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79 commits

Author SHA1 Message Date
Robert Hensing
7b39a388b3
Merge pull request #8566 from inclyc/nixd/value-print-depth
libexpr: extend `Value::print` to allow limited depth
2023-07-01 20:08:52 +02:00
John Ericson
22b278e011 Automatically document builtin constants
This is done in roughly the same way builtin functions are documented.

Also auto-link experimental features for primops, subsuming PR #8371.

Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
2023-06-27 09:37:54 -04:00
Yingchi Long
1400fde144 libexpr: extend Value::print to allow limited depth 2023-06-22 18:28:30 +08:00
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
Robert Hensing
cb2615cf47 Merge remote-tracking branch 'upstream/master' into source-path 2023-04-17 11:41:50 +02:00
John Ericson
0746951be1
Finish converting existing comments for internal API docs (#8146)
* Finish converting existing comments for internal API docs

99% of this was just reformatting existing comments. Only two exceptions:

- Expanded upon `BuildResult::status` compat note

- Split up file-level `symbol-table.hh` doc comments to get
  per-definition docs

Also fixed a few whitespace goofs, turning leading tabs to spaces and
removing trailing spaces.

Picking up from #8133

* Fix two things from comments

* Use triple-backtick not indent for `dumpPath`

* Convert GNU-style `\`..'` quotes to markdown style in API docs

This will render correctly.
2023-04-07 13:55:28 +00:00
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
John Ericson
f4ab297b31 Ensure all headers have #pragma once and are in API docs
`///@file` makes them show up in the internal API dos. A tiny few were
missing `#pragma once`.
2023-03-31 23:19:44 -04:00
Robert Hensing
9b33ef3879 Revert "Merge pull request #6204 from layus/coerce-string"
This reverts commit a75b7ba30f, reversing
changes made to 9af16c5f74.
2023-01-18 01:34:07 +01:00
John Ericson
5576d5e987 Parse string context elements properly
Prior to this change, we had a bunch of ad-hoc string manipulation code
scattered around. This made it hard to figure out what data model for
string contexts is.

Now, we still store string contexts most of the time as encoded strings
--- I was wary of the performance implications of changing that --- but
whenever we parse them we do so only through the
`NixStringContextElem::parse` method, which handles all cases. This
creates a data type that is very similar to `DerivedPath` but:

 - Represents the funky `=<drvpath>` case as properly distinct from the
   others.

 - Only encodes a single output, no wildcards and no set, for the
   "built" case.

(I would like to deprecate `=<path>`, after which we are in spitting
distance of `DerivedPath` and could maybe get away with fewer types, but
that is another topic for another day.)
2023-01-10 13:10:49 -05:00
Eelco Dolstra
6b69652385 Merge remote-tracking branch 'origin/master' into coerce-string 2023-01-02 20:53:39 +01:00
Yorick van Pelt
09f00dd4d0
Replace src/libutil/json.cc with nlohmann json generation 2022-11-16 16:50:50 +01:00
Guillaume Maudoux
eb460a9529 WIP: broken merge but need a git checkpoint 2022-09-07 00:34:03 +02:00
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
9acc770ce4
Remove pre-C++11 hackiness 2022-05-26 12:40:01 +02:00
Guillaume Maudoux
e93b59fbc5 Merge remote-tracking branch 'origin/master' into coerce-string 2022-04-29 00:12:25 +02:00
Guillaume Maudoux
402ee8ab64 No point in passing string_views by reference 2022-04-28 13:02:39 +02:00
pennae
a385e51a08 rename SymbolIdx -> Symbol, Symbol -> SymbolStr
after #6218 `Symbol` no longer confers a uniqueness invariant on the
string it wraps, it is now possible to create multiple symbols that
compare equal but whose string contents have different addresses. this
guarantee is now only provided by `SymbolIdx`, leaving `Symbol` only as
a string wrapper that knows about the intricacies of how symbols need to
be formatted for output.

this change renames `SymbolIdx` to `Symbol` to restore the previous
semantics of `Symbol` to that name. we also keep the wrapper type and
rename it to `SymbolStr` instead of returning plain strings from lookups
into the symbol table because symbols are formatted for output in many
places. theoretically we do not need `SymbolStr`, only a function that
formats a string for output as a symbol, but having to wrap every symbol
that appears in a message into eg `formatSymbol()` is error-prone and
inconvient.
2022-04-25 15:37:01 +02:00
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
Eelco Dolstra
a0259a21a4 Don't hide repeated values while generating manifest.nix
Fixes #6243.
2022-03-22 13:18:56 +01:00
John Ericson
4d6a3806d2 Decode string context straight to using StorePaths
I gather decoding happens on demand, so I hope don't think this should
have any perf implications one way or the other.
2022-03-18 15:36:11 +00:00
Guillaume Maudoux
e6d07e0d89 Refactor to use more traces and less string manipulations 2022-03-18 00:58:09 +01:00
John Ericson
91adfb8894 Create some type aliases for string Contexts 2022-03-11 22:30:10 +00:00
Guillaume Maudoux
3a5855353e Add detailed error mesage for coerceTo{String,Path} 2022-03-04 21:47:58 +01:00
Eelco Dolstra
e9c04c3351 Be more aggressive in hiding repeated values
We now memoize on Bindings / list element vectors rather than Values,
so that e.g. two Values that point to the same Bindings will be
printed only once.
2022-03-03 13:33:34 +01:00
Eelco Dolstra
ecff9d969a printValue(): Don't show repeated values
Fixes #6157.
2022-03-03 13:18:23 +01:00
Eelco Dolstra
36c7b12f33 Remove std::string alias 2022-02-21 16:37:25 +01:00
Eelco Dolstra
bd383d1b6f Make most calls to determinePos() lazy 2022-02-04 00:33:21 +01:00
pennae
5838354d34 optimize ExprConcatStrings::eval
constructing an ostringstream for non-string concats (like integer addition) is
a small constant cost that we can avoid. for string concats we can keep all the
string temporaries we get from coerceToString and concatenate them in one go,
which saves a lot of intermediate temporaries and copies in ostringstream. we
can also avoid copying the concatenated string again by directly allocating it
in GC memory and moving ownership of the concatenated string into the target
value.

saves about 2% on system eval.

before:

  Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
    Time (mean ± σ):      2.837 s ±  0.031 s    [User: 2.562 s, System: 0.191 s]
    Range (min … max):    2.796 s …  2.892 s    20 runs

after:

  Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
    Time (mean ± σ):      2.790 s ±  0.035 s    [User: 2.532 s, System: 0.187 s]
    Range (min … max):    2.722 s …  2.836 s    20 runs
2022-01-12 10:07:21 +01:00
Eelco Dolstra
ca5baf2392 Turn mkString(Symbol) into a method 2022-01-04 19:09:40 +01:00
Eelco Dolstra
ed93aec3c3 Remove non-method mkPath() 2022-01-04 18:45:16 +01:00
Eelco Dolstra
263a8d293c Remove non-method mk<X> functions 2022-01-04 18:40:39 +01:00
Eelco Dolstra
cc08364315 Remove non-method mkString() 2022-01-04 18:24:42 +01:00
Eelco Dolstra
6d9a6d2cc3 Ensure that attrsets are sorted
Previously you had to remember to call value->attrs->sort() after
populating value->attrs. Now there is a BindingsBuilder helper that
wraps Bindings and ensures that sort() is called before you can use
it.
2022-01-04 18:00:33 +01:00
Silvan Mosberger
90700736c7 Introduce builtins.groupBy primop
This function is very useful in nixpkgs, but its implementation in Nix
itself is rather slow due to it requiring a lot of attribute set and
list appends.
2021-12-02 21:54:51 +01:00
Eelco Dolstra
b6c8e57056 Support range-based for loop over list values 2021-11-25 16:31:39 +01:00
Kevin Amado
d0e9e18489
toXML: display errors position
- This change applies to builtins.toXML and inner workings
- Proof of concept:
  ```nix
  let e = builtins.toXML e; in e
  ```
- Before:
  ```
  $ nix-instantiate --eval poc.nix
  error: infinite recursion encountered
  ```
- After:
  ```
  $ nix-instantiate --eval poc.nix
  error: infinite recursion encountered

       at /data/github/kamadorueda/nix/poc.nix:1:9:

            1| let e = builtins.toXML e; in e
             |
  ```
2021-11-13 20:33:34 -05:00
Maximilian Bosch
7c76964daa
libexpr: misc improvements for proper error position
When working on some more complex Nix code, there are sometimes rather
unhelpful or misleading error messages, especially if coerce-errors are
thrown.

This patch is a first steps towards improving that. I'm happy to file
more changes after that, but I'd like to gather some feedback first.

To summarize, this patch does the following things:

* Attrsets (a.k.a. `Bindings` in `libexpr`) now have a `Pos`. This is
  helpful e.g. to identify which attribute-set in `listToAttrs` is
  invalid.

* The `Value`-struct has a new method named `determinePos` which tries
  to guess the position of a value and falls back to a default if that's
  not possible.

  This can be used to provide better messages if a coercion fails.

* The new `determinePos`-API is used by `builtins.concatMap` now. With
  that change, Nix shows the exact position in the error where a wrong
  value was returned by the lambda.

  To make sure it's still obvious that `concatMap` is the problem,
  another stack-frame was added.

* The changes described above can be added to every other `primop`, but
  first I'd like to get some feedback about the overall approach.
2021-04-13 23:12:38 +02:00
Silvan Mosberger
b70d22baca
Replace Value type setters with mk* functions
Move clearValue inside Value

mkInt instead of setInt

mkBool instead of setBool

mkString instead of setString

mkPath instead of setPath

mkNull instead of setNull

mkAttrs instead of setAttrs

mkList instead of setList*

mkThunk instead of setThunk

mkApp instead of setApp

mkLambda instead of setLambda

mkBlackhole instead of setBlackhole

mkPrimOp instead of setPrimOp

mkPrimOpApp instead of setPrimOpApp

mkExternal instead of setExternal

mkFloat instead of setFloat

Add note that the static mk* function should be removed eventually
2020-12-18 21:48:22 +01:00
Silvan Mosberger
12e65078ef
Rename Value::normalType() -> Value::type() 2020-12-17 14:45:45 +01:00
Silvan Mosberger
d67e02919c
Rename ValueType -> InternalType, NormalType -> ValueType
And Value::type to Value::internalType, such that type() can be used in
the next commit to get the new ValueType
2020-12-17 14:45:22 +01:00
Silvan Mosberger
730b152b19
Make Value::type private
This is an implementation detail and shouldn't be used. Use normalType()
and the various is<Type> functions instead
2020-12-12 03:31:52 +01:00
Silvan Mosberger
bf98903967
Add ValueType checking functions for types that have the same NormalType 2020-12-12 03:31:50 +01:00
Silvan Mosberger
9f056f7afd
Introduce Value type setters and make use of them 2020-12-12 03:31:48 +01:00
Silvan Mosberger
fa307875e9
Introduce NormalType for the normal type of a Value
This will be useful to abstract over the ValueType implementation
details

Make use of it already to replace the showType(ValueType) function
2020-12-12 03:31:46 +01:00
Eelco Dolstra
50f13b06fb EvalCache: Store string contexts 2020-06-29 19:08:37 +02:00
Eelco Dolstra
f89349f07e Merge remote-tracking branch 'origin/master' into flakes 2020-04-16 18:33:10 +02:00
Eelco Dolstra
10e17eaa58 ValueMap, VectorVector: Use traceable_allocator
We want to *trace* the 'Value *' arrays, not garbage-collect them!
Otherwise the vectors/maps can end up pointing to nowhere.

Fixes #3377. Closes #3384.
2020-04-16 17:30:13 +02:00