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 >> $HGRCPATH << EOF
> [extensions]
> share =
> EOF
store and revlogv1 are required in source
$ hg --config format.usestore=false init no-store
$ hg -R no-store debugupgraderepo
abort: cannot upgrade repository; requirement missing: store
[255]
$ hg init no-revlogv1
$ cat > no-revlogv1/.hg/requires << EOF
> dotencode
> fncache
> generaldelta
> store
> EOF
$ hg -R no-revlogv1 debugupgraderepo
abort: cannot upgrade repository; requirement missing: revlogv1
[255]
Cannot upgrade shared repositories
$ hg init share-parent
$ hg -q share share-parent share-child
$ hg -R share-child debugupgraderepo
abort: cannot upgrade repository; unsupported source requirement: shared
[255]
Do not yet support upgrading manifestv2 and treemanifest repos
$ hg --config experimental.manifestv2=true init manifestv2
$ hg -R manifestv2 debugupgraderepo
abort: cannot upgrade repository; unsupported source requirement: manifestv2
[255]
$ hg --config experimental.treemanifest=true init treemanifest
$ hg -R treemanifest debugupgraderepo
abort: cannot upgrade repository; unsupported source requirement: treemanifest
[255]
Cannot add manifestv2 or treemanifest requirement during upgrade
$ hg init disallowaddedreq
$ hg -R disallowaddedreq --config experimental.manifestv2=true --config experimental.treemanifest=true debugupgraderepo
abort: cannot upgrade repository; do not support adding requirement: manifestv2, treemanifest
[255]
An upgrade of a repository created with recommended settings only suggests optimizations
$ hg init empty
$ cd empty
$ hg debugupgraderepo
(no feature deficiencies found in existing repository)
performing an upgrade with "--run" will make the following changes:
requirements
preserved: dotencode, fncache, generaldelta, revlogv1, store
additional optimizations are available by specifying "--optimize <name>":
redeltaparent
deltas within internal storage will be recalculated to choose an optimal base revision where this was not already done; the size of the repository may shrink and various operations may become faster; the first time this optimization is performed could slow down upgrade execution considerably; subsequent invocations should not run noticeably slower
redeltamultibase
deltas within internal storage will be recalculated against multiple base revision and the smallest difference will be used; the size of the repository may shrink significantly when there are many merges; this optimization will slow down execution in proportion to the number of merges in the repository and the amount of files in the repository; this slow down should not be significant unless there are tens of thousands of files and thousands of merges
redeltaall
deltas within internal storage will always be recalculated without reusing prior deltas; this will likely make execution run several times slower; this optimization is typically not needed
--optimize can be used to add optimizations
$ hg debugupgrade --optimize redeltaparent
(no feature deficiencies found in existing repository)
performing an upgrade with "--run" will make the following changes:
requirements
preserved: dotencode, fncache, generaldelta, revlogv1, store
redeltaparent
deltas within internal storage will choose a new base revision if needed
additional optimizations are available by specifying "--optimize <name>":
redeltamultibase
deltas within internal storage will be recalculated against multiple base revision and the smallest difference will be used; the size of the repository may shrink significantly when there are many merges; this optimization will slow down execution in proportion to the number of merges in the repository and the amount of files in the repository; this slow down should not be significant unless there are tens of thousands of files and thousands of merges
redeltaall
deltas within internal storage will always be recalculated without reusing prior deltas; this will likely make execution run several times slower; this optimization is typically not needed
Various sub-optimal detections work
$ cat > .hg/requires << EOF
> revlogv1
> store
> EOF
$ hg debugupgraderepo
repository lacks features recommended by current config options:
fncache
long and reserved filenames may not work correctly; repository performance is sub-optimal
dotencode
storage of filenames beginning with a period or space may not work correctly
generaldelta
deltas within internal storage are unable to choose optimal revisions; repository is larger and slower than it could be; interaction with other repositories may require extra network and CPU resources, making "hg push" and "hg pull" slower
performing an upgrade with "--run" will make the following changes:
requirements
preserved: revlogv1, store
added: dotencode, fncache, generaldelta
fncache
repository will be more resilient to storing certain paths and performance of certain operations should be improved
dotencode
repository will be better able to store files beginning with a space or period
generaldelta
repository storage will be able to create optimal deltas; new repository data will be smaller and read times should decrease; interacting with other repositories using this storage model should require less network and CPU resources, making "hg push" and "hg pull" faster
additional optimizations are available by specifying "--optimize <name>":
redeltaparent
deltas within internal storage will be recalculated to choose an optimal base revision where this was not already done; the size of the repository may shrink and various operations may become faster; the first time this optimization is performed could slow down upgrade execution considerably; subsequent invocations should not run noticeably slower
redeltamultibase
deltas within internal storage will be recalculated against multiple base revision and the smallest difference will be used; the size of the repository may shrink significantly when there are many merges; this optimization will slow down execution in proportion to the number of merges in the repository and the amount of files in the repository; this slow down should not be significant unless there are tens of thousands of files and thousands of merges
redeltaall
deltas within internal storage will always be recalculated without reusing prior deltas; this will likely make execution run several times slower; this optimization is typically not needed
$ hg --config format.dotencode=false debugupgraderepo
repository lacks features recommended by current config options:
fncache
long and reserved filenames may not work correctly; repository performance is sub-optimal
generaldelta
deltas within internal storage are unable to choose optimal revisions; repository is larger and slower than it could be; interaction with other repositories may require extra network and CPU resources, making "hg push" and "hg pull" slower
repository lacks features used by the default config options:
dotencode
storage of filenames beginning with a period or space may not work correctly
performing an upgrade with "--run" will make the following changes:
requirements
preserved: revlogv1, store
added: fncache, generaldelta
fncache
repository will be more resilient to storing certain paths and performance of certain operations should be improved
generaldelta
repository storage will be able to create optimal deltas; new repository data will be smaller and read times should decrease; interacting with other repositories using this storage model should require less network and CPU resources, making "hg push" and "hg pull" faster
additional optimizations are available by specifying "--optimize <name>":
redeltaparent
deltas within internal storage will be recalculated to choose an optimal base revision where this was not already done; the size of the repository may shrink and various operations may become faster; the first time this optimization is performed could slow down upgrade execution considerably; subsequent invocations should not run noticeably slower
redeltamultibase
deltas within internal storage will be recalculated against multiple base revision and the smallest difference will be used; the size of the repository may shrink significantly when there are many merges; this optimization will slow down execution in proportion to the number of merges in the repository and the amount of files in the repository; this slow down should not be significant unless there are tens of thousands of files and thousands of merges
redeltaall
deltas within internal storage will always be recalculated without reusing prior deltas; this will likely make execution run several times slower; this optimization is typically not needed
$ cd ..
Upgrading a repository that is already modern essentially no-ops
$ hg init modern
$ hg -R modern debugupgraderepo --run
upgrade will perform the following actions:
requirements
preserved: dotencode, fncache, generaldelta, revlogv1, store
beginning upgrade...
repository locked and read-only
creating temporary repository to stage migrated data: $TESTTMP/modern/.hg/upgrade.* (glob)
(it is safe to interrupt this process any time before data migration completes)
data fully migrated to temporary repository
marking source repository as being upgraded; clients will be unable to read from repository
starting in-place swap of repository data
replaced files will be backed up at $TESTTMP/modern/.hg/upgradebackup.* (glob)
replacing store...
store replacement complete; repository was inconsistent for *s (glob)
finalizing requirements file and making repository readable again
removing temporary repository $TESTTMP/modern/.hg/upgrade.* (glob)
copy of old repository backed up at $TESTTMP/modern/.hg/upgradebackup.* (glob)
the old repository will not be deleted; remove it to free up disk space once the upgraded repository is verified
Upgrading a repository to generaldelta works
$ hg --config format.usegeneraldelta=false init upgradegd
$ cd upgradegd
$ touch f0
$ hg -q commit -A -m initial
$ touch f1
$ hg -q commit -A -m 'add f1'
$ hg -q up -r 0
$ touch f2
$ hg -q commit -A -m 'add f2'
$ hg debugupgraderepo --run
upgrade will perform the following actions:
requirements
preserved: dotencode, fncache, revlogv1, store
added: generaldelta
generaldelta
repository storage will be able to create optimal deltas; new repository data will be smaller and read times should decrease; interacting with other repositories using this storage model should require less network and CPU resources, making "hg push" and "hg pull" faster
beginning upgrade...
repository locked and read-only
creating temporary repository to stage migrated data: $TESTTMP/upgradegd/.hg/upgrade.* (glob)
(it is safe to interrupt this process any time before data migration completes)
migrating 9 total revisions (3 in filelogs, 3 in manifests, 3 in changelog)
migrating 341 bytes in store; 401 bytes tracked data
migrating 3 filelogs containing 3 revisions (0 bytes in store; 0 bytes tracked data)
finished migrating 3 filelog revisions across 3 filelogs; change in size: 0 bytes
migrating 1 manifests containing 3 revisions (157 bytes in store; 220 bytes tracked data)
finished migrating 3 manifest revisions across 1 manifests; change in size: 0 bytes
migrating changelog containing 3 revisions (184 bytes in store; 181 bytes tracked data)
finished migrating 3 changelog revisions; change in size: 0 bytes
finished migrating 9 total revisions; total change in store size: 0 bytes
copying phaseroots
data fully migrated to temporary repository
marking source repository as being upgraded; clients will be unable to read from repository
starting in-place swap of repository data
replaced files will be backed up at $TESTTMP/upgradegd/.hg/upgradebackup.* (glob)
replacing store...
store replacement complete; repository was inconsistent for *s (glob)
finalizing requirements file and making repository readable again
removing temporary repository $TESTTMP/upgradegd/.hg/upgrade.* (glob)
copy of old repository backed up at $TESTTMP/upgradegd/.hg/upgradebackup.* (glob)
the old repository will not be deleted; remove it to free up disk space once the upgraded repository is verified
Original requirements backed up
$ cat .hg/upgradebackup.*/requires
dotencode
fncache
revlogv1
store
generaldelta added to original requirements files
$ cat .hg/requires
dotencode
fncache
generaldelta
revlogv1
store
store directory has files we expect
$ ls .hg/store
00changelog.i
00manifest.i
data
fncache
phaseroots
undo
undo.backupfiles
undo.phaseroots
manifest should be generaldelta
$ hg debugrevlog -m | grep flags
flags : inline, generaldelta
verify should be happy
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
3 files, 3 changesets, 3 total revisions
old store should be backed up
$ ls .hg/upgradebackup.*/store
00changelog.i
00manifest.i
data
fncache
phaseroots
undo
undo.backup.fncache
undo.backupfiles
undo.phaseroots
$ cd ..
store files with special filenames aren't encoded during copy
$ hg init store-filenames
$ cd store-filenames
$ touch foo
$ hg -q commit -A -m initial
$ touch .hg/store/.XX_special_filename
$ hg debugupgraderepo --run
upgrade will perform the following actions:
requirements
preserved: dotencode, fncache, generaldelta, revlogv1, store
beginning upgrade...
repository locked and read-only
creating temporary repository to stage migrated data: $TESTTMP/store-filenames/.hg/upgrade.* (glob)
(it is safe to interrupt this process any time before data migration completes)
migrating 3 total revisions (1 in filelogs, 1 in manifests, 1 in changelog)
migrating 109 bytes in store; 107 bytes tracked data
migrating 1 filelogs containing 1 revisions (0 bytes in store; 0 bytes tracked data)
finished migrating 1 filelog revisions across 1 filelogs; change in size: 0 bytes
migrating 1 manifests containing 1 revisions (46 bytes in store; 45 bytes tracked data)
finished migrating 1 manifest revisions across 1 manifests; change in size: 0 bytes
migrating changelog containing 1 revisions (63 bytes in store; 62 bytes tracked data)
finished migrating 1 changelog revisions; change in size: 0 bytes
finished migrating 3 total revisions; total change in store size: 0 bytes
copying .XX_special_filename
copying phaseroots
data fully migrated to temporary repository
marking source repository as being upgraded; clients will be unable to read from repository
starting in-place swap of repository data
replaced files will be backed up at $TESTTMP/store-filenames/.hg/upgradebackup.* (glob)
replacing store...
store replacement complete; repository was inconsistent for *s (glob)
finalizing requirements file and making repository readable again
removing temporary repository $TESTTMP/store-filenames/.hg/upgrade.* (glob)
copy of old repository backed up at $TESTTMP/store-filenames/.hg/upgradebackup.* (glob)
the old repository will not be deleted; remove it to free up disk space once the upgraded repository is verified
$ cd ..