* Merge branch 'stable-5.12'

* pgm: add missing dependency to org.apache.commons.logging

* Merge branch 'stable-5.9' into stable-5.10

* Prepare 5.7.1-SNAPSHOT builds

* Fix unclosed resource warning in SmartOutputStream
* JschConfigSessionFactory: fix boxing warning
* SshSupport#runSshCommand: don't throw exception in finally block
* Don't override already managed maven-compiler-plugin version
* Remove unused import from CreateFileSnapshotBenchmark
* Remove duplicate ignore_optional_problems entry in .classpath

* [error prone] Suppress NonAtomicVolatileUpdate in SimpleLruCache

* 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

* Silence API warnings for new API introduced for fixes

* Use SystemReader in JSchConfigSessionFactoryTest

* Update Eclipse Java compiler
* Update Jetty to 9.4.14

* Skip some tests when the runtime cannot handle Unicode file paths

* Add test for protocol v0 parser
* ObjectIdMatcher: Custom matcher for sets of ObjectIds

* Fix GC run in foreground to not use executor

* Fix comparison order in AnyObjectId

* reftable: reserve standard PackExt
* reftable: resolve symbolic references
* reftable: support threshold based compaction
* reftable: compact merged tables
* reftable: merge-join reftables
* reftable: lookup by ObjectId unit tests
* reftable: reflog unit tests
* reftable: namespace unit tests
* reftable: bulk operation unit tests
* reftable: basic functionality unit tests
* reftable: debug tools
* reftable: scan and lookup reftable files
* reftable: create and write reftable files
* reftable: file format documentation

* dfs: optionally store blockSize in DfsPackDescription

* Remove unnecessary @SuppressWarnings("nls")

* Follow redirects in transport

* pgm, test: Add missing dependency for buck build

* DirCacheCheckoutTest: Open Git and TreeWalk in try-with-resource
* CommitCommand: Remove declaration of unthrown exception
* Branch: Fix variable hiding warning
* ApplyCommandTest: Open Git in try-with-resource
* PackFileTest: Open ObjectInserter.Formatter in try-with-resource

* Rewrite push certificate parsing
* Allow trailing newlines in receive-pack

* Use try-with-resource to close resources in BundleWriter

* Fix unit tests for windows by explicitly closing test repos

* Fix DeltaTask infinite loop

* Remove duplicate package export

* ArchiveCommand: make archive formats non-inner classes

* Simplify size test in PackWriter
* Declare critical exposed methods of ObjectToPack final
* Declare internal flag accessors of ObjectToPack final
* Remove unused method isDeltaAttempted()
* Simplify setDoNotDelta() to always set the flag

* Refactored method to find branches from which a commit is reachable