tests: ensure a status will have non ambiguous mtime in some race test

For the test to work, we need some mtime to be recorded. For them to be recorded, they need to be "clearly in the past", otherwise edit with the same mtime would be possible.

Strictly speaking there might be file system with a minimal mtime increment
longer than one second. However it is unlikely that we will run the test on
them for now. We can be smarter about this in the future if it becomes
necessary.

Differential Revision: https://phab.mercurial-scm.org/D11779

tests/test-dirstate-race.t

@@ -1,247 +1,248 b''
 #testcases dirstate-v1 dirstate-v2
 
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
   > exp-rc-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
 #endif
 
   $ hg init repo
   $ cd repo
   $ echo a > a
   $ hg add a
   $ hg commit -m test
 
 Do we ever miss a sub-second change?:
 
   $ for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
   >     hg update -qC 0
   >     echo b > a
   >     hg st
   > done
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
   M a
 
   $ echo test > b
   $ mkdir dir1
   $ echo test > dir1/c
   $ echo test > d
 
   $ echo test > e
 #if execbit
 A directory will typically have the execute bit -- make sure it doesn't get
 confused with a file with the exec bit set
   $ chmod +x e
 #endif
 
   $ hg add b dir1 d e
   adding dir1/c
   $ hg commit -m test2
 
   $ cat >> $TESTTMP/dirstaterace.py << EOF
   > from mercurial import (
   >     context,
   >     extensions,
   > )
   > def extsetup(ui):
   >     extensions.wrapfunction(context.workingctx, '_checklookup', overridechecklookup)
   > def overridechecklookup(orig, self, files):
   >     # make an update that changes the dirstate from underneath
   >     self._repo.ui.system(br"sh '$TESTTMP/dirstaterace.sh'",
   >                          cwd=self._repo.root)
   >     return orig(self, files)
   > EOF
 
   $ hg debugrebuilddirstate
   $ hg debugdirstate
   n   0         -1 unset               a
   n   0         -1 unset               b
   n   0         -1 unset               d
   n   0         -1 unset               dir1/c
   n   0         -1 unset               e
 
 XXX Note that this returns M for files that got replaced by directories. This is
 definitely a bug, but the fix for that is hard and the next status run is fine
 anyway.
 
   $ cat > $TESTTMP/dirstaterace.sh <<EOF
   > rm b && rm -r dir1 && rm d && mkdir d && rm e && mkdir e
   > EOF
 
+  $ sleep 1 # ensure non-ambiguous mtime
   $ hg status --config extensions.dirstaterace=$TESTTMP/dirstaterace.py
   M d
   M e
   ! b
   ! dir1/c
   $ hg debugdirstate
   n 644          2 * a (glob)
   n   0         -1 unset               b
   n   0         -1 unset               d
   n   0         -1 unset               dir1/c
   n   0         -1 unset               e
 
   $ hg status
   ! b
   ! d
   ! dir1/c
   ! e
 
   $ rmdir d e
   $ hg update -C -q .
 
 Test that dirstate changes aren't written out at the end of "hg
 status", if .hg/dirstate is already changed simultaneously before
 acquisition of wlock in workingctx._poststatusfixup().
 
 This avoidance is important to keep consistency of dirstate in race
 condition (see issue5584 for detail).
 
   $ hg parents -q
   1:* (glob)
 
   $ hg debugrebuilddirstate
   $ hg debugdirstate
   n   0         -1 unset               a
   n   0         -1 unset               b
   n   0         -1 unset               d
   n   0         -1 unset               dir1/c
   n   0         -1 unset               e
 
   $ cat > $TESTTMP/dirstaterace.sh <<EOF
   > # This script assumes timetable of typical issue5584 case below:
   > #
   > # 1. "hg status" loads .hg/dirstate
   > # 2. "hg status" confirms clean-ness of FILE
   > # 3. "hg update -C 0" updates the working directory simultaneously
   > #    (FILE is removed, and FILE is dropped from .hg/dirstate)
   > # 4. "hg status" acquires wlock
   > #    (.hg/dirstate is re-loaded = no FILE entry in dirstate)
   > # 5. "hg status" marks FILE in dirstate as clean
   > #    (FILE entry is added to in-memory dirstate)
   > # 6. "hg status" writes dirstate changes into .hg/dirstate
   > #    (FILE entry is written into .hg/dirstate)
   > #
   > # To reproduce similar situation easily and certainly, #2 and #3
   > # are swapped.  "hg cat" below ensures #2 on "hg status" side.
   > 
   > hg update -q -C 0
   > hg cat -r 1 b > b
   > EOF
 
 "hg status" below should excludes "e", of which exec flag is set, for
 portability of test scenario, because unsure but missing "e" is
 treated differently in _checklookup() according to runtime platform.
 
 - "missing(!)" on POSIX, "pctx[f].cmp(self[f])" raises ENOENT
 - "modified(M)" on Windows, "self.flags(f) != pctx.flags(f)" is True
 
   $ hg status --config extensions.dirstaterace=$TESTTMP/dirstaterace.py --debug -X path:e
   skip updating dirstate: identity mismatch
   M a
   ! d
   ! dir1/c
 
   $ hg parents -q
   0:* (glob)
   $ hg files
   a
   $ hg debugdirstate
   n * * * a (glob)
 
   $ rm b
 
 #if fsmonitor
 
 Create fsmonitor state.
 
   $ hg status
   $ f --type .hg/fsmonitor.state
   .hg/fsmonitor.state: file
 
 Test that invalidating fsmonitor state in the middle (which doesn't require the
 wlock) causes the fsmonitor update to be skipped.
 hg debugrebuilddirstate ensures that the dirstaterace hook will be called, but
 it also invalidates the fsmonitor state. So back it up and restore it.
 
   $ mv .hg/fsmonitor.state .hg/fsmonitor.state.tmp
   $ hg debugrebuilddirstate
   $ mv .hg/fsmonitor.state.tmp .hg/fsmonitor.state
 
   $ cat > $TESTTMP/dirstaterace.sh <<EOF
   > rm .hg/fsmonitor.state
   > EOF
 
   $ hg status --config extensions.dirstaterace=$TESTTMP/dirstaterace.py --debug
   skip updating fsmonitor.state: identity mismatch
   $ f .hg/fsmonitor.state
   .hg/fsmonitor.state: file not found
 
 #endif
 
 Set up a rebase situation for issue5581.
 
   $ echo c2 > a
   $ echo c2 > b
   $ hg add b
   $ hg commit -m c2
   created new head
   $ echo c3 >> a
   $ hg commit -m c3
   $ hg update 2
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo c4 >> a
   $ echo c4 >> b
   $ hg commit -m c4
   created new head
 
 Configure a merge tool that runs status in the middle of the rebase. The goal of
 the status call is to trigger a potential bug if fsmonitor's state is written
 even though the wlock is held by another process. The output of 'hg status' in
 the merge tool goes to /dev/null because we're more interested in the results of
 'hg status' run after the rebase.
 
   $ cat >> $TESTTMP/mergetool-race.sh << EOF
   > echo "custom merge tool"
   > printf "c2\nc3\nc4\n" > \$1
   > hg --cwd "$TESTTMP/repo" status > /dev/null
   > echo "custom merge tool end"
   > EOF
   $ cat >> $HGRCPATH << EOF
   > [extensions]
   > rebase =
   > [merge-tools]
   > test.executable=sh
   > test.args=$TESTTMP/mergetool-race.sh \$output
   > EOF
 
   $ hg rebase -s . -d 3 --tool test
   rebasing 4:b08445fd6b2a tip "c4"
   merging a
   custom merge tool
   custom merge tool end
   saved backup bundle to $TESTTMP/repo/.hg/strip-backup/* (glob)
 
 This hg status should be empty, whether or not fsmonitor is enabled (issue5581).
 
   $ hg status