Continuing along the same lines as commit
2739adc258, it seems that
while Remote -> Retriever expands to the same data type this changes
it to, ghc 9.0.1 refuses to consider them equiviant. I guess it has
something to do with the forall?
The rest of the build all succeeds, although the stack build then crashes:
Linking .stack-work/dist/x86_64-linux-tinfo6/Cabal-3.4.0.0/build/git-annex/git-annex ...
Completed 233 action(s).
Prelude.chr: bad argument: 2214592520
This issue seems likely to be about it:
https://github.com/commercialhaskell/stack/pull/5508
I'm building with stack from debian, version 2.3.3, so a newer stack
probably avoids that. Anyway, despite that stack problem,
the git-annex binary is built, and works.
The stack.yaml I used for this build was patched as follows:
diff --git a/stack.yaml b/stack.yaml
index 8dac87c15..62c4b5b9d 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,6 +1,6 @@
flags:
git-annex:
- production: true
+ production: false
assistant: true
pairing: true
torrentparser: true
@@ -14,7 +14,7 @@ flags:
httpclientrestricted: true
packages:
- '.'
-resolver: lts-18.13
+resolver: nightly-2021-09-07
extra-deps:
- IfElse-0.85
- aws-0.22
Sponsored-by: Graham Spencer on Patreon
This reverts commit 66b2536ea0.
I misunderstood commit ac56a5c2a0
and caused a FD leak when pid locking is not used.
A LockHandle contains an action that will close the underlying lock
file, and that action is run when it is closed. In the case of a shared
lock, the lock file is opened once for each LockHandle, and only
the one for the LockHandle that is being closed will be closed.
Seem there are several races that happen when 2 threads run PidLock.tryLock
at the same time. One involves checkSaneLock of the side lock file, which may
be deleted by another process that is dropping the lock, causing checkSaneLock
to fail. And even with the deletion disabled, it can still fail, Probably due
to linkToLock failing when a second thread overwrites the lock file.
The same can happen when 2 processes do, but then one process just fails
to take the lock, which is fine. But with 2 threads, some actions where failing
even though the process as a whole had the pid lock held.
Utility.LockPool.PidLock already maintains a STM lock, and since it uses
LockShared, 2 threads can hold the pidlock at the same time, and when
the first thread drops the lock, it will remain held by the second
thread, and so the pid lock file should not get deleted until the last
thread to hold it drops the lock. Which is the right behavior, and why a
LockShared STM lock is used in the first place.
The problem is that each time it takes the STM lock, it then also calls
PidLock.tryLock. So that was getting called repeatedly and concurrently.
Fixed by noticing when the shared lock is already held, and stop calling
PidLock.tryLock again, just use the pid lock that already exists then.
Also, LockFile.PidLock.tryLock was deleting the pid lock when it failed
to take the lock, which was entirely wrong. It should only drop the side
lock.
Sponsored-by: Dartmouth College's Datalad project
It ought to exist, since linkToLock has just created it. However,
Lustre seems to have a rather probabilisitic view of the contents of a
directory, so catching the error if it somehow does not exist and
running the same code path that would be ran if linkToLock failed
might avoid this fun Lustre failure.
Sponsored-by: Dartmouth College's Datalad project
Commit b6e4ed9aa7 made non-annexed files
be re-uploaded every time, since they're not tracked in the location log,
and it made it check the location log. Don't do that for non-annexed files.
Sponsored-by: Brock Spratlen on Patreon
