jgit/org.eclipse.jgit.junit
Matthias Sohn b513b77477 Measure file timestamp resolution used in FileSnapshot
FileSnapshot.notRacyClean() assumed a worst case filesystem timestamp
resolution of 2.5 sec (FAT has a resolution of 2 sec). Instead measure
timestamp resolution to avoid unnecessary IO caused by false positives
in detecting the racy git problem caused by finite filesystem timestamp
resolution [1].

Cache the measured resolution per FileStore since timestamp resolution
depends on the respective filesystem type. If timestamp resolution
cannot be measured or fails due to an exception fallback to the worst
case FAT timestamp resolution and avoid caching this value.

Add a 10% safety margin in FileSnapshot.notRacyClean(), though running
FsTest.testFsTimestampResolution() 1000 times which is not using a
safety margin didn't fail on Mac using APFS and Java 8, 11, 12.

Measured Java file timestamp resolution: [2]

[1] https://github.com/git/git/blob/master/Documentation/technical/racy-git.txt
[2] https://docs.google.com/spreadsheets/d/1imy0y6WmRqBf0kjCxzxj2X7M50eIVfa7oaUIzEOHmjo

Bug: 546891
Change-Id: I493f3b57b6b306285ffa7d392339d253e5966ab8
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-05-22 08:13:22 +02:00
..
.settings Add API filter for "non-API type FileRepository" in tests 2018-05-06 01:25:26 +02:00
META-INF Prepare 5.1.8-SNAPSHOT builds 2019-04-20 10:51:17 +02:00
src/org/eclipse/jgit/junit Measure file timestamp resolution used in FileSnapshot 2019-05-22 08:13:22 +02:00
.classpath Change JGit minimum execution environment to JavaSE-1.8 2016-09-20 11:32:36 +02:00
.gitignore Finish removing Apache Felix maven-bundle-plugin 2010-01-12 11:46:55 -08:00
.project Enforce the use of Java5 API:s only (with a few exceptions) 2011-12-16 01:01:36 +01:00
BUILD Bazel: Restrict src globs to Java source files 2017-04-13 14:14:55 +09:00
build.properties Partial revert "Switch build to Apache Felix maven-bundle-plugin" 2010-01-10 15:59:03 +01:00
plugin.properties Fix plugin provider names to conform with release train requirement 2013-04-08 23:05:36 +02:00
pom.xml Prepare 5.1.8-SNAPSHOT builds 2019-04-20 10:51:17 +02:00