This explicitly documents behavior of C++ Nix that goes against the
intuition you'd gather from this document: that e.g. a simple select
from an attribute set causes a value to no longer be pointer equal to
its former self.
The point of documenting this is that we can show in a to be written
section on the use of pointer equality in nixpkgs that pointer equality
is only needed in a limited sense for evaluating it (C++ Nix's exterior
pointer equality). Tvix's pointer equality is far more powerful since
value identity preserving operations also preserve pointer equality,
generally speaking (this is because we implement interior pointer
equality in my made up terminology). This should eventually also be
documented.
Change-Id: I6ce7ef2d67b012f5ebc92f9e81bba33fb9dce7d0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8856
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
This fixes a subtle issue which would occasionally lead to a crash (e.g.
when evaluating (pkgs.systemd.outPath with --trace-runtime): With each
character in the string that has a multi byte representation in UTF-8,
the actual byte position and what tvix thought it was would get out of
sync. This could either lead to
* Tvix swallowing characters or jumbling characters if multi byte
characters would cause the tracked index to become out of sync with
the byte position before the first character to be escaped, or
* Tvix crashing if (in the same situation) the out of sync index would
be within a UTF-8 byte sequence.
Luckily, std's `char_indices()` iterator implements exactly what
`nix_escape_char()`'s original author had in mind with
`.chars().enumerate()`. Using `i + 1` for continuing is safe, since all
characters that need (in fact, can) to be escaped in Nix are represented
as a single byte in UTF-8.
Change-Id: I1c836f70cde3d72db1c644e9112852f0d824715e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8952
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Improve change some little things I noticed while reading through it.
Change-Id: I033209eece395e5aad4e10825e8dd6c0cfe68191
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8725
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
I want to expand on the C++ Nix behavior, since it seems relevant to
note that a lot of operations in C++ Nix (like select) don't preserve
pointer equality (see
<https://github.com/NixOS/nix/issues/3371#issuecomment-1596167957>).
It is especially so, as Tvix establishes pointer equality in a different
way and thus shows differing behavior. Therefore I want to additionally
document Tvix's current behavior and make it more explicit to what
extent nixpkgs needs pointer equality.
Change-Id: I9b4ba75dacb749c9fcbba4b9646c6b48bb57bbad
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8852
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
This reverts commit f5e291cf83.
The offsets are relative to the start of the file, and as long as we
don't have BlobReaders implement seek, this will be very annoying to
deal with.
Change-Id: I05968f7c5c0ec0000597da90f451d6bb650c3e13
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8882
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
buf contains everything written so far, whereas b is the slice passed in
the current write() call. If we copy from &buf, we end up with the wrong
hash, because we keep writing the wrong data to the hash function.
Change-Id: I768d4645934a6a7d75b9c8eeba35f8f3be5edd26
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8880
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
This moves from stateless I/O to actually dealing with file handles,
allowing the filesystem to keep reusing existing blobreaders, instead of
opening a new reader on every read() call.
Change-Id: I3fc35c071e4aee1021c8bbd58749d082b0abd188
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8834
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>
The change allows applications that use tvix_serde for parsing
nix-based configuration to extend the language with domain-specific
set of features.
Change-Id: Ia86612308a167c456ecf03e93fe0fbae55b876a6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8848
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
I've noticed this behavior when writing the admittedly cursed test case
included in this CL. Alternatively we could use some sort of machinery
using `builtins.trace`, but I don't think we capture stderr anywhere.
I've elected to put this into the eval cache itself while C++ Nix does
it in builtins.import already, namely via `realisePath`. We don't have
an equivalent for this yet, since we don't support any kind of IfD, but
we could revise that later. In any case, it seems good to encapsulate
`ImportCache` in this way, as it'll also allow using file hashes as
identifiers, for example.
C++ Nix also does our equivalent of canon_path in `builtins.import`
which we still don't, but I suspect it hardly makes a difference.
Change-Id: I05004737ca2458a4c67359d9e7d9a2f2154a0a0f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8839
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This is a first implementation of a FUSE filesystem, mounting tvix-store
to a given location.
This is mostly meant as one additional lens into a store, and could be
used for builds. It's not meant to be used as a general-purpose thing.
It still has some rough edges:
- It doesn't implement open/close, so it doesn't use file handles.
Which means, we need to open blobs for partial reads over and over
again.
- It doesn't implement seek, as BlobReader doesn't implement seek yet.
- It doesn't track "lifetimes" of inodes by listening on forget,
meaning it might hold more data in memory than necessary.
- As we don't have store composition (and a caching layer) yet,
operations might be slow.
Change-Id: Ib1812ed761dfaf6aeb548443ae939c87530b7be8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8667
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>
When dealing with a formal argument in a function argument pattern that
has a default expression, there are two different things that can happen
at runtime: Either we select its value from the passed attribute
successfully or we need to use the default expression. Both of these may
be thunks and both of these may need finalisers. However, in the former
case this is taken care of elsewhere, the value will always be finalised
already if necessary. In the latter case we may need to finalise the
thunk resulting from the default expression. However, the thunk
corresponding to the expression may never end up in the local's stack
slot. Since finalisation goes by stack slot (and not constants), we need
to prevent a case where we don't fall back to the default expression,
but finalise anyways.
Previously, we worked around this by making `OpFinalise` ignore
non-thunks. Since finalisation of already evaluated thunks still
crashed, the faulty compilation of function pattern arguments could
still cause a crash.
As a new approach, we reinstate the old behavior of `OpFinalise` to
crash whenever encountering something that is either not a thunk or
doesn't need finalisation. This can also help catching (similar)
miscompilations in the future. To then prevent the crash, we need to
track whether we have fallen back or not at runtime. This is done using
an additional phantom on the stack that holds a new `FinaliseRequest`
value. When it comes to finalisation we check this value and
conditionally execute `OpFinalise` based on its value.
Resolves b/261 and b/265 (partially).
Change-Id: Ic04fb80ec671a2ba11fa645090769c335fb7f58b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8705
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
This adds a `from_str_with_config` function which takes a
user-supplied closure that sets additional settings on the
`tvix_eval::Evaluation`.
Note that users can not set `strict = false`, but other settings are
not restricted.
This solves b/262.
Change-Id: Ice184400b843cfbcaa5b6fe251ced12b6815e085
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8808
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Adds new tests for foldl', intersectAttrs as well as fills in missing
.exp files.
New test cases we don't pass:
- fromTOML timestamp capabilities
- path antiquotation
- replaceStrings is lazier on C++ Nix master
The C++ Nix revision used is 7066d21a0ddb421967980094222c4bc1f5a0f45a.
Change-Id: Ic619c96e2d41e6c5ea6fa93f9402b12e564af3c5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8778
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
genericClosure has very limited support for pointer equality: It relies
on comparison (not equality!) in C++ Nix, so as soon as C++ Nix supports
comparing lists (langVersion >= 6) we can rely on pointer equality for
key.
Since Tvix uses equality, not comparison for the insert, our behavior is
currently different, as documented by the notyetpassing tests.
Change-Id: Ifcd741ed4fc3ccc3825f7038875d56a9918b786a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8720
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
In order for the test suite we have currently to be comparable to C++
Nix, we need to display values in the same way. This was largely the
case except in some weird cases.
* <CODE> for thunks and <CYCLE> for repeated thunks (?) are already in
use. <CODE> formatting is tested by the oracle test suite already.
* Instead of lambda, we need to use <LAMBDA>
* <<primop>> and <<primop-app>> (a formatting C++ Nix uses nowhere)
now are <PRIMOP> and <PRIMOP-APP>.
We'll probably want to have a fancier display of values (in a separate
trait) down the line. This could be used for interactive usage, e.g. the
REPL or a potential debugger.
There is a peculiarity with C++ Nix 2.3 formatting primops: import is
considered a <<PRIMOP-APP>>, since it is internally implemented by means
of scopedImport. This implementation detail no longer leaks in C++ Nix
2.13 nor in Tvix.
<CYCLE> display is untested at the moment, since we exhibit a
discrepancy to C++ Nix 2.3. Our current detection is more similar to C++
Nix 2.13—luckily it is also the more consistent of the two. See also
b/245.
Change-Id: I1d534434b02e470bf5475b3758920ea81e3420dc
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8760
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
A previous iteration of this code did actually connect (in the gRPC
client), which was why we had this function async.
However, as the connection there is now lazy too, we can drop the
asyncness in this function.
Change-Id: Idd5bd953a6a1c2334066ee672cfb87fcb74f9f94
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8780
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This allows constructing blob stores with a URL syntax at runtime,
by passing the --blob-service-addr arg.
We probably still want to have some builder pattern here, to allow
additional schemes to be registered.
Change-Id: Ie588ff7a7c6fb64c9474dfbd2e4bc5f168dfd778
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8742
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
These were added by us in r/5276, so they should go into our test suite.
Change-Id: I6dc74fc242f33c22a17e0b4aee546ccae886ac85
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8774
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
C++ Nix resolves home relative paths at [parse] time. This is not an
option for us, since it prevents being able to separate the compilation
and execution phase later (e.g. precompiled nix expressions). However, a
practical consequence of this is that paths expressions are always
literals (strict) and never thunks.
[parse]: 7066d21a0d/src/libexpr/parser.y (L518-L527)
Change-Id: Ie4b9dc68f62c86d6c7fd5f1c9460c850d97ed1ca
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7041
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
There's very little reason to instantiate a GRPCPathInfoService in a
context where we are not already in a tokio context.
Change-Id: Ib81d649387717cb98de8a8039f92472f727b10c1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8755
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
The only place where we did use new was also already where we've been in
a tokio context, so just using from_client is easier.
Change-Id: I39dbc18f6aaa3abc342409be623395647f968530
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8754
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
There's very little reason to instantiate a GRPCBlobService in a context
where we are not already in a tokio context.
Change-Id: Ic6e18809a9f2a76f1c098ed330118d8dcfba5137
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8753
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
This removes the use of generics, like previously done with Blob and
Directory services.
Change-Id: I7cc8bd1439b026c88e80c11e38aafc63c74e5e84
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8751
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>
We never returned Err here anyways, and we can still return an error
during the first (or subsequent) write(s).
Change-Id: I4b4cd3d35f6ea008e9ffe2f7b71bfc9187309e2f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8750
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
From 64 bytes to 100 KBytes.
We need to provide a custom wrapper with a different Default instance.
Change-Id: Id7c6c437b8183b355a9e388f98cef1622b363f64
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8748
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
