Commit graph

36 commits

Author SHA1 Message Date
pennae a2bf8a66a2 diagnose "unexpected EOF" at EOF
this needs a string comparison because there seems to be no other way to
get that information out of bison. usually the location info is going to
be correct (pointing at a bad token), but since EOF isn't a token as
such it'll be wrong in that this case.

this hasn't shown up much so far because a single line ending *is* a
token, so any file formatted in the usual manner (ie, ending in a line
ending) would have its EOF position reported correctly.
2024-02-26 15:49:57 +01:00
pennae 72396e0038 match line endings used by parser and error reports
the parser treats a plain \r as a newline, error reports do not. this
can lead to interesting divergences if anything makes use of this
feature, with error reports pointing to wrong locations in the input (or
even outside the input altogether).
2024-02-26 15:49:57 +01:00
pennae f7e3a0b19f report inherit attr errors at the duplicate name
previously we reported the error at the beginning of the binding
block (for plain inherits) or the beginning of the attr list (for
inherit-from), effectively hiding where exactly the error happened.

this also carries over to runtime positions of attributes in sets as
reported by unsafeGetAttrPos. we're not worried about this changing
observable eval behavior because it *is* marked unsafe, and the new
behavior is much more useful.
2024-02-26 15:49:56 +01:00
pennae b7cac2b2dc normalize formal order on ExprLambda::show
we already normalize attr order to lexicographic, doing the same for
formals makes sense. doubly so because the order of formals would
otherwise depend on the context of the expression, which is not quite as
useful as one might expect.
2024-02-26 15:44:54 +01:00
pennae f416527164 keep copies of parser inputs that are in-memory only
the parser modifies its inputs, which means that sharing them between
the error context reporting system and the parser itself can confuse the
reporting system. usually this led to early truncation of error context
reports which, while not dangerous, can be quite confusing.
2024-02-26 15:44:54 +01:00
pennae a704123ea1 evaluate inherit (from) exprs only once per directive
desugaring inherit-from to syntactic duplication of the source expr also
duplicates side effects of the source expr (such as trace calls) and
expensive computations (such as derivationStrict).
2024-02-26 15:37:40 +01:00
pennae ecf8b12d60 group inherit by source during Expr::show
for plain inherits this is really just a stylistic choice, but for
inherit-from it actually fixes an exponential size increase problem
during expr printing (as may happen during assertion failure reporting,
on during duplicate attr detection in the parser)
2024-02-12 13:58:29 +01:00
pennae 6c08fba533 use the same bindings print for ExprAttrs and ExprLet
this also has the effect of sorting let bindings lexicographically
rather than by symbol creation order as was previously done, giving a
better canonicalization in the process.
2024-02-12 13:35:00 +01:00
pennae 73065a400d add test for inherit expr printing 2024-02-12 13:32:33 +01:00
pennae 8669c02468 add test for inherit-from semantics 2024-02-12 13:32:33 +01:00
Rebecca Turner c6a89c1a16
libexpr: Support structured error classes
While preparing PRs like #9753, I've had to change error messages in
dozens of code paths. It would be nice if instead of

    EvalError("expected 'boolean' but found '%1%'", showType(v))

we could write

    TypeError(v, "boolean")

or similar. Then, changing the error message could be a mechanical
refactor with the compiler pointing out places the constructor needs to
be changed, rather than the error-prone process of grepping through the
codebase. Structured errors would also help prevent the "same" error
from having multiple slightly different messages, and could be a first
step towards error codes / an error index.

This PR reworks the exception infrastructure in `libexpr` to
support exception types with different constructor signatures than
`BaseError`. Actually refactoring the exceptions to use structured data
will come in a future PR (this one is big enough already, as it has to
touch every exception in `libexpr`).

The core design is in `eval-error.hh`. Generally, errors like this:

    state.error("'%s' is not a string", getAttrPathStr())
      .debugThrow<TypeError>()

are transformed like this:

    state.error<TypeError>("'%s' is not a string", getAttrPathStr())
      .debugThrow()

The type annotation has moved from `ErrorBuilder::debugThrow` to
`EvalState::error`.
2024-02-01 16:39:38 -08:00
Rebecca Turner 772897a1cd
Color diff output in tests/functional/lang tests
Use `diff --color=always` to print colored output for language test
failures. I've also flipped the arguments so that expected lines missing
from the actual output will be marked with a red `-` and additional
lines found in the actual output will be marked with a green `+`.
Previously it was the other way around, which was very confusing.
2024-01-26 10:08:56 -08:00
Rebecca Turner 83bb494a30
Print the value in error: cannot coerce messages
This extends the `error: cannot coerce a TYPE to a string` message
to print the value that could not be coerced. This helps with debugging
by making it easier to track down where the value is being produced
from, especially in errors with deep or unhelpful stack traces.
2024-01-23 15:15:41 -08:00
Rebecca Turner cb7fbd4d83
Print value on type error
Adds the failing value to `value is <TYPE> while a <TYPE> is expected`
error messages.
2024-01-22 08:56:02 -08:00
Robert Hensing cbc319e9be tests/functional/lang: Test substring with negative length 2024-01-16 12:19:31 +01:00
Robert Hensing b2deff1947
Merge pull request #9747 from awakesecurity/mz/fix-quadratic-splitString
Fix performance of builtins.substring for empty substrings
2024-01-16 12:18:59 +01:00
Mel Zuser 1996105e91 added test for empty substring special case 2024-01-12 09:40:21 -08:00
Rebecca Turner df84dd4d8d
Restore ambiguous value printer for nix-instantiate
The Nix team has requested that this output format remain unchanged.
I've added a warning to the man page explaining that `nix-instantiate
--eval` output will not parse correctly in many situations.
2024-01-11 16:34:36 -08:00
Rebecca Turner 0fa08b4516
Unify and refactor value printing
Previously, there were two mostly-identical value printers -- one in
`libexpr/eval.cc` (which didn't force values) and one in
`libcmd/repl.cc` (which did force values and also printed ANSI color
codes).

This PR unifies both of these printers into `print.cc` and provides a
`PrintOptions` struct for controlling the output, which allows for
toggling whether values are forced, whether repeated values are tracked,
and whether ANSI color codes are displayed.

Additionally, `PrintOptions` allows tuning the maximum number of
attributes, list items, and bytes in a string that will be displayed;
this makes it ideal for contexts where printing too much output (e.g.
all of Nixpkgs) is distracting. (As requested by @roberth in
https://github.com/NixOS/nix/pull/9554#issuecomment-1845095735)

Please read the tests for example output.

Future work:
- It would be nice to provide this function as a builtin, perhaps
  `builtins.toStringDebug` -- a printing function that never fails would
  be useful when debugging Nix code.
- It would be nice to support customizing `PrintOptions` members on the
  command line, e.g. `--option to-string-max-attrs 1000`.
2024-01-11 16:34:36 -08:00
Rebecca Turner 7434caca05
Fix segfault on infinite recursion in some cases
This fixes a segfault on infinite function call recursion (rather than
infinite thunk recursion) by tracking the function call depth in
`EvalState`.

Additionally, to avoid printing extremely long stack traces, stack
frames are now deduplicated, with a `(19997 duplicate traces omitted)`
message. This should only really be triggered in infinite recursion
scenarios.

Before:

    $ nix-instantiate --eval --expr '(x: x x) (x: x x)'
    Segmentation fault: 11

After:

    $ nix-instantiate --eval --expr '(x: x x) (x: x x)'
    error: stack overflow

           at «string»:1:14:
                1| (x: x x) (x: x x)
                 |              ^

    $ nix-instantiate --eval --expr '(x: x x) (x: x x)' --show-trace
    error:
           … from call site
             at «string»:1:1:
                1| (x: x x) (x: x x)
                 | ^

           … while calling anonymous lambda
             at «string»:1:2:
                1| (x: x x) (x: x x)
                 |  ^

           … from call site
             at «string»:1:5:
                1| (x: x x) (x: x x)
                 |     ^

           … while calling anonymous lambda
             at «string»:1:11:
                1| (x: x x) (x: x x)
                 |           ^

           … from call site
             at «string»:1:14:
                1| (x: x x) (x: x x)
                 |              ^

           (19997 duplicate traces omitted)

           error: stack overflow
           at «string»:1:14:
                1| (x: x x) (x: x x)
                 |              ^
2023-12-29 22:16:44 -08:00
Rebecca Turner 5cb98095ba
Remove some blank lines from stack traces
This keeps hint messages, source location information, and source code
snippets grouped together, while making stack traces shorter (so that
more stack frames can be viewed on the same terminal).

Before:

    error:
           … while evaluating the attribute 'body'

             at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:4:3:

                3|
                4|   body = x "x";
                 |   ^
                5| }

           … from call site

             at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:4:10:

                3|
                4|   body = x "x";
                 |          ^
                5| }

           … while calling 'x'

             at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:2:7:

                1| let {
                2|   x = arg: assert arg == "y"; 123;
                 |       ^
                3|

           error: assertion '(arg == "y")' failed

           at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:2:12:

                1| let {
                2|   x = arg: assert arg == "y"; 123;
                 |            ^
                3|

After:

    error:
           … while evaluating the attribute 'body'
             at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:4:3:
                3|
                4|   body = x "x";
                 |   ^
                5| }

           … from call site
             at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:4:10:
                3|
                4|   body = x "x";
                 |          ^
                5| }

           … while calling 'x'
             at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:2:7:
                1| let {
                2|   x = arg: assert arg == "y"; 123;
                 |       ^
                3|

           error: assertion '(arg == "y")' failed
           at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:2:12:
                1| let {
                2|   x = arg: assert arg == "y"; 123;
                 |            ^
                3|
2023-12-15 23:57:26 -08:00
Robert Hensing c8458bd731
Merge pull request #9555 from 9999years/positions-in-errors
Pass positions when evaluating
2023-12-09 03:55:58 +01:00
Robert Hensing 6e8d598314 tests/lang/eval-fail-bad-string-interpolation-4: init 2023-12-09 02:52:49 +01:00
Robert Hensing 9b7b7a7561 Revert "Print the value in error: cannot coerce messages (#9553)"
This reverts commit f0ac2a35d5.

The request from the sibling PR, which also applies here, was not addressed.
https://github.com/NixOS/nix/pull/9554#issuecomment-1845095735
2023-12-09 02:13:32 +01:00
Rebecca Turner f0ac2a35d5
Print the value in error: cannot coerce messages (#9553)
* Print the value in `error: cannot coerce` messages

This extends the `error: cannot coerce a TYPE to a string` message
to print the value that could not be coerced. This helps with debugging
by making it easier to track down where the value is being produced
from, especially in errors with deep or unhelpful stack traces.

Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
2023-12-08 16:36:57 +00:00
Rebecca Turner 0b80935c22
Pass positions when evaluating
This includes position information in more places, making debugging
easier.

Before:

```
$ nix-instantiate --show-trace --eval tests/functional/lang/eval-fail-using-set-as-attr-name.nix
error:
       … while evaluating an attribute name

         at «none»:0: (source not available)

       error: value is a set while a string was expected
```

After:

```
error:
       … while evaluating an attribute name

         at /pwd/lang/eval-fail-using-set-as-attr-name.nix:5:10:

            4| in
            5|   attr.${key}
             |          ^
            6|

       error: value is a set while a string was expected
```
2023-12-07 10:27:21 -08:00
Peter Kolloch fc6f29053a Renamed HashFormat::Base32 to HashFormat::Nix32
...and also adjusted parsing accordingly.

Also added CLI completion for HashFormats.

https://github.com/NixOS/nix/issues/8876
2023-12-06 23:43:42 +01:00
Eelco Dolstra 31ebc6028b Fix symlink handling
This restores the symlink handling behaviour prior to
94812cca98.

Fixes #9298.
2023-11-16 16:45:14 +01:00
Eelco Dolstra cdb27c1519 SourceAccessor: Change the main interface from lstat() to maybeLstat() 2023-11-01 15:26:07 +01:00
John Ericson 765436e300 Add builtins.addDrvOutputDependencies
End goal: make `(mkDerivation x).drvPath` behave like a non-DrvDeep
context.

Problem: users won't be able to recover the DrvDeep behavior when
nixpkgs makes this change.

Solution: add this primop.

The new primop is fairly simple, and is supposed to complement other
existing ones (`builtins.storePath`, `builtins.outputOf`) so there are
simple ways to construct strings with every type of string context
element.

(It allows nothing we couldn't already do with `builtins.getContext` and `builtins.appendContext`, which is also true of those other two primops.)

This was originally in #8595, but then it was proposed to land some doc
changes separately. So now the code changes proper is just moved to
this, and the doc will be done in that.

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Co-authored-by: Théophane Hufschmitt <7226587+thufschmitt@users.nore
github.com>
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io
2023-10-23 12:49:14 -04:00
Eelco Dolstra 955bbe53c5
Merge pull request #9177 from edolstra/input-accessors
Backport FSInputAccessor and MemoryInputAccessor from lazy-trees
2023-10-23 11:42:04 +02:00
Eelco Dolstra 7a086a32bc fetchToStore(): Handle flat ingestion method and add test 2023-10-20 13:32:15 +02:00
Eelco Dolstra 173abec0bc coerceToPath(): Handle __toString, add tests 2023-10-20 13:06:44 +02:00
Yueh-Shun Li 5088e6563a primops: add builtins.convertHash
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
2023-10-19 00:58:56 +08:00
John Ericson f7a36f9812 Fix language tests a bit
- Remove some stray saved error messages that didn't correspond to any
  test, because they were renamed in
  d11faa01b5.

- Need `--eval` in test failure test in order to get in "read-only" mode
  where we don't try to write to the store. (The other tests already do
  this.)

- Need `--strict` so top-level attribute sets are still forced, like
  they are without `--eval`.
2023-10-16 12:52:59 -04:00
John Ericson 68c81c7375 Put functional tests in tests/functional
I think it is bad for these reasons when `tests/` contains a mix of
functional and integration tests

 - Concepts is harder to understand, the documentation makes a good
   unit vs functional vs integration distinction, but when the
   integration tests are just two subdirs within `tests/` this is not
   clear.

 - Source filtering in the `flake.nix` is more complex. We need to
   filter out some of the dirs from `tests/`, rather than simply pick
   the dirs we want and take all of them. This is a good sign the
   structure of what we are trying to do is not matching the structure
   of the files.

With this change we have a clean:
```shell-session
$ git show 'HEAD:tests'
tree HEAD:tests

functional/
installer/
nixos/
```
2023-10-06 09:05:56 -04:00