesets
adding manifests
adding file changes
added 1 changesets with 2 changes to 2 files
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
test with "/" URI (issue747) and subrepo
$ hg init
$ hg init sub
$ touch sub/test
$ hg -R sub commit -A -m "test"
adding test
$ hg -R sub tag not-empty
$ echo sub=sub > .hgsub
$ echo a > a
$ hg add a .hgsub
$ hg -q ci -ma
$ hg clone static-http://localhost:$HGPORT/ local2
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 3 changes to 3 files
updating to branch default
cloning subrepo sub from static-http://localhost:$HGPORT/sub
requesting all changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd local2
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
3 files, 1 changesets, 3 total revisions
checking subrepo links
$ cat a
a
$ hg paths
default = static-http://localhost:$HGPORT/
test with empty repo (issue965)
$ cd ..
$ hg init remotempty
$ hg clone static-http://localhost:$HGPORT/remotempty local3
no changes found
updating to branch default
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd local3
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
0 files, 0 changesets, 0 total revisions
$ hg paths
default = static-http://localhost:$HGPORT/remotempty
test with non-repo
$ cd ..
$ mkdir notarepo
$ hg clone static-http://localhost:$HGPORT/notarepo local3
abort: 'http://localhost:$HGPORT/notarepo' does not appear to be an hg repository!
[255]
$ killdaemons.py