well, oops. on slow io (as can happen with ssh remote builders) we could
have extended a nar read buffer past what was actually read, injecting a
span of zeroes into the read buffer where we requested some data but got
a partial result instead. also add some tests that would've caught this.
Change-Id: I67aa06b4715aeec6a5bdacaafa9b79849e664e2f
there's no real usefulness to this output in build logs. in interactive
development builds -v can be passed to meson to restore the old output.
Change-Id: Iac4c0573fd1cac5fc9044b950ef52ee50448e6fc
connection pools of remote stores can currently block. this is not a
problem when each request runs on a dedicated thread, but with async
code this is no longer true. if a remote store has exhausted all its
available connections on one executor and another job starts *on the
same executor* we'll deadlock if that job makes another remote store
request. unlike with sqlite previously it's not reasonable, not even
necessary, to make the pools unbounded: since we use pools only with
remote stores we can asyncify all of them at once, and since they're
leaves of all call stacks we do not have much code to change either.
Change-Id: I8c457e27893e22c2cfc35933307a5283c986805a
sadly this is a visitor-only interface; async generators are not yet a
thing and preliminary benchmarks say that overhead would be too large.
Change-Id: I0460d18eba94441cf3101d46bfffdb69cdda81d1
we'll use this in NarAccessor to provide actually safe indexing of
archives. NarAccessor currently is not fully correct: it relies on
the parser not buffering anything to produce correct file offsets,
but only the nar implementation itself can reasonably expect that.
Change-Id: I64f300b86d8844b876a3ace723546ea7d7b4628b
this is where they should've been from the start, but during the first
rewrite it made little sense to move them. we have bigger plans today,
so we'll finally clean that up too. note the `Map` transform type that
is needed to make the current macros work. it shall be only temporary.
Change-Id: I928d197dbfe27b68cf8634d149c3259e86fbf123
This is kind of a painful change, because a lot of code grew around the
bad abstraction, but the goal here is to abstract formals in a way that
allows adding other means of pattern matching / argument destructuring
in the future.
Change-Id: If4e681a4be3d1f42ceea81a8e07297f0d08acc80
also mark the sync version as NeverAsync. a blocking wait on sqlite
locks in a coroutine may never finish if it's a different coroutine
on the same executor that is holding the lock, not another process.
this propagates to the sqlite core interface, but no further. we'll
assume that caches do not block on a database for very long, and we
can't reasonably propagate never-async-ness out of stores unless we
touch everything we'd touch for the async transition, again, twice.
store code already assumes that it can block for however long it'll
feel like that moment. we keep thread pools around for this reason.
Change-Id: I62f77e1ac333cbe2e4e646dbcb1571463f2cf3fc
4138fc7622 mistakenly removed an early
exit from non-main worker threads. this led to exceptions not ending
`process()` calls in a timely manner and instead draining the entire
work queue first, which for e.g. Interrupted errors would cause many
duplicated reports per worker thread instead of only one per thread.
it also did not properly rethrow a work item exception in all cases,
e.g. when all work had completed by the time `process()` was called.
due to a mistake in the thread starting check it was possible that a
system would require n² work items to start n worker threads if some
work items process quickly enough while other items block for a bit.
Change-Id: I7d59483580cda1c19980f9296074216a0fbf2c4e
We will link to boehm inside of the test suite if it depends on libexpr
but we don't need it for other tests.
For anything linking to libexpr internally, just like externally, it
needs to link to boehm.
Likewise with kj and libutil (or really any lix), so we should just make
it automatic.
Change-Id: I2bb9ec4668e6ff741b4139fdce167f278eb71c7e
ifd requires building which uses async code today, fetching requires
network io which really should use async code but does not yet. eval
itself cannot be made async for performance reasons. offloading work
to other threads is possible but questionable as currently there are
no uses in which evaluation must take place from within asynchronous
operations, which are currently confined entirely to store behavior.
Change-Id: I1e3c86fca19b042d79332e9a5ef9546f90a6448b
There's a race condition where awaitData could early-return for data
coming from a 404 response or similar and thus not rethrow the exception
that is forthcoming, and a related race during transfer setup (which
could retry a transfer *twice* per retry round).
This would then cause substitution failures like below since the exception
isn't caught in HttpBinaryCacheStore::getFile as intended, but instead
by an exception handler downstream of `drain()` which would error out
the entire operation.
Symptom:
» nix-build ./docs-service.nix -o "docs-service-result"
error: unable to download 'https://cache.nixos.org/7mr3fy8w66gi5inmf0jkkkl90lxy4jyg.narinfo': HTTP e
rror 404 ()
response body:
This is kind of a hack in how it is implemented: it assumes that you
can't intentionally be receiving a large unsuccessful response since in
such a case, `awaitData` will wait for finish() to be called to throw an
exception and will never escape until the download finishes, while
continuing to buffer the entire response into memory, which could be bad
if an error response had a large payload.
That said, nobody is sending Lix 1GiB of 404, so meh I guess, and this
is how it is seemingly intended to work. That was a design flaw of the
thing before any of the Lix team got our paws on it.
I tested this by adding _exit(0) inside the expected exception catch and
then running the offending command repeatedly to see if the symptom ever
appeared again, and it did not.
Needs cherry-pick to 2.92 and a 2.92.1 release once reviewed.
Fixes: https://git.lix.systems/lix-project/lix/issues/635
Co-Authored-By: lix@jade.fyi
Change-Id: If54f6eeaad60b5ca9d5b77d4d9232da1d295e7d1
The code for serialization Expr nodes back into (pseudo-)Nix has been
removed for being subtly error-prone and tedious to maintain. Instead,
`nix-instantiate --parse` now prints a JSON representation of the AST.
Usage patterns of the --parse flag I've found in the wild:
1. Check if a file is well-formed, i.e. discard output and test exit code
2. Get parser errors from a file, i.e. discard stdout and use stderr
3. Nixfmt uses --parse to test equivalence pre/post format, and that property is (should be?) preserved
None of these should break with the current change
Closes#487
Change-Id: Icdbaad17790f2ad8765fa08e02e6597ee4c7a909
references remain forbidden because std::optional does not want to
contain them, and specializing generators to use pointers where we
can't use optionals is simply too much work for a feature we don't
even need. reference wrappers and bindings still work well enough.
Change-Id: I2e6ca74719584ce16e2357c452fdd5c5a9e23d5a
in a daemon all calls to the logger can throw an Interrupted exception,
which so far has silently stopped the curl thread without notifying its
transfers and leaving them stuck as a result. ensuring that the loggers
can never throw Interrupted will have very unpleasant side-effects, and
throwing depending on context requires large amount of bookkeeping. for
now it is easiest to abort all transfers on Interrupted during cleanup.
the test for this is extremely sketchy because we want to hit a single,
very specifically chosen, loger call in TransferItem::finish(). the bug
was triggered by the `act.progress` further down from what we're aiming
for, but that one is much harder to select for than the debug log here.
fixes#613
Change-Id: Id72efa64dd30cbbf256d2ab2a328457a0b095c6a
After gathering more community feedback, more non-trivial use cases for
overriding `__findFile` emerged. Unlike the use case of Tvix mentioned
in #599, these can't easily be worked around by overriding `nixPath`
instead.
This is the second fixup/partial revert for
81d5f0a7d9.
See also #599.
Change-Id: I7ca75e1a2b196c0da341969c61f4c168b5f657f9
This is a useful piece of functionality to being able to eat URL
hyperlinks, for instance, which is a bug that Lix has while dealing with
terminal output today.
Change-Id: I77b2de107b2525cad7ea5dea28bfba2cc78b9e6d
I want this for being able to write reasonable expect-test style tests
for oneliners. We will still probably want something like insta for more
complicated test cases where you actually *want* the output in a
different file, but for now this will do.
cc: https://git.lix.systems/lix-project/lix/issues/595
Change-Id: I6ddc42963cc49177762cfca206fe9a9efe1ae65d
It being overridable was an intended feature with good use cases, and
should not have been removed. However, this feature is generally in a
bad state and needs revisiting in the future.
Fixup for 81d5f0a7d9Fixes#599
Change-Id: I2d93e012caa65aa795bce3a71d8e56d7052ef9df
The `show` functionality needs to be removed because it is deeply
flawed, and given that we already print position information in the
error message (which probably wasn't always the case in the past) the
assertion printing is redundant anyways.
Change-Id: I1f5e05ab73aaa0ec92994c2211463260fd374898
this finally gives us a witness type we can use to prove that a certain
call graph subtree can't be used in kj promises using only a single new
assumption: if EvalState& is never held as a reference member of a type
and instead only ever passes as an argument or held on the stack we can
be certain that anything that has access to en EvalState ref must never
be run inside a promise and, crucially, that anything that doesn't have
access to an EvalState& *can* be run inside a promise without problems.
Change-Id: I6c15ada479175ad7e6cd3e4a729a5586b3ba30d6
this is not necessary in any way, but it will make the following changes
smaller and easier to review. the aliases could also be added piecemeal,
but doing it here lets us lean heavily on our compilers for correctness.
(teacher notes: here the author foreshadows the shape of things to come.
not all names change, and only the names unchanged are those which will,
over time, become ever more unrecognizable. note especially nix/main.cc,
where `state` is not only cloned, but itself changes pointerness. it can
be seen as a nod to the trans community, but more realistically it is no
more than foreshadowing the future where `state` is only seen by proxy.)
Change-Id: I7732025e58df089b7f8e564fc63960cd91729d09
this will let us pass the capability to create debuggable eval errors
without having to pass an entire EvalState. we could pass symbols and
debug states around just as easily, but if we add new capabilities to
our debugger we might have to change many more places than with this.
Change-Id: I2f8893012e5d98a986ef1fc888234c2dd8d5e096
It was never intended to be a feature to be used, and moreover it is
inconsistent: One cannot override `+`, and overriding `__lessThan` won't
affect the builtins which do comparisons.
Change-Id: Iaba54a05aa4c2eb37cdb3dc0d731fcee5a86deba
eldritch horrors