Unconditionally close repository in unregisterAndCloseRepository
Repository.close() method is used when reference counting and expiration
needs to be honored. The RepositoryCache.unregisterAndCloseRepository
method should close the repository unconditionally. This is also indicated
from its javadoc.
Change-Id: I19392d1eaa17f27ae44b55eea49dcff05a52f298
Adds a JGit built-in implementation of the "git lfs smudge" filter. This
filter should do the same as the one described in [1] besides that it
only supports the local case when the lfs objects are already present in
the media directory. Remote cases where download of LFS objects from an
LFS server is needed will be done in a later commit.
[1] https://github.com/github/git-lfs/blob/master/docs/man/git-lfs-smudge.1.ronn
Change-Id: I8ff661d4edd3667ef7f86f3b4fa33e568eb4c8f4
Add configuration parameter to enable built-in hooks/filters
If the configuration parameter filter.<filterDriverName>.useJGitBuiltin
is set to true then for all corresponding filters JGit will try to
execute the built-in filter instead of the filter-command which is
defined in git configuration. It will fallback to the non-built-in
filters if no built-in filters are registered or if constructing them
leads to exceptions. If set to false JGit will not try to execute
built-in filters for the specified filter driver.
Example: The configuration contains the following lines
[filter "lfs"]
clean = git-lfs clean -- %f
smudge = git-lfs smudge -- %f
useJGitBuiltin = true
Addtionally the .gitattributes file in the root of the working tree
contains:
*.bin filter=lfs
In this case when new content is added similar to "git add 1.bin" then
the following will happen:
- jgit will check whether a built-in command factory was registered
for the command "jgit://builtin/lfs/clean". If that is true the
factory is used to create a built-in filter command and that
command is used to filter the content
- Otherwise jgit will call the external program "git lfs clean ..."
to do the filtering
Change-Id: Idadb1db06b1e89e7031d7ed6319904973c367d38
JGit supports smudge filters defined in repository configuration. The
filters are implemented as external programs filtering content by
accepting the original content (as seen in git's object database) on
stdin and which emit the filtered content on stdout. This content is
then written to the file in the working tree. To run such a filter JGit
has to start an external process and pump data into/from this process.
This commit adds support for built-in smudge filters which are
implemented in Java and which are executed by jgit's main thread. When a
filter is defined in the configuration as
"jgit://builtin/<filterDriverName>/smudge" then JGit will lookup in a
static map whether a builtin filter is registered under this name. If
found such a filter is called to do the filtering.
The functionality in this commit requires that a program using JGit
explicitly calls the JGit API to register built-in implementations for
specific smudge filters. In follow-up commits configuration parameters
will be added which trigger such registrations.
Change-Id: Ia743aa0dbed795e71e5792f35ae55660e0eb3c24
JGit supports clean filters defined in repository configuration. The
filters are implemented as external programs filtering content by
accepting the original content (as seen in the working tree) on stdin
and which emit the filtered content on stdout. To run such a filter JGit
has to start an external process and pump data into/from this process.
This commit adds support for clean filters which are implemented
in Java and which are executed by jgit's main thread. When a filter is
defined in the configuration as
"jgit://builtin/<filterDriverName>/clean" then JGit will lookup in a
static map whether a filter is registered under this name. If found
such a filter is called to do the filtering.
The functionality in this commit requires that a program using JGit
explicitly calls the JGit API to register built-in implementations for
specific clean filters. In follow-up commits configuration parameters
will be added which trigger such registrations. Other commits will add
implementations for lfs filters.
Change-Id: I0344d3c54801c9a46e5a606c5df17e5f2e17b2be
This is like PackStatistics, but for PackParser.
Change-Id: I854215c0956fd0b36843d631780be303e021b8be
Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>
BranchConfig treated this config property as a boolean, but git also
allows the values "preserve" and "interactive". Config property
pull.rebase also allows the same values.
Replace private enum PullCommand.PullRebaseMode by new public enum
BranchConfig.BranchRebaseMode and adapt all uses. Add a new setter to
PullCommand.
Note: PullCommand will treat "interactive" like "true", i.e., as a
non-interactive rebase. Not sure how "interactive" should be handled.
At least it won't balk on it.
Bug: 499482
Change-Id: I7309360f5662b2c2efa1bd8ea6f112c63cf064af
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>
Change-Id: I6691b454404dd4db3c690ecfc7515de765bc2ef7
Signed-off-by: Martin Goellnitz <m.goellnitz@outlook.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Don't log error if system git config does not exist
- enhance FS.readPipe to throw an exception if the external command
fails to enable the caller to handle the command failure
- reduce log level to warning if system git config does not exist
- improve log message
Bug: 476639
Change-Id: I94ae3caec22150dde81f1ea8e1e665df55290d42
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
ReceivePack: integrate push option parsing into recvCommands
This allows the same try/catch to handle parsing the command list,
push certificate and push options. Any errors will be caught and
handled by the same catch block, as the client is in the same state.
Change-Id: I13a66f9100e2dc8ca8f72cd701a5bd44d093ec84
Checking if the instance allows push options before returning the
collection or null is a bit overkill. Just return the collection
or return null.
Change-Id: Icdc3755194373966e5819284aeb9bfe8dd34de82
Some embeddings of JGit require creating a ReceivePack instance in
another process from the one that handled the network socket with the
client. Similar to the PushCertificate add a setter to allow the
option list to be supplied.
Change-Id: I303a30e54942ad067c79251eff8b53329c406628
Refactor all of the push option support code to allocate the list
immediately before parsing the options section off the stream.
Move option support down to ReceivePack instead of BaseReceivePack.
Push options are specific to the ReceivePack protocol and are not
likely to appear in the 4 year old subscription proposal. These
changes are OK before JGit 4.5 ships as no consumer should be relying
on these new APIs.
Change-Id: Ib07d18c877628aba07da07cd91875f918d509c49
Initialize pushOptions when we decide to use them, instead of when we
advertise them.
In the case of HTTP the advertisement is in a different network
request, hence in a different instance of the BaseReceivePack.
Change-Id: I094c60942e04de82cb6d8433c9cd43a46ffae332
Signed-off-by: Stefan Beller <sbeller@google.com>
Do not open an OBJ_TREE if the caller is expecting an OBJ_BLOB or
OBJ_COMMIT; instead throw IncorrectObjectTypeException. This better
matches behavior of WindowCursor, the ObjectReader implementation of
the local file based object store.
Change-Id: I3fb0e77f54895b123679a405e1b6ba5b95752ff0
Clarify the semantics of DfsRefDatabase#compareAndPut
DfsRefDatabase#compareAndPut had a vague semantics for reference
matching. Because of this, an operation to make a symbolic
reference had been broken for some DFS implementations even if they
followed the contract of compareAndPut. The clarified semantics
requires the implementations to satisfy the followings:
* Matching references should be both symbolic references or both
object ID references.
* If both are symbolic references, both should have the same target
name.
* If both are object ID references, both should have the same object
ID.
This semantics is defined based on
https://git.eclipse.org/r/#/c/77416/. Before this commit,
DfsRefDatabase couldn't see the target of symbolic references.
InMemoryRepository is changed to comply with the new semantics. This
semantics change can affect the existing DFS implementations that only
checks object IDs. This commit adds two tests that the previous
InMemoryRepository couldn't pass.
Change-Id: I6c6b5d3cc8241a81f4a37782381c88e8a59fdf15
Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>
When doing a detaching operation, JGit fakes a SymbolicRef as an
ObjectIdRef. This is because RefUpdate#updateImpl dereferences the
SymbolicRef when updating it. For example, assume that HEAD is
pointing to refs/heads/master. If I try to make a detached HEAD
pointing to a commit c0ffee, RefUpdate dereferences HEAD as
refs/heads/master first and changes refs/heads/master to c0ffee. The
detach argument of RefDatabase#newUpdate avoids this dereference by
faking HEAD as ObjectIdRef.
This faking is problematic for the linking operation of
DfsRefDatabase. It does a compare-and-swap operation on every
reference change because of its distributed systems nature. If a
SymbolicRef is faked as an ObjectRef, it thinks that there is a
racing change in the reference and rejects the update. Because of
this, DFS based repositories cannot change the link target of symbolic
refs. This has not been a problem for file-based repositories because
they have a file-lock based semantics instead of the CAS based one.
The reference implementation, InMemoryRepository, is not affected
because it only compares ObjectIds.
When [1] introduced this faking code, there was no way for RefUpdate
to distinguish the detaching operation. When [2] fixed the detaching
operation, it introduced a detachingSymbolicRef flag. This commit uses
this flag to control whether it needs to dereference the symbolic refs
by calling Ref#getLeaf. The same flag is used in the reflog update
operation.
This commit does not affect any operation that succeeds currently. In
some DFS repository implementations, this fixes a ref linking
operation, which is currently failing.
[1]: 01b5392cdb
[2]: 3a86868c08
Change-Id: I118f85f0414dbfad02250944e28d74dddd59469b
Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>
Imitate the packet tracing feature from C Git v1.7.5-rc0~58^2~1 (add
packet tracing debug code, 2011-02-24). Unlike C Git, use the log4j
log level setting instead of the GIT_TRACE_PACKET environment variable
to enable tracing.
Tested as follows:
1. Enable tracing by adding the lines
log4j.logger.org.eclipse.jgit.transport=DEBUG, stderr
log4j.additivity.org.eclipse.jgit.transport=false
to org.eclipse.jgit.pgm/resources/log4j.properties.
2. mvn package
3. org.eclipse.jgit.pgm/target/jgit \
ls-remote git://git.kernel.org/pub/scm/git/git 2>&1 |less
Then the output provides a trace of packets sent and received over
the wire:
2016-08-24 16:36:42 DEBUG PacketLineOut:145 - git> git-upload-pack /pub/scm/git/git^@host=git.kernel.org^@
2016-08-24 16:36:42 DEBUG PacketLineIn:165 - git< 2632c897f7 HEAD^@multi_ack thin-pack side-band side-band-64k ofs-delta shallow no-progress include-tag multi_ack_detailed symref=HEAD:refs/heads/master agent=git/2.8.4
2016-08-24 16:36:42 DEBUG PacketLineIn:165 - git< e0c1ceafc5 refs/heads/maint
Change-Id: I5028c064f3ac090510386057cb4e6d30d4eae232
Signed-off-by: Dan Wang <dwwang@google.com>
This fixes the tests failed in JDK8.
FS uses java.nio API to get file attributes. The timestamps obtained
from that API are more precise than the ones from
java.io.File#lastModified() since Java8.
This difference accidentally makes JGit detect newly added files as
smudged. Use the precised timestamp to avoid this false positive.
Bug: 500058
Change-Id: I9e587583c85cb6efa7562ad6c5f26577869a2e7c
Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>
Don't check lastModified, length on folders for submodules
The metadata comparison of submodules is not reliable because of the
last modified timestamp and directory length.
Bug: 498759
Change-Id: If5db69ef3868e475ac477d3e8a7750b268799b0c
Add HTTP status code to ServiceMayNotContinueException
The exception can be thrown in a various reason, and sometimes 403
Forbidden is not appropriate. Make the HTTP status code customizable.
Change-Id: If2ef6f454f7479158a4e28a12909837db483521c
Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>
AddCommandTest is flaky because IOException is thrown sometimes.
Caused by: java.io.IOException: Stream closed
at java.lang.ProcessBuilder$NullOutputStream.write(ProcessBuilder.java:433)
at java.io.OutputStream.write(OutputStream.java:116)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
at java.io.FilterOutputStream.close(FilterOutputStream.java:158)
at org.eclipse.jgit.util.FS.runProcess(FS.java:993)
at org.eclipse.jgit.util.FS.execute(FS.java:1102)
at org.eclipse.jgit.treewalk.WorkingTreeIterator.filterClean(WorkingTreeIterator.java:470)
... 22 more
OpenJDK replaces the underlying OutputStream with NullOutputStream when
the process exits. This throws IOException for all write operation. When
it exits before JGit writes the input to the pipe buffer, the input
stays in BufferedOutputStream. The close method tries to write it again,
and IOException is thrown.
Since we ignore IOException in StreamGobbler, we also ignore it when
we close the stream.
Fixes Bug 499633.
Change-Id: I30c7ac78e05b00bd0152f697848f4d17d53efd17
Signed-off-by: Masaya Suzuki <draftcode@gmail.com>
DfsObjDatabase: clear PackList dirty bit if no new packs
If a reference was updated more recently than a pack was written
(typical) the PackList was perpetually dirty until the next GC
was completed for the repository.
Detect this condition by observing no changes to the PackList
membership and resetting the dirty bit.
Change-Id: Ie2133aca1f8083307c73b6a26358175864f100ef
Enhance ResetCommand to allow disabling reflog update
This will be used by EGit for implementing commit amend in the staging
view (see Idcd1efeeee8b3065bae36e285bfc0af24ab1e88f).
Change-Id: Ice9ebbb1c0c3314c679f4db40cdd3664f61c27c3
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
RepoCommand: Avoid group lists shadowing groups strings
Reported-by: David Pursehouse <david.pursehouse@gmail.com>
Change-Id: I9e9b021d335bda4d58b6bcc30f59b81ac5b37724
Signed-off-by: Jonathan Nieder <jrn@google.com>
Shallow fetch: Pass along "shallow"s in unparsed-wants case, too
Since 84d2738ff2 (Don't skip want validation when the client sends no
haves, 2013-06-21), this branch is not taken. Process the
"shallow"s anyway as a defensive measure in case the code path gets
revived.
Change-Id: Idfb834825d77f51e17191c1635c9d78c78738cfd
Signed-off-by: Jonathan Nieder <jrn@google.com>
d385a7a5e5 (Shallow fetch: Respect "shallow" lines, 2016-08-03) forgot
that UploadPack wasn't passing a DepthWalk to PackWriter in the first
place. As a result, shallow clones fail:
java.lang.IllegalArgumentException: Shallow packs require a DepthWalk
at org.eclipse.jgit.internal.storage.pack.PackWriter.preparePack(PackWriter.java:756)
at org.eclipse.jgit.transport.UploadPack.sendPack(UploadPack.java:1497)
at org.eclipse.jgit.transport.UploadPack.sendPack(UploadPack.java:1381)
at org.eclipse.jgit.transport.UploadPack.service(UploadPack.java:774)
at org.eclipse.jgit.transport.UploadPack.upload(UploadPack.java:667)
at org.eclipse.jgit.http.server.UploadPackServlet.doPost(UploadPackServlet.java:191)
Change-Id: Ib0d8c2946eebfea910a2b767fb92e23da15d4749
Shallow fetch/clone: Make --depth mean the total history depth
cgit changed the --depth parameter to mean the total depth of history
rather than the depth of ancestors to be returned [1]. JGit still uses
the latter meaning, so update it to match cgit.
depth=0 still means a non-shallow clone. depth=1 now means only the
wants rather than the wants and their direct parents.
This is accomplished by changing the semantic meaning of "depth" in
UploadPack and PackWriter to mean the total depth of history desired,
while keeping "depth" in DepthWalk.{RevWalk,ObjectWalk} to mean
the depth of traversal. Thus UploadPack and PackWriter always
initialize their DepthWalks with "depth-1".
[1] upload-pack: fix off-by-one depth calculation in shallow clone
https://code.googlesource.com/git/+/682c7d2f1a2d1a5443777237450505738af2ff1a
Change-Id: I87ed3c0f56c37e3491e367a41f5e555c4207ff44
Signed-off-by: Terry Parker <tparker@google.com>
When fetching from a shallow clone, the client sends "have" lines
to tell the server about objects it already has and "shallow" lines
to tell where its local history terminates. In some circumstances,
the server fails to honor the shallow lines and fails to return
objects that the client needs.
UploadPack passes the "have" lines to PackWriter so PackWriter can
omit them from the generated pack. UploadPack processes "shallow"
lines by calling RevWalk.assumeShallow() with the set of shallow
commits. RevWalk creates and caches RevCommits for these shallow
commits, clearing out their parents. That way, walks correctly
terminate at the shallow commits instead of assuming the client has
history going back behind them. UploadPack converts its RevWalk to an
ObjectWalk, maintaining the cached RevCommits, and passes it to
PackWriter.
Unfortunately, to support shallow fetches the PackWriter does the
following:
if (shallowPack && !(walk instanceof DepthWalk.ObjectWalk))
walk = new DepthWalk.ObjectWalk(reader, depth);
That is, when the client sends a "deepen" line (fetch --depth=<n>)
and the caller has not passed in a DepthWalk.ObjectWalk, PackWriter
throws away the RevWalk that was passed in and makes a new one. The
cleared parent lists prepared by RevWalk.assumeShallow() are lost.
Fortunately UploadPack intends to pass in a DepthWalk.ObjectWalk.
It tries to create it by calling toObjectWalkWithSameObjects() on
a DepthWalk.RevWalk. But it doesn't work: because DepthWalk.RevWalk
does not override the standard RevWalk#toObjectWalkWithSameObjects
implementation, the result is a plain ObjectWalk instead of an
instance of DepthWalk.ObjectWalk.
The result is that the "shallow" information is thrown away and
objects reachable from the shallow commits can be omitted from the
pack sent when fetching with --depth from a shallow clone.
Multiple factors collude to limit the circumstances under which this
bug can be observed:
1. Commits with depth != 0 don't enter DepthGenerator's pending queue.
That means a "have" cannot have any effect on DepthGenerator unless
it is also a "want".
2. DepthGenerator#next() doesn't call carryFlagsImpl(), so the
uninteresting flag is not propagated to ancestors there even if a
"have" is also a "want".
3. JGit treats a depth of 1 as "1 past the wants".
Because of (2), the only place the UNINTERESTING flag can leak to a
shallow commit's parents is in the carryFlags() call from
markUninteresting(). carryFlags() only traverses commits that have
already been parsed: commits yet to be parsed are supposed to inherit
correct flags from their parent in PendingGenerator#next (which
doesn't happen here --- that is (2)). So the list of commits that have
already been parsed becomes relevant.
When we hit the markUninteresting() call, all "want"s, "have"s, and
commits to be unshallowed have been parsed. carryFlags() only
affects the parsed commits. If the "want" is a direct parent of a
"have", then it carryFlags() marks it as uninteresting. If the "have"
was also a "shallow", then its parent pointer should have been null
and the "want" shouldn't have been marked, so we see the bug. If the
"want" is a more distant ancestor then (2) keeps the uninteresting
state from propagating to the "want" and we don't see the bug. If the
"shallow" is not also a "have" then the shallow commit isn't parsed
so (2) keeps the uninteresting state from propagating to the "want
so we don't see the bug.
Here is a reproduction case (time flowing left to right, arrows
pointing to parents). "C" must be a commit that the client
reports as a "have" during negotiation. That can only happen if the
server reports it as an existing branch or tag in the first round of
negotiation:
A <-- B <-- C <-- D
First do
git clone --depth 1 <repo>
which yields D as a "have" and C as a "shallow" commit. Then try
git fetch --depth 1 <repo> B:refs/heads/B
Negotiation sets up: have D, shallow C, have C, want B.
But due to this bug B is marked as uninteresting and is not sent.
Change-Id: I6e14b57b2f85e52d28cdcf356df647870f475440
Signed-off-by: Terry Parker <tparker@google.com>
DepthWalk needs to override toObjectWalkWithSameObjects() and thus
needs to be able to directly set the objects and freeFlags fields, so
make them package private.
Change-Id: I24561b82c54ba3d6522582ca25105b204d777074
Signed-off-by: Terry Parker <tparker@google.com>
When doing an incremental fetch from JGit, "have" commits are marked
as "uninteresting". In a non-shallow fetch, when the RevWalk hits an
"uninteresting" commit it marks the commit's corresponding tree as
uninteresting. That has the effect of dropping those trees and all the
trees and blobs they reference out of the thin pack returned to the
client.
However, shallow fetches use a DepthWalk to limit the RevWalk, which
nearly always causes the RevWalk to terminate before encountering the
"have" commits. As a result the pack created for the incremental fetch
never encounters "uninteresting" tree objects and thus includes
duplicate objects that it knows the client already has.
Change-Id: I7b1f7c3b0d83e04d34cd2fa676f1ad4fec904c05
Signed-off-by: Terry Parker <tparker@google.com>
Skip cleaning inner repositories by default in CleanCommand
Previously jgit would attempt to clean git repositories that had not
been committed by calling a non-recursive delete on them, which would
fail as they are directories. This commit addresses that issue in the
following ways.
Repositories are skipped in a default clean, similarly to cgit and only
cleaned when the force flag is applied. When the force flag is applied
repositories are deleted using a recursive delete call. The force flag
and setForce method are added here to CleanCommand to support this
change.
Bug: 498367
Change-Id: Ib6cfff65a033d0d0f76395060bf76719e13fc467
Signed-off-by: Matthaus Owens <matthaus@puppetlabs.com>
We have to be able to access the enum from outside the package as part of
the API.
Change-Id: I4bdc6bd53a14237c5f4fb9397ae850f9a24c4cfb
Signed-off-by: Stefan Beller <sbeller@google.com>
Repository: Log negative useCnt message together with stack trace
The message "close() called when useCnt is already zero" is logged with
level warning, and then if debug logging is enabled, the stack trace is
logged separately with level debug.
Log the message and the stack trace in the same call, so that they always
appear together in the output rather than potentially interleaved with
other log statements.
Change-Id: I1b5c1557ddc2d19f3f5b29baec96e62bc467d88a
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
RefSpecs: allow construction of weird wildcarded RefSpecs
Gerrit's superproject subscription feature uses RefSpecs to formalize
the ACLs of when the superproject subscription feature is allowed.
As this is a slightly different use case than describing a local/remote
pair of refs, we need to be more permissive. Specifically we want to allow:
refs/heads/*
refs/heads/*:refs/heads/master
refs/heads/master:refs/heads/*
Introduce a new constructor, that allows constructing these RefSpecs.
Change-Id: I46c0bea9d876e61eb2c8d50f404b905792bc72b3
Signed-off-by: Stefan Beller <sbeller@google.com>
We had a case in Gerrits superproject subscriptions where
'refs/heads/' was configured with the intention to mean 'refs/heads/*'.
The first expression lacks the '*', which is why it is not considered
a wildcard but it was considered valid and so was not found early to be
a typo.
Refs are not allowed to end with '/' anyway, so add a check for that.
Change-Id: I3ffdd9002146382acafb4fbc310a64af4cc1b7a9
Signed-off-by: Stefan Beller <sbeller@google.com>
Example usage:
$ ./jgit push \
--push-option "Reviewer=j.doe@example.org" \
--push-option "<arbitrary string>" \
origin HEAD:refs/for/master
Stefan Beller has also made an equivalent change to CGit:
http://thread.gmane.org/gmane.comp.version-control.git/299872
Change-Id: I6797e50681054dce3bd179e80b731aef5e200d77
Signed-off-by: Dan Wang <dwwang@google.com>
DfsObjectDatabase: Expose PackList and move markDirty there
What's invalidated when an object database is "dirty" is not the whole
database, but rather a specific list of packs. If there is a race
between getting the pack list and setting the volatile dirty flag
where the packs are rescanned, we don't need to mark the new pack list
as dirty.
This is a fine point that only really applies if the decision of
whether or not to mark dirty actually requires introspecting the pack
list (say, its timestamps). The general operation of "take whatever
is the current pack list and mark it dirty" may still be inherently
racy, but the cost is not so high.
Change-Id: I159e9154bd8b2d348b4e383627a503e85462dcc6
This variable has been populated and never used since it was
introduced in commit 5cf53fdacf
(Speed up clone/fetch with large number of refs, 2013-02-18).
Noted by FindBugs:
"BatchRefUpdate.java:359, UC_USELESS_OBJECT, Priority: Normal"
Change-Id: I7aacb49540aaee4a83db3d38b15633bb6c4773d0
Signed-off-by: Dan Wang <dwwang@google.com>
Invalidate DfsObjDatabase pack list when refs are updated
Currently, there is a race where a user of a DfsRepository in a single
thread may get unexpected MissingObjectExceptions trying to look up an
object that appears as the current value of a ref:
1. Thread A scans packs before scanning refs, for example by reading
an object by SHA-1.
2. Thread B flushes an object and updates a ref to point to that
object.
3. Thread A looks up the ref updated in (2). Since it is scanning refs
for the first time, it sees the new object SHA-1.
4. Thread A tries to read the object it found in (3), using the cached
pack list it got from (1). The object appears missing.
Allow implementations to work around this by marking the object
database's current pack list as "dirty." A dirty pack list means that
DfsReader will rescan packs and try again if a requested object is
missing. Implementations should mark objects as dirty any time the ref
database reads or scans refs that might be newer than a previously
cached pack list.
Change-Id: I06c722b20c859ed1475628ec6a2f6d3d6d580700
Matthias Sohn
Saša Živkov
Christian Halstrick
Masaya Suzuki
Thomas Wolf
Andrey Loskutov
Martin Goellnitz
Shawn Pearce
Jonathan Nieder
Stefan Beller
Masaya Suzuki
Dan Wang
David Pursehouse
Terry Parker
Matthaus Owens
Dave Borowitz