This commit adds a markdown document which explains how the
thread-local VM infrastructure works, in case it is useful in the
future.
Change-Id: Id10e32a9e3c5fa38a15d4bec9800f7234c59234a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7193
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
This implements builtins.split, and passes eval-okay-regex-split.nix
(which is moved out of notyetpassing).
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: Ieb0975da2058966c697ee0e2f5b3f26ccabfae57
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7143
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
We're getting close to the finish line, folks.
I went through the list of builtins and there are only 33 that
remain unimplemented. I've marked them, and indicated which are
ready to be implemented vs which are waiting for other things.
We can delete this column from the table once everything is
implemented.
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: Idfaef93283536288b12e59aef5c3e1cd139bd133
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7140
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
I believe that the currentTime, findFile, hashFile, pathExists,
readDir, path (unless ?sha256), and readFile builtins are impure.
This commit marks them as such in docs/builtins.md.
Change-Id: Ib1b59fe643dde73cb2b00050b4ef9d3401ad22eb
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7139
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Working on https://github.com/NixOS/nix/pull/7158, I discovered that C++
Nix actually is strict in the accumulator, just not in the first value.
This seems due to the fact that in the C++ evaluator, function calls
don't seem to be thunked unconditionally and foldl' just elects not to
wrap it in a thunk (don't quote me on this summary, even though it seems
to line up with the code for primop_foldlStrict and testable behavior).
It doesn't seem worth it to risk breaking the odd Nix expression just to
be strict in one more value per invocation of foldl' (i.e. the initial
accumulator value `nul`), so let's match the existing C++ Nix behavior
here.
Change-Id: If59e62271a90d97cb440f0ca72a58ec7840d1690
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7022
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
When investigating discrepancies between foldl' in tvix and C++ Nix,
I discovered that C++ Nix's foldl' doesn't seem to be strict at all.
Since this seemed wrong, I looked into Haskell's foldl' implementation
which doesn't force the list elements (`val` in our code), but the
accumulation value (`res` in our code). You can look at the code here:
https://hackage.haskell.org/package/base-4.17.0.0/docs/src/GHC.List.html#foldl%27
This actually makes a lot of sense: If `res` is not forced after each
application of `op`, we'll end up thunks nested as deeply as the list is
long, potentially taking up a lot of space. This can be limited by
forcing the `res` thunk before applying `op` again (and creating a new
thunk).
I've also PR-ed an equivalent change for C++ Nix at
https://github.com/NixOS/nix/pull/7158. Since this is not merged nor
backported to our Nix 2.3 fork, I've not copied the eval fail test yet,
since it wouldn't when checking our tests against C++ Nix in depot.
Change-Id: I34edf6fc3031fc1485c3e714f2280b4fba8f004b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6947
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
The idea is that we can keep track of the more unexpected behavior,
behavior that maybe should not be a thing at all and behavior we are not
sure about yet.
Change-Id: I70933f00af1230a7ab9d30e917b61199fe571caf
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6803
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Just want to note those down somewhere before I forget them again,
we can delete them later if we have it all figured out.
Change-Id: Icafa2d8fc7ca39e38e9637b7eca6f2bbf487c2b8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6632
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Previously, "calling" (setting up the VM run loop for executing a call
frame) and "running" (running this loop to completion) were separate
operations.
This was basically an attempt to avoid nesting `VM::run` invocations.
However, doing things this way introduced some tricky bugs for exiting
out of the call frames of thunks vs. builtins & closures.
For now, we unify the two operations and always return the value to
the caller directly. For now this makes calls a little less effective,
but it gives us a chance to nail down some other strange behaviours
and then re-optimise this afterwards.
To make sure we tackle this again further down I've added it to the
list of known possible optimisations.
Change-Id: I96828ab6a628136e0bac1bf03555faa4e6b74ece
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6415
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
`builtins.getFlake` doesn't interest us, of course, but some others may
be worth (or easy) to implement. They are pretty low priority, though,
since nixpkgs has compatiblity wrappers for the ones it uses.
The new debugging-related builtins (break and traceVerbose) are
interesting to note, but may not make sense to implement at all.
Change-Id: Icae547aa3bd9d6ee6b87897ba8210eb9b9b044c7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6332
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
