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670 commits

Author SHA1 Message Date
Andreas Rammhold 059ae7f6c4
Add unit tests for libexpr (#5377)
* libexpr: fix builtins.split example

The example was previously indicating that multiple whitespaces would be
collapsed into a single captured whitespace. That isn't true and was
likely a mistake when being documented initially.

* Fix segfault on unitilized list when printing value

Since lists are just chunks of memory the individual elements in the
list might be unitilized when a programming error happens within Nix.

In this case the values are null-initialized (at least with Boehm GC)
and we can avoid a nullptr deref when printing them.

I ran into this issue while ensuring that new expression tests would
show the actual value on an assertion failure.

This is unlikely to cause any runtime performance regressions as
printing values is not really in the hot path (unless the repl is the
primary use case).

* Add operator<< for ValueTypes

* Add libexpr tests

This introduces tests for libexpr that evalulate various trivial Nix
language expressions and primop invocations that should be good smoke
tests wheter or not the implementation is behaving as expected.
2022-05-06 18:05:27 +02:00
Alain Zscheile 1385b20078
Get rid of most .at calls (#6393)
Use one of `get` or `getOr` instead which will either return a null-pointer (with a nicer error message) or a default value when the key is missing.
2022-05-04 07:44:32 +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
Théophane Hufschmitt c4ffc8e2f8
Merge pull request #6218 from pennae/pos-symbol-tables
reduce the size of Attr from 3 pointers to 2 on 64 bit machines
2022-04-22 10:28:06 +02:00
Tom Bereknyei f25112d383 fix: builtins.toFile adds path to allowedPaths
The produced path is then allowed be imported or utilized elsewhere:
```
assert (43 == import (builtins.toFile "source" "43")); "good"
```

This will still fail on write-only stores.
2022-04-21 16:41:37 -04:00
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 00a3280232 don't use Symbol in Pos to represent a path
PosTable deduplicates origin information, so using symbols for paths is no
longer necessary. moving away from path Symbols also reduces the usage of
symbols for things that are not keys in attribute sets, which will become
important in the future when we turn symbols into indices as well.
2022-04-21 21:46:10 +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
pennae 90b5c0a1a6 turn primop names into strings
we don't *need* symbols here. the only advantage they have over strings is
making call-counting slightly faster, but that's a diagnostic feature and thus
needn't be optimized.

this also fixes a move bug that previously didn't show up: PrimOp structs were
accessed after being moved from, which technically invalidates them. previously
the names remained valid because Symbol copies on move, but strings are
invalidated. we now copy the entire primop struct instead of moving since primop
registration happen once and are not performance-sensitive.
2022-04-21 21:25:17 +02:00
Eelco Dolstra fdfe737867 Fix handling of outputHash when outputHashAlgo is not specified
https://hydra.nixos.org/build/171351131
2022-04-01 12:40:49 +02:00
Eelco Dolstra 7537097284 Provide default values for outputHashAlgo and outputHashMode 2022-03-31 16:56:44 +02:00
Eelco Dolstra 5cd72598fe Add support for impure derivations
Impure derivations are derivations that can produce a different result
every time they're built. Example:

  stdenv.mkDerivation {
    name = "impure";
    __impure = true; # marks this derivation as impure
    outputHashAlgo = "sha256";
    outputHashMode = "recursive";
    buildCommand = "date > $out";
  };

Some important characteristics:

* This requires the 'impure-derivations' experimental feature.

* Impure derivations are not "cached". Thus, running "nix-build" on
  the example above multiple times will cause a rebuild every time.

* They are implemented similar to CA derivations, i.e. the output is
  moved to a content-addressed path in the store. The difference is
  that we don't register a realisation in the Nix database.

* Pure derivations are not allowed to depend on impure derivations. In
  the future fixed-output derivations will be allowed to depend on
  impure derivations, thus forming an "impurity barrier" in the
  dependency graph.

* When sandboxing is enabled, impure derivations can access the
  network in the same way as fixed-output derivations. In relaxed
  sandboxing mode, they can access the local filesystem.
2022-03-31 13:43:20 +02:00
Théophane Hufschmitt 390269ed87 Simplify the handling of the hash modulo
Rather than having four different but very similar types of hashes, make
only one, with a tag indicating whether it corresponds to a regular of
deferred derivation.

This implies a slight logical change: The original Nix+multiple-outputs
model assumed only one hash-modulo per derivation. Adding
multiple-outputs CA derivations changed this as these have one
hash-modulo per output. This change is now treating each derivation as
having one hash modulo per output.
This obviously means that we internally loose the guaranty that
all the outputs of input-addressed derivations have the same hash
modulo. But it turns out that it doesn’t matter because there’s nothing
in the code taking advantage of that fact (and it probably shouldn’t
anyways).

The upside is that it is now much easier to work with these hashes, and
we can get rid of a lot of useless `std::visit{ overloaded`.

Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems>
2022-03-29 18:17:35 +02:00
Eelco Dolstra 86b05ccd54 Only provide builtin.{getFlake,fetchClosure} is the corresponding experimental feature is enabled
This allows writing fallback code like

  if builtins ? fetchClosure then
    builtins.fetchClose { ... }
  else
    builtins.storePath ...
2022-03-25 14:04:18 +01:00
Eelco Dolstra d67fe90375
Merge pull request #6305 from flox/genericClosure_doc
docs: genericClosure
2022-03-24 14:02:58 +01:00
Tom Bereknyei 0736f3651d docs: genericClosure 2022-03-24 08:03:59 -04:00
Eelco Dolstra e4ff430866
Merge pull request #6237 from obsidiansystems/store-path-string-context
Decode string context straight to using StorePaths
2022-03-22 10:29:46 +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
John Ericson a544ed7684 Generalize DerivationType in preparation for impure derivations 2022-03-18 14:59:56 +00:00
John Ericson 049fae155a Avoid some pointless copying of drvs 2022-03-18 14:59:56 +00:00
John Ericson 8496be7def Use Deferred when building an input-addressed drv
Easier than using dummy path with input addressed.
2022-03-18 14:59:56 +00:00
John Ericson 197feed51d Clean up DerivationOutput, and headers
1. `DerivationOutput` now as the `std::variant` as a base class. And the
   variants are given hierarchical names under `DerivationOutput`.

   In 8e0d0689be @matthewbauer and I
   didn't know a better idiom, and so we made it a field. But this sort
   of "newtype" is anoying for literals downstream.

   Since then we leaned the base class, inherit the constructors trick,
   e.g. used in `DerivedPath`. Switching to use that makes this more
   ergonomic, and consistent.

2. `store-api.hh` and `derivations.hh` are now independent.

   In bcde5456cc I swapped the dependency,
   but I now know it is better to just keep on using incomplete types as
   much as possible for faster compilation and good separation of
   concerns.
2022-03-17 22:35:53 +00:00
John Ericson 0948b8e94d Reduce variants for derivation hash modulo
This changes was taken from dynamic derivation (#4628). It` somewhat
undoes the refactors I first did for floating CA derivations, as the
benefit of hindsight + requirements of dynamic derivations made me
reconsider some things.

They aren't to consequential, but I figured they might be good to land
first, before the more profound changes @thufschmitt has in the works.
2022-03-11 21:20:37 +00:00
Robert Hensing ee019d0afc Add EvalState::allowAndSetStorePathString helper
This switches addPath from `printStorePath` to `toRealPath`.
2022-02-28 21:37:49 +01:00
Eelco Dolstra df552ff53e Remove std::string alias (for real this time)
Also use std::string_view in a few more places.
2022-02-25 16:13:02 +01:00
Eelco Dolstra 1ac2664472 Remove std::vector alias 2022-02-21 16:32:34 +01:00
Eelco Dolstra fe9afb65bb Remove std::set alias 2022-02-21 16:28:23 +01:00
Eelco Dolstra afcdc7606c Remove std::list alias 2022-02-21 16:25:12 +01:00
Eelco Dolstra 4c755c3b3f Merge branch 'issue-3505' of https://github.com/kamadorueda/nix 2022-02-04 00:33:13 +01:00
Eelco Dolstra cd35bbbeef Merge branch 'more-stringviews' of https://github.com/pennae/nix 2022-02-02 12:38:37 +01:00
Thomas Koch 85b1427662 fix spelling mistakes reported by Debian's lintian tool 2022-01-30 10:51:39 +02:00
Eelco Dolstra 4bf6af7b55 Remove a repeated std::move in a for loop 2022-01-28 15:10:43 +01:00
pennae d439dceb3b optionally return string_view from coerceToString
we'll retain the old coerceToString interface that returns a string, but callers
that don't need the returned value to outlive the Value it came from can save
copies by using the new interface instead. for values that weren't stringy we'll
pass a new buffer argument that'll be used for storage and shouldn't be
inspected.
2022-01-27 22:15:30 +01:00
pennae 41d70a2fc8 return string_views from forceString*
once a string has been forced we already have dynamic storage allocated for it,
so we can easily reuse that storage instead of copying.
2022-01-27 17:15:43 +01:00
regnat fcdc60ed22 Don’t require NIX_PATH entries to be valid paths
It’s totally valid to have entries in `NIX_PATH` that aren’t valid paths
(they can even be arbitrary urls or `channel:<channel-name>`).

Fix #5998 and #5980
2022-01-27 16:26:39 +01:00
Eelco Dolstra 8cbbaf23e8 Allow builtins.{readFile,path} on invalid paths
Stop-gap measure to fix #5975.
2022-01-24 23:02:28 +01:00
Kevin Amado c3896e19d0
forceAttrs: make pos mandatory 2022-01-21 16:32:43 -05:00
Eelco Dolstra 128098040b
Fix exception handling around realisePath()
This no longer worked correctly because 'path' is uninitialised when
an exception occurs, leading to errors like

       … while importing ''

       at /nix/store/rrzz5b1pshvzh1437ac9nkl06br81lkv-source/flake.nix:352:13:

So move the adding of the error context into realisePath().
2022-01-21 13:53:18 +01:00
Eelco Dolstra 4af88a4c91
Merge pull request #5906 from pennae/primops-optimization
optimize primops and utils by caching more and copying less
2022-01-18 19:43:28 +01:00
Eelco Dolstra fc2443a67c
Merge pull request #5812 from pennae/small-perf-improvements
improve parser performance a bit
2022-01-17 19:49:52 +01:00
pennae ad60dfde2a also cache split regexes, not just match regexes
gives about 1% improvement on system eval, a bit less on nix search.

 # before

  nix search --no-eval-cache --offline ../nixpkgs hello
    Time (mean ± σ):      7.419 s ±  0.045 s    [User: 6.362 s, System: 0.794 s]
    Range (min … max):    7.335 s …  7.517 s    20 runs

  nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
    Time (mean ± σ):      2.921 s ±  0.023 s    [User: 2.626 s, System: 0.210 s]
    Range (min … max):    2.883 s …  2.957 s    20 runs

 # after

  nix search --no-eval-cache --offline ../nixpkgs hello
    Time (mean ± σ):      7.370 s ±  0.059 s    [User: 6.333 s, System: 0.791 s]
    Range (min … max):    7.286 s …  7.541 s    20 runs

  nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
    Time (mean ± σ):      2.891 s ±  0.033 s    [User: 2.606 s, System: 0.210 s]
    Range (min … max):    2.823 s …  2.958 s    20 runs
2022-01-14 14:04:17 +01:00
pennae c9fc975259 optimize removeAttrs builtin
use a sorted array of symbols to be removed instead of a set. this saves a lot
of memory allocations and slightly speeds up removal.
2022-01-14 14:01:52 +01:00
pennae 34e3bd10e3 avoid copies of parser input data
when given a string yacc will copy the entire input to a newly allocated
location so that it can add a second terminating NUL byte. since the
parser is a very internal thing to EvalState we can ensure that having
two terminating NUL bytes is always possible without copying, and have
the parser itself merely check that the expected NULs are present.

 # before

Benchmark 1: nix search --offline nixpkgs hello
  Time (mean ± σ):     572.4 ms ±   2.3 ms    [User: 563.4 ms, System: 8.6 ms]
  Range (min … max):   566.9 ms … 579.1 ms    50 runs

Benchmark 2: nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix
  Time (mean ± σ):     381.7 ms ±   1.0 ms    [User: 348.3 ms, System: 33.1 ms]
  Range (min … max):   380.2 ms … 387.7 ms    50 runs

Benchmark 3: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
  Time (mean ± σ):      2.936 s ±  0.005 s    [User: 2.715 s, System: 0.221 s]
  Range (min … max):    2.923 s …  2.946 s    50 runs

 # after

Benchmark 1: nix search --offline nixpkgs hello
  Time (mean ± σ):     571.7 ms ±   2.4 ms    [User: 563.3 ms, System: 8.0 ms]
  Range (min … max):   566.7 ms … 579.7 ms    50 runs

Benchmark 2: nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix
  Time (mean ± σ):     376.6 ms ±   1.0 ms    [User: 345.8 ms, System: 30.5 ms]
  Range (min … max):   374.5 ms … 379.1 ms    50 runs

Benchmark 3: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
  Time (mean ± σ):      2.922 s ±  0.006 s    [User: 2.707 s, System: 0.215 s]
  Range (min … max):    2.906 s …  2.934 s    50 runs
2022-01-13 18:06:15 +01:00
pennae 6401e443a4 move strings in derivationStrict
the temporary will be discarded anyway, so we can move out of it and save many
small allocations and copies.
2022-01-13 14:00:20 +01:00
pennae ef45787aae avoid string copies in attrNames sort comparison
symbols can also be cast to string_view, which compares the same but doesn't
require a copy of both symbol names on every comparison.
2022-01-13 14:00:19 +01:00
pennae 1bebb1095a cache more often-used symbols for primops
there's a few symbols in primops we can create once and pick them out of
EvalState afterwards instead of creating them every time we need them. this
gives almost 1% speedup to an uncached nix search.
2022-01-13 13:58:33 +01:00
Nikolay Amiantov c66865dff1 builtins.readFile: Propagate path context
Co-authored-by: Shea Levy <shea@shealevy.com>
2022-01-09 13:07:00 +03:00
Eelco Dolstra 2b4c944823 Remove EvalState::mkAttrs() 2022-01-04 20:29:17 +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