FS#getFileStoreAttributes used the real userConfig and not the mocked
one. This led to test errors when running tests with Bazel since it
sandboxes tests which prevents they can write to ~/.gitconfig.
Fix this by first preparing the MockedSystemReader and the mocked config
before calling FS#getFileStoreAttributes.
Also fix ConfigTest which broke due to this change since it inherits
from LocalDiskRepositoryTestCase and calls its setup method which was
changed here. We can no longer assert by comparing plain text since FS
adds FileStoreAttributes to the mocked userConfig. Also the default
options seen by this test changed since we now use a mocked config.
Change-Id: I76bc7c94953fe979266147d3b309a68dda9d4dfe
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
If we use the default system reader FileStoreAttributes cannot persist
attributes in userConfig when tests run in Bazel due to sandboxing.
Hence we need to ensure that all tests use MockSystemReader (and
especially a mocked userConfig).
Change-Id: Ic1ad8e2ec5a150c5433434a5f6667d6c4674c87d
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
This ensures we don't try to persist MockConfig using its superclasses
save() method which fails with an NPE since MockConfig has no backing
file.
Change-Id: Ifba2d24c9438bb30d3828ed31a4c131f940b45eb
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
We can't add this method to the super class StoredConfig since that
abstracts from filesystem storage. MockSystemReader.MockConfig is a
StoredConfig and is also used by tests for dfs based storage. Hence
remove this leaky abstraction.
This implies we always use the fallback FileStoreAttributes which means
a config file modification is considered racy within the first 2
seconds. This should not be an issue since typically configs change
rarely and re-reading a config within the racy period is relatively
cheap since configs are small.
Change-Id: Ia2615addc24a7cadf3c566ee842c6f4f07e159a5
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
This was enabled unintentionally in 06fc6c7c and spams the test logs. We
can enable this when needed.
Change-Id: I9f3042c0e285ff236be65fcc02bdcfdb90efc3af
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
- use slf4j-simple for logging in test runs
- for log configuration see
https://www.slf4j.org/api/org/slf4j/impl/SimpleLogger.html
Change-Id: I9f0a532644b31162c867cd0d63f083296eaf6be5
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Follow best practice in Eclipse OSGi based projects to export all
packages to foster reuse and experimentation.
Change-Id: I27f2810fbf0439fcb7c907e7b4d570a9613f8aa6
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Configure PDE to not warn about not exported packages for test bundles.
Reusable test code which other bundles may want to reuse should go into
one of the junit bundles:
- org.eclipse.jgit.junit
- org.eclipse.jgit.junit.http
- org.eclipse.jgit.junit.ssh
Change-Id: Ifbdf30f8552e8f4bad6bbdeb63f729c53c844315
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
All instances of this problem have been fixed. Increase its severity
to ERROR to prevent reoccurrences.
Change-Id: I42d41a7c32b43d1ba59a28cd2f5a7d0ad315d8d9
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
Move the implementation of the static equals() method to a new method
and suppress the error. Deprecate the old method to signal that we
intend to remove it in the next major release.
See https://errorprone.info/bugpattern/AmbiguousMethodReference
Change-Id: I712697a411ab44c6e05ae4604eb2dcb9c0f8abd3
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
Comparing with UTF_8 constant in StandardCharsets doesn't require to use
equals.
Change-Id: I6c73a929367f32c9e76ce99f6c0af268480d9230
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
It's not important to update time field, scalability is more important
than perfect LRU ordering of cache entries.
Change-Id: I22466c580cd3613b81e1989130b2724af9d6c466
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Implement a helper method suppressing the ReferenceEquality error prone
warning and use it to fix this warning in static equals methods where
this comparison is used to implement fast path of static equals
implementation.
See https://errorprone.info/bugpattern/ReferenceEquality
Change-Id: I33538a3406007d24efec3a504e031ca1069572ed
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Move the implementation of the static equals() method to a new method
and suppress the error. Deprecate the old method to signal that we
intend to remove it in the next major release.
See https://errorprone.info/bugpattern/AmbiguousMethodReference
Change-Id: I5e29c97f4db3e11770be589a6ccd785e2c9ac7f2
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Error Prone reports:
[ReferenceEquality] Comparison using reference equality instead of
value equality
The END_EDIT instance is used as a marker, and thus it's OK to use
a reference equality comparison. Factor the comparison to a method
and add a suppression.
Change-Id: I7d9dc1fa21f46c984787056b0b5d163e313026a6
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
Error Prone reports:
[NarrowingCompoundAssignment] Compound assignments from long to int
hide lossy casts
and
[NarrowingCompoundAssignment] Compound assignments from int to byte
hide lossy casts
See https://errorprone.info/bugpattern/NarrowingCompoundAssignment
Fix the warnings by adding explicit casts or changing types as
necessary.
Now that all occurrences of the warning are fixed, increase its
severity to ERROR.
Change-Id: Idb3670e6047b146ae37daee07212ff9455512623
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
Android unconditionally throws a SecurityException;[1] getFileStore()
is not supported. Catch the exception and don't attempt the hard-
linking atomic file mechanism.
[1] https://android.googlesource.com/platform/libcore/+/21e6175e25
Bug: 548947
Change-Id: Idfba2d9dbcbc80ea15ab2ae7889e5142444c1581
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>
* stable-5.3:
Fix OpenSshConfigTest#config
FileSnapshot: fix bug with timestamp thresholding
In LockFile#waitForStatChange wait in units of file time resolution
Cache FileStoreAttributeCache per directory
Fix FileSnapshot#save(long) and FileSnapshot#save(Instant)
Persist minimal racy threshold and allow manual configuration
Measure minimum racy interval to auto-configure FileSnapshot
Reuse FileUtils to recursively delete files created by tests
Fix FileAttributeCache.toString()
Add test for racy git detection in FileSnapshot
Repeat RefDirectoryTest.testGetRef_DiscoversModifiedLoose 100 times
Fix org.eclipse.jdt.core.prefs of org.eclipse.jgit.junit
Add missing javadoc in org.eclipse.jgit.junit
Enhance RepeatRule to report number of failures at the end
Fix FileSnapshotTests for filesystem with high timestamp resolution
Retry deleting test files in FileBasedConfigTest
Measure filesystem timestamp resolution already in test setup
Refactor FileSnapshotTest to use NIO APIs
Measure stored timestamp resolution instead of time to touch file
Handle CancellationException in FileStoreAttributeCache
Fix FileSnapshot#saveNoConfig
Use Instant for smudge time in DirCache and DirCacheEntry
Use Instant instead of milliseconds for filesystem timestamp handling
Workaround SecurityException in FS#getFsTimestampResolution
Fix NPE in FS$FileStoreAttributeCache.getFsTimestampResolution
FS: ignore AccessDeniedException when measuring timestamp resolution
Add debug trace for FileSnapshot
Use FileChannel.open to touch file and set mtime to now
Persist filesystem timestamp resolution and allow manual configuration
Increase bazel timeout for long running tests
Bazel: Fix lint warning flagged by buildifier
Update bazlets to latest version
Bazel: Add missing dependencies for ArchiveCommandTest
Bazel: Remove FileTreeIteratorWithTimeControl from BUILD file
Add support for nanoseconds and microseconds for Config#getTimeUnit
Optionally measure filesystem timestamp resolution asynchronously
Delete unused FileTreeIteratorWithTimeControl
FileSnapshot#equals: consider UNKNOWN_SIZE
Timeout measuring file timestamp resolution after 2 seconds
Fix RacyGitTests#testRacyGitDetection
Change RacyGitTests to create a racy git situation in a stable way
Deprecate Constants.CHARACTER_ENCODING in favor of StandardCharsets.UTF_8
Fix non-deterministic hash of archives created by ArchiveCommand
Update Maven plugins ecj, plexus, error-prone
Update Maven plugins and cleanup Maven warnings
Make inner classes static where possible
Fix API problem filters
Change-Id: Iec3ad6ccc194582cb844310dc172c3103dae4457
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
* stable-5.2:
Fix OpenSshConfigTest#config
FileSnapshot: fix bug with timestamp thresholding
In LockFile#waitForStatChange wait in units of file time resolution
Cache FileStoreAttributeCache per directory
Fix FileSnapshot#save(long) and FileSnapshot#save(Instant)
Persist minimal racy threshold and allow manual configuration
Measure minimum racy interval to auto-configure FileSnapshot
Reuse FileUtils to recursively delete files created by tests
Fix FileAttributeCache.toString()
Add test for racy git detection in FileSnapshot
Repeat RefDirectoryTest.testGetRef_DiscoversModifiedLoose 100 times
Fix org.eclipse.jdt.core.prefs of org.eclipse.jgit.junit
Add missing javadoc in org.eclipse.jgit.junit
Enhance RepeatRule to report number of failures at the end
Fix FileSnapshotTests for filesystem with high timestamp resolution
Retry deleting test files in FileBasedConfigTest
Measure filesystem timestamp resolution already in test setup
Refactor FileSnapshotTest to use NIO APIs
Measure stored timestamp resolution instead of time to touch file
Handle CancellationException in FileStoreAttributeCache
Fix FileSnapshot#saveNoConfig
Use Instant for smudge time in DirCache and DirCacheEntry
Use Instant instead of milliseconds for filesystem timestamp handling
Workaround SecurityException in FS#getFsTimestampResolution
Fix NPE in FS$FileStoreAttributeCache.getFsTimestampResolution
FS: ignore AccessDeniedException when measuring timestamp resolution
Add debug trace for FileSnapshot
Use FileChannel.open to touch file and set mtime to now
Persist filesystem timestamp resolution and allow manual configuration
Increase bazel timeout for long running tests
Bazel: Fix lint warning flagged by buildifier
Update bazlets to latest version
Bazel: Add missing dependencies for ArchiveCommandTest
Bazel: Remove FileTreeIteratorWithTimeControl from BUILD file
Add support for nanoseconds and microseconds for Config#getTimeUnit
Optionally measure filesystem timestamp resolution asynchronously
Delete unused FileTreeIteratorWithTimeControl
FileSnapshot#equals: consider UNKNOWN_SIZE
Timeout measuring file timestamp resolution after 2 seconds
Fix RacyGitTests#testRacyGitDetection
Change RacyGitTests to create a racy git situation in a stable way
Deprecate Constants.CHARACTER_ENCODING in favor of
StandardCharsets.UTF_8
Fix non-deterministic hash of archives created by ArchiveCommand
Update Maven plugins ecj, plexus, error-prone
Update Maven plugins and cleanup Maven warnings
Make inner classes static where possible
Fix API problem filters
Change-Id: I238adfd3080a5fed9d64c3c757297da6ea893918
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
* stable-5.1:
Fix OpenSshConfigTest#config
FileSnapshot: fix bug with timestamp thresholding
In LockFile#waitForStatChange wait in units of file time resolution
Cache FileStoreAttributeCache per directory
Fix FileSnapshot#save(long) and FileSnapshot#save(Instant)
Persist minimal racy threshold and allow manual configuration
Measure minimum racy interval to auto-configure FileSnapshot
Reuse FileUtils to recursively delete files created by tests
Fix FileAttributeCache.toString()
Add test for racy git detection in FileSnapshot
Repeat RefDirectoryTest.testGetRef_DiscoversModifiedLoose 100 times
Fix org.eclipse.jdt.core.prefs of org.eclipse.jgit.junit
Add missing javadoc in org.eclipse.jgit.junit
Enhance RepeatRule to report number of failures at the end
Fix FileSnapshotTests for filesystem with high timestamp resolution
Retry deleting test files in FileBasedConfigTest
Measure filesystem timestamp resolution already in test setup
Refactor FileSnapshotTest to use NIO APIs
Measure stored timestamp resolution instead of time to touch file
Handle CancellationException in FileStoreAttributeCache
Fix FileSnapshot#saveNoConfig
Use Instant for smudge time in DirCache and DirCacheEntry
Use Instant instead of milliseconds for filesystem timestamp handling
Workaround SecurityException in FS#getFsTimestampResolution
Fix NPE in FS$FileStoreAttributeCache.getFsTimestampResolution
FS: ignore AccessDeniedException when measuring timestamp resolution
Add debug trace for FileSnapshot
Use FileChannel.open to touch file and set mtime to now
Persist filesystem timestamp resolution and allow manual configuration
Increase bazel timeout for long running tests
Bazel: Fix lint warning flagged by buildifier
Update bazlets to latest version
Bazel: Add missing dependencies for ArchiveCommandTest
Bazel: Remove FileTreeIteratorWithTimeControl from BUILD file
Add support for nanoseconds and microseconds for Config#getTimeUnit
Optionally measure filesystem timestamp resolution asynchronously
Delete unused FileTreeIteratorWithTimeControl
FileSnapshot#equals: consider UNKNOWN_SIZE
Timeout measuring file timestamp resolution after 2 seconds
Fix RacyGitTests#testRacyGitDetection
Change RacyGitTests to create a racy git situation in a stable way
Deprecate Constants.CHARACTER_ENCODING in favor of StandardCharsets.UTF_8
Fix non-deterministic hash of archives created by ArchiveCommand
Update Maven plugins ecj, plexus, error-prone
Update Maven plugins and cleanup Maven warnings
Make inner classes static where possible
Fix API problem filters
Change-Id: Ia57385b2a60f48a5317c8d723721c235d7043a84
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
- use FS.DETECTED instead of db.getFS() since the ssh config is
typically in a different place than the repository, the same is used in
OpenSshConfig
- reduce unnecessary repeated writes by introducing wait for one tick of
the file time resolution
Change-Id: Ifac915e97ff420ec5cf8e2f162e351f9f51b6b14
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Increase the safety factor to 2.5x for extra safety if max of measured
timestamp resolution and measured minimal racy threshold is < 100ms, use
1.25 otherwise since for large filesystem resolution values the
influence of finite resolution of the system clock should be negligible.
Before, not yet using the newly introduced minRacyThreshold measurement,
the threshold was 1.1x FS resolution, and we could issue the
following sequence of events,
start
create-file
read-file (currentTime)
end
which had the following timestamps:
create-file 1564589081998
start 1564589082002
read 1564589082003
end 1564589082004
In this case, the difference between create-file and read is 5ms,
which exceeded the 4ms FS resolution, even though the events together
took just 2ms of runtime.
Reproduce with:
bazel test --runs_per_test=100 \
//org.eclipse.jgit.test:org_eclipse_jgit_internal_storage_file_FileSnapshotTest
The file system timestamp resolution is 4ms in this case.
This code assumes that the kernel and the JVM use the same clock that
is synchronized with the file system clock. This seems plausible,
given the resolution of System.currentTimeMillis() and the latency for
a gettimeofday system call (typically ~1us), but it would be good to
justify this with specifications.
Also cover a source of flakiness: if the test runs under extreme load,
then we could have
start
create-file
<long delay>
read
end
which would register as an unmodified file. Avoid this by skipping the
test if end-start is too big.
[msohn]:
- downported from master to stable-5.1
- skip test if resolution is below 10ms
- adjust safety factor to 1.25 for resolutions above 100ms
Change-Id: I87d2cf035e01c44b7ba8364c410a860aa8e312ef
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Since we now measure file time resolution we can use it to replace the
hard coded wait time of 25ms. FileSnapshot#equals will return true until
the mtime of the old (o) and the new FileSnapshot (n) differ by at least
one file time resolution.
Change-Id: Icb713a80ce9eb929242ed083406bfb6650c72223
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Cache FileStoreAttributeCache entries since looking up FileStore for a
file may be expensive on some platforms.
Implement a simple LRU cache based on ConcurrentHashMap using a simple
long counter to order access to cache entries.
Change-Id: I4881fa938ad2f17712c05da857838073a2fc4ddb
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Marc Strapetz <marc.strapetz@syntevo.com>
Also-By: Marc Strapetz <marc.strapetz@syntevo.com>
Use the fallback timestamp resolution as already described in the
javadoc of these methods. Using zero file timestamp resolution doesn't
make sense.
Change-Id: Iaad2a0f99c3be3678e94980a0a368181b6aed38c
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
To enable persisting the minimal racy threshold per FileStore add a
new config option to the user global git configuration:
- Config section is "filesystem"
- Config subsection is concatenation of
- Java vendor (system property "java.vendor")
- Java version (system property "java.version")
- FileStore's name, on Windows we use the attribute volume:vsn instead
since the name is not necessarily unique.
- separated by '|'
e.g.
"AdoptOpenJDK|1.8.0_212-b03|/dev/disk1s1"
The same prefix is used as for filesystem timestamp resolution, so
both values are stored in the same config section
- The config key for minmal racy threshold is "minRacyThreshold" as a
time value, supported time units are those supported by
DefaultTypedConfigGetter#getTimeUnit
- measure for 3 seconds to limit runtime which depends on hardware, OS
and Java version being used
If the minimal racy threshold is configured for a given FileStore the
configured value is used instead of measuring it.
When the minimal racy threshold was measured it is persisted in the user
global git configuration.
Rename FileStoreAttributeCache to FileStoreAttributes since this class
is now declared public in order to enable exposing all attributes in one
object.
Example:
[filesystem "AdoptOpenJDK|11.0.3|/dev/disk1s1"]
timestampResolution = 7000 nanoseconds
minRacyThreshold = 3440 microseconds
Change-Id: I22195e488453aae8d011b0a8e3276fe3d99deaea
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Also-By: Marc Strapetz <marc.strapetz@syntevo.com>
By running FileSnapshotTest#detectFileModified we found that the sum of
measured filesystem timestamp resolution and measured clock resolution
may yield a too small interval after a file has been modified which we
need to consider racily clean. In our tests we didn't find this behavior
on all systems we tested on, e.g. on MacOS using APFS and Java 8 and 11
this effect was not observed.
On Linux (SLES 15, kernel 4.12.14-150.22-default) we collected the
following test results using Java 8 and 11:
In 23-98% of 10000 test runs (depending on filesystem type and Java
version) the test failed, which means the effective interval which needs
to be considered racily clean after a file was modified is larger than
the measured file timestamp resolution.
"delta" is the observed interval after a file has been modified but
FileSnapshot did not yet detect the modification:
"resolution" is the measured sum of file timestamp resolution and clock
resolution seen in Java.
Java version filesystem failures resolution min delta max delta
1.8.0_212-b04 btrfs 98.6% 1 ms 3.6 ms 6.6 ms
1.8.0_212-b04 ext4 82.6% 3 ms 1.1 ms 4.1 ms
1.8.0_212-b04 xfs 23.8% 4 ms 3.7 ms 3.9 ms
1.8.0_212-b04 zfs 23.1% 3 ms 4.8 ms 5.0 ms
11.0.3+7 btrfs 98.1% 3 us 0.7 ms 4.7 ms
11.0.3+7 ext4 98.1% 6 us 0.7 ms 4.7 ms
11.0.3+7 xfs 98.5% 7 us 0.1 ms 8.0 ms
11.0.3+7 zfs 98.4% 7 us 0.7 ms 5.2 ms
Mac OS
1.8.0_212 APFS 0% 1 s
11.0.3+7 APFS 0% 6 us
The observed delta is not distributed according to a normal gaussian
distribution but rather random in the observed range between "min delta"
and "max delta".
Run this test after measuring file timestamp resolution in
FS.FileAttributeCache to auto-configure JGit since it's unclear what
mechanism is causing this effect.
In FileSnapshot#isRacyClean use the maximum of the measured timestamp
resolution and the measured "delta" as explained above to decide if a
given FileSnapshot is to be considered racily clean. Add a 30% safety
margin to ensure we are on the safe side.
Change-Id: I1c8bb59f6486f174b7bbdc63072777ddbe06694d
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Replace redundant complex implementation of recursive delete by the one
in FileUtils.
Change-Id: Iced1468b96c4f32381a9cf0c651b2bf6a9a9af35
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
We should not list the complete cache but only show the cache entry at
hand.
Change-Id: I22be2a4dcbf0145155e23f2389bfcf5662cf23a6
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Repeat the test 10000 times to get statistics if measured
fsTimestampResolution is working in practice to detect racy git
situations.
Add a class to compute statistics for this test. Log delta between
lastModified and time when FileSnapshot failed to detect modification.
This happens if the racy git limit determined by measuring filesystem
timestamp resolution and clock resolution is too small. If it would be
correct FileSnapshot would always detect modification or mark it
modified if time since modification is smaller than the racy git limit.
Change-Id: Iabe7af1a7211ca58480f8902d4fa4e366932fc77
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
This should help to detect if measured fsTimeResolution is too small.
Change-Id: Id1f54dbdedb52b17859904e47776fa3a5887b8be
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Use the same JDT core settings as used in org.eclipse.jgit but ignore
non-externalized strings.
Change-Id: If30013c76a197e571601a8abc882ac6a99592374
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
In order to enable counting how frequently a test fails if repeated add
option abortOnFailure. If it is true the test aborts on the first
failure. Otherwise it runs the configured number of repetitions and, if
there was any failure, throws a RepeatException reporting how many of
the test repetitions failed.
Change-Id: Ic47de44d4a6273fddf04b9993ad989903efb40c3
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
When filesystem timestamp resolution is very high some tests don't work
since runtime of the test setup is too long to reach a racily clean
FileSnapshot. Hence skip these tests when timestamp resolution is higher
than 10 millisecond.
Change-Id: Ie47dd10eda22037b5c1ebff6b6becce0654ea807
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
This helps to avoid some time critical tests can't prepare the test
fixture intended since measuring timestamp resolution takes time.
Change-Id: Ib34023e682a106070ca97e98ef16789a4dfb97b4
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
- use Path instead of File
- create test directories, files and output stream using Files methods
- delete unused list "files"
Change-Id: I8c5c601eca9f613efb5618d33b262277df92a06a
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Measure granularity of timestamps stored in the filesystem by setting
and then getting lastModified timestamp until the read value changed.
Increase increment exponentially to limit number of iterations starting
with 1 microsecond since Java's FileTime (up to Java 12) truncates
timestamps to 1 microsecond resolution. The chosen algorithm yields 2000
steps between 1 ms and 2.5 s.
Also measure clock resolution and add that for the total timestamp
resolution. This avoids systematic measurement errors introduced by
doing IO to touch a file.
Change-Id: I9b37138619422452373e298d9d8c7cb2c384db3f
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
We should not use configuration when creating FileSnapshot when
accessing FileBasedConfig.
Change-Id: Ic521632870f18bb004751642b9d30648dd94049a
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Matthias Sohn
David Pursehouse
Thomas Wolf
Han-Wen Nienhuys