bug#32339: "nix import" fails

bug#32339: "nix import" fails

[Nils Gillmann]

Hooray, a bad subject line!

* nixpkgs is on commit d817ccbf832419abdd82bc617e058b8a196f6e98
* guix is on commit 6915d20f05363f61cef9c4ed7ebda3fe5a19325d
* GUIX_PACKAGE_PATH is unset

FWIW, this was while running the Nix daemon with my "service", but it
is not required for the imports.


abyayala$ guix import nix ~/re-src/nixpkgs curl
;;; SSAX warning: Skipping PI: xml

trace: stdenv.isArm is deprecated after 18.03
trace: lib.zip is deprecated, use lib.zipAttrsWith instead
trace: Warning: `showVal` is deprecated and will be removed in the next release, please use `traceSeqN`
trace: `mkStrict' is obsolete; use `mkOverride 0' instead.
trace: `lib.nixpkgsVersion` is deprecated, use `lib.version` instead!
error: stack overflow (possible infinite recursion)
Backtrace:
In guix/import/snix.scm:
    191:9 19 (loop #<input: #{read pipe}# 14> () #f _)
    191:9 18 (loop #<input: #{read pipe}# 14> () #f _)
    191:9 17 (loop #<input: #{read pipe}# 14> () #f _)
    191:9 16 (loop #<input: #{read pipe}# 14> () #f _)
    191:9 15 (loop #<input: #{read pipe}# 14> () #f _)
    191:9 14 (loop #<input: #{read pipe}# 14> () #f _)
    191:9 13 (loop #<input: #{read pipe}# 14> () #f _)
    191:9 12 (loop #<input: #{read pipe}# 14> () #f _)
    191:9 11 (loop #<input: #{read pipe}# 14> () #f _)
    191:9 10 (loop #<input: #{read pipe}# 14> () #f _)
    191:9  9 (loop #<input: #{read pipe}# 14> () #f _)
    191:9  8 (loop #<input: #{read pipe}# 14> () #f _)
    191:9  7 (loop #<input: #{read pipe}# 14> () #f _)
    191:9  6 (loop #<input: #{read pipe}# 14> () #f _)
    191:9  5 (loop #<input: #{read pipe}# 14> () #f _)
    191:9  4 (loop #<input: #{read pipe}# 14> () #f _)
    191:9  3 (loop #<input: #{read pipe}# 14> () #f _)
    191:9  2 (loop #<input: #{read pipe}# 14> () #f _)
    191:9  1 (loop #<input: #{read pipe}# 14> () #f _)
In sxml/upstream/SSAX.scm:
  1896:21  0 (_ #<input: #{read pipe}# 14> #f #<procedure 7f8b08622…> …)

sxml/upstream/SSAX.scm:1896:21: Throw to key `parser-error' with args `(#<input: #{read pipe}# 14> "EOF while 
reading a token " "reading char data")'.

bug#32339: Nix import

[Andreas Enge]

This bug is resolved by following the current documentation and
executing
   export NIX_REMOTE=daemon
.

However, even then the import fails:

$ guix import nix nixpkgs/ hello

;;; SSAX warning: Skipping PI: xml

trace: warning: `stdenv.isArm` is deprecated after 18.03. Please use `stdenv.isAarch32` instead
trace: lib.zip is deprecated, use lib.zipAttrsWith instead
trace: Warning: `showVal` is deprecated and will be removed in the next release, please use `traceSeqN`
trace: `mkStrict' is obsolete; use `mkOverride 0' instead.
trace: `lib.nixpkgsVersion` is deprecated, use `lib.version` instead!


And after about 15 minutes the import crashes with a stack overflow.

Andreas

bug#32339: Nix import

[Andreas Enge]

Sorry, I did not look at the error message well enough, the bug is indeed
still the same as reported.

Andreas

bug#32339: Nix import

[Andreas Enge]

So, I just discussed with a Nix expert, Profpatsch.

Apparently something changed in nixpkgs a while ago, so that the following
code does not work any more:
$ export NIX_REMOTE=daemon
$ nix-instantiate --eval --strict -A hello nixpkgs/
trace: `types.list` is deprecated; use `types.listOf` instead
trace: types.optionSet is deprecated; use types.submodule instead
trace: Warning: `showVal` is deprecated and will be removed in the next release, please use `traceSeqN`
trace: `lib.nixpkgsVersion` is deprecated, use `lib.version` instead!
trace: lib.zip is deprecated, use lib.zipAttrsWith instead
trace: `mkStrict' is obsolete; use `mkOverride 0' instead.
trace: warning: `stdenv.isArm` is deprecated after 18.03. Please use `stdenv.isAarch32` instead
trace: warning: `stdenv.isArm` is deprecated after 18.03. Please use `stdenv.isAarch32` instead
trace: warning: `stdenv.isArm` is deprecated after 18.03. Please use `stdenv.isAarch32` instead
trace: warning: `stdenv.isArm` is deprecated after 18.03. Please use `stdenv.isAarch32` instead
error: overrideDerivation not yet supported for functors
(use '--show-trace' to show detailed location information)

We should have checked the return value...

Omitting the "--strict" flag is not a solution, since then lazy evaluation
leads to most interesting fields of the result being empty (the return string
value is "<CODE>").

A potential solution is evaluating for different package fields separately,
but this would require more or less a complete rewrite of the importer.
I wonder if the solution would not be to drop it completely... Interestingly
enough, the programmatic nature of Nix makes it much more difficult to import
packages, since we cannot simply use the abstract syntax tree of the
textual representation of a package.

Here are a few possible commands to run:
$ nix-instantiate --eval --strict -E "with import $PATH_TO_NIXPKGS {}; singular.version"
"4.1.1p2"

$ nix-instantiate --eval --strict -E "with import $PATH_TO_NIXPKGS {}; map (drv: drv.name) singular.buildInputs"
[ "gmp-6.1.2" "ncurses-6.1-20190112" "readline-6.3p08" "ntl-11.3.2" "flint-2.5.2" "cddlib-0.94j" ]

$ nix-instantiate --eval --strict -E "with import $PATH_TO_NIXPKGS {}; map (drv: drv.name) singular.nativeBuildInputs"
[ "bison-3.3.2" "perl-5.28.2" "pkg-config-0.29.2" "hook" ]
(notice that there is now a difference between build and native build
inputs, and even more types)

$ nix-instantiate --eval --strict -E "with import $PATH_TO_NIXPKGS {}; singular.src"
[error message]

$ nix-instantiate --eval --strict -E "with import $PATH_TO_NIXPKGS {}; (singular.override { fetchurl = lib.id; }).src"
{ sha256 = "07x9kri8vl4galik7lr6pscq3c51n8570pyw64i7gbj0m706f7wf"; url = "http://www.mathematik.uni-kl.de/ftp/pub/Math/Singular/SOURCES/4-1-1/singular-4.1.1p2.tar.gz"; }

$ nix-instantiate --eval --strict -E "with import $PATH_TO_NIXPKGS {}; (linbox.override { fetchurl = lib.id; }).src"
[error message]

$ nix-instantiate --eval --strict -E "with import $PATH_TO_NIXPKGS {}; (linbox.override { fetchFromGitHub = lib.id; }).src"
{ owner = "linbox-team"; repo = "linbox"; rev = "v1.6.3"; sha256 = "10j6dspbsq7d2l4q3y0c1l1xwmaqqba2fxg59q5bhgk9h5d7q571"; }

So for the latter two cases, one would need to try both and catch errors.

Andreas

bug#32339: Nix import

[Ludovic Courtès]

Hello,

Andreas Enge <andreas@enge.fr> skribis:

> Omitting the "--strict" flag is not a solution, since then lazy evaluation
> leads to most interesting fields of the result being empty (the return string
> value is "<CODE>").

Do we know exactly why Nix stack-overflows?  Perhaps we’re evaluating
fields we shouldn’t evaluate?

It used to work :-), so something must have changed in the Nix
evaluation rules or in how Nixpkgs attribute sets are written.  We
should ask the Nix folks for guidance.

Ludo’.

bug#32339: "nix import" fails

[Ludovic Courtès]

‘guix import nix’ has now been removed:

  https://issues.guix.gnu.org/47871

Closing!

Ludo’.