Fix hang when transferring the same objects to two different clients at the
same time. (Or when annex.pidlock is used, two different objects to the
same or different clients.)
Could also potentially occur if a client was downloading an object and
somehow lost connection but that git-annex-shell was still running and
holding the transfer lock.
This does not guarantee that, if `transfer` fails for some other reason,
a DATA response will be made.
This work is supported by the NIH-funded NICEMAN (ReproNim TR&D3) project.
I suspect this may be due to SQLITE_IOERR_SHORT_READ, but have not
verified.
I was able to reproduce it on Linux after running the test suite in a loop
for 1-3 hours until it failed.
The WAL mode entry change in 3963c5fcf5
may have hidden the problem I was seeing; I have not seen an ErrorIO
since then.
This is safe, because while the annex object ends up executable,
there were already at least two other cases where it ended up executable:
1. git add an an executable file
2. chmod +x of a a non-executable worktree file that was hard linked to the
annex object
After copy/hard link, it always fixes up the permissions to match the mode
of the worktree file, so when an executable annex object gets hard linked
to a non-executable worktree file, its execute bit gets removed.
Commit b7c8bf5274 already *said* it would do
this; I suspect the line of code I've removed was included in that commit
accidentially.
Also improves annex.thin documentation.
This commit was sponsored by Boyd Stephen Smith Jr. on Patreon.
