elixir-ls: fix elixir stdlib code detection, elixir: fix deterministic builds and 1.17 max OTP

[adamcstephens]

• Fixes enabling deterministic builds for Elixir
• Cleans up and patches elixir-ls to properly find Elixir stdlib

After digging into this, I realized this elixir-ls package is wrong in multiple ways. It's built as a mix release, but packaged as a set of scripts which will Mix.install elixir-ls from git. I plan to clean this up in a future PR, but this should fix the immediate problems.

Closes #422529

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• Nixpkgs 25.11 Release Notes (or backporting 25.05 Nixpkgs Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
• NixOS 25.11 Release Notes (or backporting 25.05 NixOS Release notes)
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other contributing documentation in corresponding paths.

---

Add a 👍 reaction to pull requests you find important.

[happysalada]

Nothing to add

[Munksgaard]

I'm on vacation this week, so I likely won't have a chance to review. If it works I'm happy 😊

[adamcstephens]

It appears something changed in the most recent staging merge to master, and now some mixRelease packages are failing. e.g. next-ls, livebook and probably the others.

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 423588
Commit: ffd70542a12b1d01bd103adeec3946dd0e6c3a79

---

aarch64-linux

❌ 10 packages failed to build:

• firezone-server (firezone-server-domain)
• firezone-server-api
• firezone-server-web
• livebook
• next-ls
• plausible
• rabbitmq-server
• rabbitmq-server.doc
• rabbitmq-server.man
• sonic-pi

✅ 47 packages built:

• akkoma
• beam26Packages.elixir (beam26Packages.elixir_1_18)
• beam26Packages.elixir-ls
• beam26Packages.elixir_1_14
• beam26Packages.elixir_1_15
• beam26Packages.elixir_1_16
• beam26Packages.elixir_1_17
• beam26Packages.elixir_1_19
• beam26Packages.ex_doc
• beam26Packages.hex
• elixir (beam27Packages.elixir, elixir_1_18)
• elixir-ls (beam27Packages.elixir-ls)
• elixir_1_17 (beam27Packages.elixir_1_17)
• elixir_1_19 (beam27Packages.elixir_1_19)
• ex_doc (beam27Packages.ex_doc)
• beam27Packages.hex
• beam28Packages.elixir (beam28Packages.elixir_1_18)
• beam28Packages.elixir-ls
• beam28Packages.elixir_1_19
• beam28Packages.ex_doc
• beam28Packages.hex
• beamMinimal26Packages.elixir (beamMinimal26Packages.elixir_1_18)
• beamMinimal26Packages.elixir-ls
• beamMinimal26Packages.elixir_1_14
• beamMinimal26Packages.elixir_1_15
• beamMinimal26Packages.elixir_1_16
• beamMinimal26Packages.elixir_1_17
• beamMinimal26Packages.elixir_1_19
• beamMinimal26Packages.ex_doc
• beamMinimal26Packages.hex
• beamMinimal27Packages.elixir (beamMinimal27Packages.elixir_1_18)
• beamMinimal27Packages.elixir-ls
• beamMinimal27Packages.elixir_1_17
• beamMinimal27Packages.elixir_1_19
• beamMinimal27Packages.ex_doc
• beamMinimal27Packages.hex
• beamMinimal28Packages.elixir (beamMinimal28Packages.elixir_1_18)
• beamMinimal28Packages.elixir-ls
• beamMinimal28Packages.elixir_1_19
• beamMinimal28Packages.ex_doc
• beamMinimal28Packages.hex
• lexical
• mix2nix
• mobilizon
• pinchflat
• pleroma
• protoc-gen-elixir

---

Error logs: `aarch64-linux`

firezone-server

Running phase: unpackPhase
@nix { "action": "setPhase", "phase": "unpackPhase" }
unpacking source archive /nix/store/0dmj2gdpv4fdr3a09kjr8k0lilbhplaw-source/elixir
source root is elixir
Running phase: patchPhase
@nix { "action": "setPhase", "phase": "patchPhase" }
Running phase: updateAutotoolsGnuConfigScriptsPhase
@nix { "action": "setPhase", "phase": "updateAutotoolsGnuConfigScriptsPhase" }
Running phase: configurePhase
@nix { "action": "setPhase", "phase": "configurePhase" }
==> opentelemetry_semantic_conventions
Compiling 2 files (.erl)
Compiling 79 files (.ex)
Generated opentelemetry_semantic_conventions app
escript: Not an archive file
** (Mix) Could not compile dependency :otel_http, "/nix/store/972dfzqpyq29j418g3rs2qcsxrg7ajlj-rebar3-3.25.0/bin/rebar3 bare compile --paths /build/elixir/_build/prod/lib/*/ebin" command failed. Errors may have been logged above. You can recompile this dependency with "mix deps.compile otel_http --force", update it with "mix deps.update otel_http" or clean it with "mix deps.clean otel_http"

livebook

Running phase: configurePhase
@nix { "action": "setPhase", "phase": "configurePhase" }
==> earmark_parser
Compiling 2 files (.xrl)
Compiling 1 file (.yrl)
Compiling 3 files (.erl)
Compiling 47 files (.ex)
Generated earmark_parser app
==> pluggable
Compiling 4 files (.ex)
Generated pluggable app
==> decimal
Compiling 4 files (.ex)
Generated decimal app
==> mime
Compiling 1 file (.ex)
Generated mime app
==> livebook
escript: Not an archive file
** (Mix) Could not compile dependency :iso8601, "/nix/store/972dfzqpyq29j418g3rs2qcsxrg7ajlj-rebar3-3.25.0/bin/rebar3 bare compile --paths /build/source/_build/prod/lib/*/ebin" command failed. Errors may have been logged above. You can recompile this dependency with "mix deps.compile iso8601 --force", update it with "mix deps.update iso8601" or clean it with "mix deps.clean iso8601"

next-ls

==> spitfire
Compiling 2 files (.erl)
Compiling 3 files (.ex)
      warning: this clause of defp get_newlines/2 is never used
      │
 2581 │   defp get_newlines(parser, :current) do
      │        ~
      │
      └─ lib/spitfire.ex:2581:8: Spitfire.get_newlines/2
Generated spitfire app

==> mime

Compiling 1 file (.ex)

Generated mime app

==> nimble_options

Compiling 3 files (.ex)

Generated nimble_options app

==> next_ls

escript: Not an archive file

** (Mix) Could not compile dependency :gproc, "/nix/store/972dfzqpyq29j418g3rs2qcsxrg7ajlj-rebar3-3.25.0/bin/rebar3 bare compile --paths /build/source/_build/prod/lib/*/ebin" command failed. Errors may have been logged above. You can recompile this dependency with "mix deps.compile gproc --force", update it with "mix deps.update gproc" or clean it with "mix deps.clean gproc"

plausible

Generated mime app
==> x509
Compiling 25 files (.ex)
    warning: Jason.decode!/1 is undefined (module Jason is not available or is yet to be defined)
    │
  7 │     |> Jason.decode!()
    │              ~
    │
    └─ lib/x509/path_validation_test.ex:7:14: X509.PathValidationTest.all_scenarios/0
Generated x509 app

==> nimble_options

Compiling 3 files (.ex)

Generated nimble_options app

==> nimble_parsec

Compiling 4 files (.ex)

Generated nimble_parsec app

escript: Not an archive file

==> plausible

** (Mix) Could not compile dependency :gproc, "/nix/store/972dfzqpyq29j418g3rs2qcsxrg7ajlj-rebar3-3.25.0/bin/rebar3 bare compile --paths /build/source/_build/ce/lib/*/ebin" command failed. Errors may have been logged above. You can recompile this dependency with "mix deps.compile gproc --force", update it with "mix deps.update gproc" or clean it with "mix deps.clean gproc"

rabbitmq-server

/nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin/rabbitmq-diagnostics: interpreter directive changed from "#!/bin/sh" to "/nix/store/fkxvlai6grfi6nngzgp0vahi235nhkq3-bash-5.2p37/bin/sh"
/nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin/rabbitmq-env: interpreter directive changed from "#!/bin/sh -e" to "/nix/store/fkxvlai6grfi6nngzgp0vahi235nhkq3-bash-5.2p37/bin/sh -e"
/nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin/rabbitmq-plugins: interpreter directive changed from "#!/bin/sh" to "/nix/store/fkxvlai6grfi6nngzgp0vahi235nhkq3-bash-5.2p37/bin/sh"
/nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin/rabbitmq-queues: interpreter directive changed from "#!/bin/sh" to "/nix/store/fkxvlai6grfi6nngzgp0vahi235nhkq3-bash-5.2p37/bin/sh"
/nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin/rabbitmq-server: interpreter directive changed from "#!/bin/sh" to "/nix/store/fkxvlai6grfi6nngzgp0vahi235nhkq3-bash-5.2p37/bin/sh"
/nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin/rabbitmq-streams: interpreter directive changed from "#!/bin/sh" to "/nix/store/fkxvlai6grfi6nngzgp0vahi235nhkq3-bash-5.2p37/bin/sh"
/nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin/rabbitmq-upgrade: interpreter directive changed from "#!/bin/sh" to "/nix/store/fkxvlai6grfi6nngzgp0vahi235nhkq3-bash-5.2p37/bin/sh"
/nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin/rabbitmqctl: interpreter directive changed from "#!/bin/sh" to "/nix/store/fkxvlai6grfi6nngzgp0vahi235nhkq3-bash-5.2p37/bin/sh"
/nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin/vmware-rabbitmq: interpreter directive changed from "#!/bin/sh" to "/nix/store/fkxvlai6grfi6nngzgp0vahi235nhkq3-bash-5.2p37/bin/sh"
stripping (with command strip and flags -S -p) in  /nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/bin /nix/store/flq84az61mazbgpxrlyhfwidwg07y3xp-rabbitmq-server-4.0.9/sbin
shrinking RPATHs of ELF executables and libraries in /nix/store/s9qspvl73jc3gfxm5gy9hr19rihc6lv8-rabbitmq-server-4.0.9-man
checking for references to /build/ in /nix/store/s9qspvl73jc3gfxm5gy9hr19rihc6lv8-rabbitmq-server-4.0.9-man...
gzipping man pages under /nix/store/s9qspvl73jc3gfxm5gy9hr19rihc6lv8-rabbitmq-server-4.0.9-man/share/man/
patching script interpreter paths in /nix/store/s9qspvl73jc3gfxm5gy9hr19rihc6lv8-rabbitmq-server-4.0.9-man
shrinking RPATHs of ELF executables and libraries in /nix/store/daggak5as1qwa1vpikr7g62pwhqfb92h-rabbitmq-server-4.0.9-doc
checking for references to /build/ in /nix/store/daggak5as1qwa1vpikr7g62pwhqfb92h-rabbitmq-server-4.0.9-doc...
patching script interpreter paths in /nix/store/daggak5as1qwa1vpikr7g62pwhqfb92h-rabbitmq-server-4.0.9-doc
Running phase: installCheckPhase
@nix { "action": "setPhase", "phase": "installCheckPhase" }
escript: Not an archive file

sonic-pi

-- Installing: /build/source/app/server/beam/tau/priv/libsp_link.so
[ 99%] Completed 'sp_link'
[ 99%] Built target sp_link
[ 99%] Linking CXX executable sonic-pi
[100%] Built target sonic-pi
Compiling Erlang/Elixir files...
warning: the VM is running with native name encoding of latin1 which may cause Elixir to malfunction as it expects utf8. Please ensure your locale is set to UTF-8 (which can be verified by running "locale" in your shell) or set the ELIXIR_ERL_OPTIONS="+fnu" environment variable
warning: the VM is running with native name encoding of latin1 which may cause Elixir to malfunction as it expects utf8. Please ensure your locale is set to UTF-8 (which can be verified by running "locale" in your shell) or set the ELIXIR_ERL_OPTIONS="+fnu" environment variable
==> logger_file_backend
Compiling 1 file (.ex)
Generated logger_file_backend app
==> decimal
Compiling 4 files (.ex)
Generated decimal app
==> mime
Compiling 1 file (.ex)
Generated mime app
==> tau
escript: Not an archive file
** (Mix) Could not compile dependency :telemetry, "/nix/store/972dfzqpyq29j418g3rs2qcsxrg7ajlj-rebar3-3.25.0/bin/rebar3 bare compile --paths /build/source/app/server/beam/tau/_build/prod/lib/*/ebin" command failed. Errors may have been logged above. You can recompile this dependency with "mix deps.compile telemetry --force", update it with "mix deps.update telemetry" or clean it with "mix deps.clean telemetry"

[adamcstephens]

Ok, tracked down the failures to a regression in shebang patching. The fix for this is in staging already, so many erlang/elixir packages are broken until that gets to master.

[nixpkgs-ci]

Successfully created backport PR for release-25.05:

• [Backport release-25.05] elixir-ls: fix elixir stdlib code detection, elixir: fix deterministic builds and 1.17 max OTP #426433

[PedroHLC]

I'm pretty sure the patch is being applied (I copied the ./apps folder to $out through postInstall in an overrideAttrs and inspected it), yet:

{"jsonrpc":"2.0","method":"window/logMessage","params":{"message":"** (FunctionClauseError) no function clause matching in IO.chardata_to_string/1    \n    \n    The following arguments were given to IO.chardata_to_string/1:\n    \n        # 1\n        nil\n    \n    Attempted function clauses (showing 2 out of 2):\n    \n        def chardata_to_string(+string+) when -is_binary(string)-\n        def chardata_to_string(+list+) when -is_list(list)-\n    \n    (elixir 1.14.5) lib/io.ex:670: IO.chardata_to_string/1\n    (elixir 1.14.5) lib/file.ex:219: File.exists?/2\n    (language_server 0.28.1) lib/language_server.ex:146: ElixirLS.LanguageServer.check_elixir_sources/0\n    (language_server 0.28.1) lib/language_server.ex:63: ElixirLS.LanguageServer.main/0\n    (elixir 1.14.5) lib/code.ex:1260: Code.require_file/2","type":2}}

Is someone else observing the same? (Nixpkgs 2baf8e1658cba84a032c3a8befb1e7b06629242a)

[PedroHLC]

Ok, this line is weird.

By default, it will use hex to fetch the source again, and run with that instead of anything from Nixpkgs' package.

With ELS_LOCAL=1 it will run the interpreter in the project in $store/libexec/../, which will fail.

What exactly are we attempting to do here?

[adamcstephens]

This package needs more changes on top of what is in this PR. This was a first pass at cleanup, but this package is indeed weird in that it's not really a package but a set of wrapper scripts. Ideally we properly package it and set ELS_LOCAL so it uses code from the store instead of downloading. Until then I wouldn't expect setting that env var to work.

I've used these changes without issues though. Do you have a reproducer?

[PedroHLC]

I've used these changes without issues though. Do you have a reproducer?

I'm more curious what impurity made it work for you, since there is no codepath that uses the .beam built here, it always uses the one re-downloaded into the mix home path, without the 1216.patch we need.

[adamcstephens]

I understand the problem now, but it's still not clear to me why it worked on my machine.

Anyway, can you try this PR? #427805