Commit graph

32 commits

Author SHA1 Message Date
Robert Hensing
33d58a90c2 toJSON: Add attribute path to trace 2023-07-31 13:02:54 +02:00
Eelco Dolstra
01232358ff Merge remote-tracking branch 'origin/master' into source-path 2023-04-24 13:20:36 +02:00
John Ericson
85f0cdc370 Use std::set<StringContextElem> not PathSet for string contexts
Motivation

`PathSet` is not correct because string contexts have other forms
(`Built` and `DrvDeep`) that are not rendered as plain store paths.
Instead of wrongly using `PathSet`, or "stringly typed" using
`StringSet`, use `std::std<StringContextElem>`.

-----

In support of this change, `NixStringContext` is now defined as
`std::std<StringContextElem>` not `std:vector<StringContextElem>`. The
old definition was just used by a `getContext` method which was only
used by the eval cache. It can be deleted altogether since the types are
now unified and the preexisting `copyContext` function already suffices.

Summarizing the previous paragraph:

Old:

  - `value/context.hh`: `NixStringContext = std::vector<StringContextElem>`
  - `value.hh`: `NixStringContext Value::getContext(...)`
  - `value.hh`: `copyContext(...)`

New:

  - `value/context.hh`: `NixStringContext = std::set<StringContextElem>`
  - `value.hh`: `copyContext(...)`
----

The string representation of string context elements no longer contains
the store dir. The diff of `src/libexpr/tests/value/context.cc` should
make clear what the new representation is, so we recommend reviewing
that file first. This was done for two reasons:

Less API churn:

`Value::mkString` and friends did not take a `Store` before. But if
`NixStringContextElem::{parse, to_string}` *do* take a store (as they
did before), then we cannot have the `Value` functions use them (in
order to work with the fully-structured `NixStringContext`) without
adding that argument.

That would have been a lot of churn of threading the store, and this
diff is already large enough, so the easier and less invasive thing to
do was simply make the element `parse` and `to_string` functions not
take the `Store` reference, and the easiest way to do that was to simply
drop the store dir.

Space usage:

Dropping the `/nix/store/` (or similar) from the internal representation
will safe space in the heap of the Nix programming being interpreted. If
the heap contains many strings with non-trivial contexts, the saving
could add up to something significant.

----

The eval cache version is bumped.

The eval cache serialization uses `NixStringContextElem::{parse,
to_string}`, and since those functions are changed per the above, that
means the on-disk representation is also changed.

This is simply done by changing the name of the used for the eval cache
from `eval-cache-v4` to eval-cache-v5`.

----

To avoid some duplication `EvalCache::mkPathString` is added to abstract
over the simple case of turning a store path to a string with just that
string in the context.

Context

This PR picks up where #7543 left off. That one introduced the fully
structured `NixStringContextElem` data type, but kept `PathSet context`
as an awkward middle ground between internal `char[][]` interpreter heap
string contexts and `NixStringContext` fully parsed string contexts.

The infelicity of `PathSet context` was specifically called out during
Nix team group review, but it was agreeing that fixing it could be left
as future work. This is that future work.

A possible follow-up step would be to get rid of the `char[][]`
evaluator heap representation, too, but it is not yet clear how to do
that. To use `NixStringContextElem` there we would need to get the STL
containers to GC pointers in the GC build, and I am not sure how to do
that.

----

PR #7543 effectively is writing the inverse of a `mkPathString`,
`mkOutputString`, and one more such function for the `DrvDeep` case. I
would like that PR to have property tests ensuring it is actually the
inverse as expected.

This PR sets things up nicely so that reworking that PR to be in that
more elegant and better tested way is possible.

Co-authored-by: Théophane Hufschmitt <7226587+thufschmitt@users.noreply.github.com>
2023-04-21 01:05:49 -04:00
Eelco Dolstra
94812cca98 Backport SourcePath from the lazy-trees branch
This introduces the SourcePath type from lazy-trees as an abstraction
for accessing files from inputs that may not be materialized in the
real filesystem (e.g. Git repositories). Currently, however, it's just
a wrapper around CanonPath, so it shouldn't change any behaviour. (On
lazy-trees, SourcePath is a <InputAccessor, CanonPath> tuple.)
2023-04-06 13:15:50 +02:00
Eelco Dolstra
bda879170f EvalState::copyPathToStore(): Return a StorePath 2022-12-20 14:58:39 +01:00
Yorick van Pelt
09f00dd4d0
Replace src/libutil/json.cc with nlohmann json generation 2022-11-16 16:50:50 +01:00
Naïm Favier
062e4fcdde
JSON: print paths as strings without copying them to the store
Makes `printValueAsJSON` not copy paths to the store for `nix eval
--json`, `nix-instantiate --eval --json` and `nix-env --json`.

Fixes https://github.com/NixOS/nix/issues/5612
2022-08-22 15:01:35 +02:00
Eelco Dolstra
91b7d5373a
Style tweaks 2022-05-25 12:32:22 +02:00
Ben Burdette
2c9fafdc9e trying debugThrow 2022-05-06 08:47:21 -06:00
Ben Burdette
6e19947993 Merge branch 'master' into debug-merge-master 2022-04-28 12:32:57 -06:00
pennae
8775be3393 store Symbols in a table as well, like positions
this slightly increases the amount of memory used for any given symbol, but this
increase is more than made up for if the symbol is referenced more than once in
the EvalState that holds it. on average every symbol should be referenced at
least twice (once to introduce a binding, once to use it), so we expect no
increase in memory on average.

symbol tables are limited to 2³² entries like position tables, and similar
arguments apply to why overflow is not likely: 2³² symbols would require as many
string instances (at 24 bytes each) and map entries (at 24 bytes or more each,
assuming that the map holds on average at most one item per bucket as the docs
say). a full symbol table would require at least 192GB of memory just for
symbols, which is well out of reach. (an ofborg eval of nixpks today creates
less than a million symbols!)
2022-04-21 21:56:31 +02:00
pennae
6526d1676b replace most Pos objects/ptrs with indexes into a position table
Pos objects are somewhat wasteful as they duplicate the origin file name and
input type for each object. on files that produce more than one Pos when parsed
this a sizeable waste of memory (one pointer per Pos). the same goes for
ptr<Pos> on 64 bit machines: parsing enough source to require 8 bytes to locate
a position would need at least 8GB of input and 64GB of expression memory. it's
not likely that we'll hit that any time soon, so we can use a uint32_t index to
locate positions instead.
2022-04-21 21:46:06 +02:00
Ben Burdette
b8b8ec7101 move throw to preverve Error type; turn off debugger for tryEval 2022-04-08 12:34:27 -06:00
Daniel Pauls
fa83b865a2 libexpr: Throw the correct error in toJSON
BaseError::addTrace(...) returns a BaseError, but we want to
throw a TypeError instead.

Fixes #6336.
2022-03-30 15:50:13 +02:00
Ben Burdette
eaecaaa00b more debug_throw coverage of EvalErrors 2022-03-14 11:39:53 -06:00
Eelco Dolstra
b6c8e57056 Support range-based for loop over list values 2021-11-25 16:31:39 +01:00
Shay Bergmann
a50c027ece
toJSON: improve pos accuracy, add trace 2021-10-27 19:48:48 +00:00
Shay Bergmann
769de259f0
toJSON: pass pos in case of a list as well 2021-10-26 14:43:15 +00:00
Shay Bergmann
ba81e871b2
toJSON: report error position for fancier output
Given flake:

```nix
{ description = "nix json error provenance";
  inputs = {};
  outputs = { self }: {
    jsonFunction = _: "function";
    json = builtins.toJSON (_: "function");
  };
}

```
- Before:

```console
❯ nix eval --json .#jsonFunction
error: cannot convert a function to JSON
```

- After:

```console
❯ nix eval --json .#jsonFunction
error: cannot convert a function to JSON

       at /nix/store/b7imf1c2j4jnkg3ys7fsfbj02s5j0i4f-source/testflake/flake.nix:4:5:

            3|   outputs = { self }: {
            4|     jsonFunction = _: "function";
             |     ^
            5|     json = builtins.toJSON (_: "function");
```
2021-10-25 21:17:52 +00:00
Silvan Mosberger
12e65078ef
Rename Value::normalType() -> Value::type() 2020-12-17 14:45:45 +01:00
Silvan Mosberger
22ead43a0b
Use Value::normalType on all forced values instead of Value::type 2020-12-12 03:31:48 +01:00
Ben Burdette
e4fb9a3849 remove 'format' from Error constructor calls 2020-04-21 17:07:07 -06:00
Robin Gloster
e583df5280
builtins.toJSON: fix __toString usage 2019-10-27 10:15:51 +01:00
Eelco Dolstra
c0a7b84748 nix path-info: Add --json flag
Also, factor out JSON generation from value-to-json.{cc,hh}, and
support producing indented JSON.
2016-08-29 17:29:24 +02:00
Christian Theune
14ebde5289 First hit at providing support for floats in the language. 2016-01-05 00:40:40 +01:00
Eelco Dolstra
b83801f8b3 Optimize small lists
The value pointers of lists with 1 or 2 elements are now stored in the
list value itself. In particular, this makes the "concatMap (x: if
cond then [(f x)] else [])" idiom cheaper.
2015-07-23 22:05:09 +02:00
Eelco Dolstra
6bd2c7bb38 OCD: foreach -> C++11 ranged for 2015-07-17 20:13:56 +02:00
Shea Levy
608110804c Make all ExternalValueBase functions const 2014-12-02 10:27:10 -05:00
Shea Levy
320659b0cd Allow external code using libnixexpr to add types
Code that links to libnixexpr (e.g. plugins loaded with importNative, or
nix-exec) may want to provide custom value types and operations on
values of those types. For example, nix-exec is currently using sets
where a custom IO value type would be more appropriate. This commit
provides a generic hook for such types in the form of tExternal and the
ExternalBase virtual class, which contains all functions necessary for
libnixexpr's type-polymorphic functions (e.g. `showType`) to be
implemented.
2014-12-02 10:27:04 -05:00
Eelco Dolstra
d61853430a Support control characters in JSON output 2014-09-30 00:41:18 +02:00
Eelco Dolstra
5fea98111b Refactor JSON output 2013-11-19 00:33:06 +01:00
Eelco Dolstra
77c13cdf56 Add a toJSON primop 2013-11-19 00:04:11 +01:00