test_provide_builtins failing on macOS when matching against nix --version output

[lilyball]

Describe the bug

Building rnix-lsp v0.2.3 against recent nixpkgs (NixOS/nixpkgs@77fda7f) on macOS fails with

thread 'lookup::tests::test_provide_builtins' panicked at 'called `Option::unwrap()` on a `None` value', src/lookup.rs:185:48

It looks like it's failing to run a regex on the nix --version output:

rnix-lsp/src/lookup.rs

Lines 174 to 185 in 1665bc6

	let nixver = process::Command::new("nix").args(&["--version"]).output();
	// `nix __dump-builtins` is only supported on `nixUnstable` a.k.a. Nix 2.4.
	// Thus, we have to check if this is actually available. If not, `rnix-lsp` will fall
	// back to a hard-coded list of builtins which is missing additional info such as documentation
	// or parameter names though.
	match nixver {
	Ok(out) => {
	match str::from_utf8(&out.stdout) {
	Ok(v) => {
	let re = regex::Regex::new(r"^nix \(Nix\) (?P<major>\d)\.(?P<minor>\d).*").unwrap();
	let m = re.captures(v).unwrap();

Interestingly, cache.nixos.org has binary artifacts for it, though this seems intermittent (on a slightly older revision of nixpkgs, cache.nixos.org had binary artifacts for aarch64-apple-darwin but not for x86_64-apple-darwin; for the referenced version it has artifacts for both. The failure occurs on both architectures though).

Build log

> nix log /nix/store/ngwa65ypzm6gzpgq671fk50iv77bi2a5-rnix-lsp-0.2.3.drv
@nix { "action": "setPhase", "phase": "unpackPhase" }
unpacking sources
unpacking source archive /nix/store/dav99d7fcksybhpfpyy9qmxz1c8r5b07-source
source root is source
Executing cargoSetupPostUnpackHook
unpacking source archive /nix/store/6hgjnhc7qdswn9khscmqmkzkpz2bjsic-rnix-lsp-0.2.3-vendor.tar.gz
Finished cargoSetupPostUnpackHook
@nix { "action": "setPhase", "phase": "patchPhase" }
patching sources
Executing cargoSetupPostPatchHook
Validating consistency between /private/tmp/nix-build-rnix-lsp-0.2.3.drv-0/source//Cargo.lock and /private/tmp/nix-build-rnix-lsp-0.2.3.drv-0/rnix-lsp-0.2.3-vendor.tar.gz/Cargo.lock
Finished cargoSetupPostPatchHook
@nix { "action": "setPhase", "phase": "configurePhase" }
configuring
@nix { "action": "setPhase", "phase": "buildPhase" }
building
Executing cargoBuildHook
++ env CC_x86_64-apple-darwin=/nix/store/a2sz5pfcilnp7hw9hhqipvs3rvq3s59v-clang-wrapper-11.1.0/bin/cc CXX_x86_64-apple-darwin=/nix/store/a2sz5pfcilnp7hw9hhqipvs3rvq3s59v-clang-wrapper-11.1.0/bin/c++ CC_x86_64-apple-darwin=/nix/store/a2sz5pfcilnp7hw9hhqipvs3rvq3s59v-clang-wrapper-11.1.0/bin/cc CXX_x86_64-apple-darwin=/nix/store/a2sz5pfcilnp7hw9hhqipvs3rvq3s59v-clang-wrapper-11.1.0/bin/c++ cargo build -j 16 --target x86_64-apple-darwin --frozen --release
   Compiling proc-macro2 v1.0.29
   Compiling unicode-xid v0.2.2
   Compiling syn v1.0.75
   Compiling serde_derive v1.0.130
   Compiling autocfg v1.0.1
   Compiling serde v1.0.130
   Compiling memchr v2.4.1
   Compiling cfg-if v1.0.0
   Compiling libc v0.2.101
   Compiling log v0.4.14
   Compiling lazy_static v1.4.0
   Compiling crossbeam-utils v0.8.5
   Compiling ryu v1.0.5
   Compiling serde_json v1.0.67
   Compiling regex-syntax v0.6.25
   Compiling tinyvec_macros v0.1.0
   Compiling itoa v0.4.8
   Compiling matches v0.1.9
   Compiling percent-encoding v2.1.0
   Compiling same-file v1.0.6
   Compiling rustc-hash v1.1.0
   Compiling hashbrown v0.9.1
   Compiling unicode-bidi v0.3.6
   Compiling once_cell v1.9.0
   Compiling cfg-if v0.1.10
   Compiling fnv v1.0.7
   Compiling bitflags v1.3.2
   Compiling countme v2.0.4
   Compiling unicode-width v0.1.9
   Compiling smol_str v0.1.18
   Compiling strsim v0.8.0
   Compiling vec_map v0.8.2
   Compiling ansi_term v0.12.1
   Compiling humantime v2.1.0
   Compiling termcolor v1.1.2
   Compiling tinyvec v1.3.1
   Compiling form_urlencoded v1.0.1
   Compiling walkdir v2.3.2
   Compiling crossbeam-utils v0.6.6
   Compiling thread_local v1.1.3
   Compiling textwrap v0.11.0
   Compiling num-traits v0.2.14
   Compiling memoffset v0.6.4
   Compiling crossbeam-channel v0.3.9
   Compiling crossbeam-channel v0.5.1
   Compiling unicode-normalization v0.1.19
   Compiling aho-corasick v0.7.18
   Compiling bstr v0.2.17
   Compiling atty v0.2.14
   Compiling dirs-sys v0.3.6
   Compiling quote v1.0.9
   Compiling clap v2.34.0
   Compiling dirs v3.0.2
   Compiling idna v0.2.3
   Compiling regex v1.5.4
   Compiling cbitset v0.2.0
   Compiling globset v0.4.8
   Compiling env_logger v0.9.0
   Compiling ignore v0.4.18
   Compiling serde_repr v0.1.7
   Compiling text-size v1.1.0
   Compiling url v2.2.2
   Compiling rowan v0.12.6
   Compiling rnix v0.10.1
   Compiling lsp-types v0.89.2
   Compiling lsp-server v0.5.2
   Compiling nixpkgs-fmt-rnix v1.2.0
   Compiling rnix-lsp v0.2.3 (/private/tmp/nix-build-rnix-lsp-0.2.3.drv-0/source)
    Finished release [optimized] target(s) in 48.20s
Executing cargoInstallPostBuildHook
Finished cargoInstallPostBuildHook
Finished cargoBuildHook
@nix { "action": "setPhase", "phase": "checkPhase" }
running tests
Executing cargoCheckHook
++ cargo test -j 16 --release --target x86_64-apple-darwin --frozen -- --test-threads=16
   Compiling rnix-lsp v0.2.3 (/private/tmp/nix-build-rnix-lsp-0.2.3.drv-0/source)
    Finished release [optimized] target(s) in 2.72s
     Running unittests (target/x86_64-apple-darwin/release/deps/rnix_lsp-fa2f5f71aacc1669)

running 17 tests
test lookup::tests::test_provide_builtins_non_mac ... ignored
test lookup::tests::test_builtin_fallback ... ok
test lookup::tests::test_builtin_from_dump_builtins ... ok
test utils::tests::test_get_offset_from_nix_expr ... ok
test utils::tests::test_lookup_pos_in_expr ... ok
test utils::tests::test_ident_attr_path ... ok
test utils::tests::test_offset_across_multiple_lines ... ok
test utils::tests::test_lookup_pos_out_of_range ... ok
test utils::tests::test_find_ident ... ok
test utils::tests::test_inherit_ident ... ok
test utils::tests::test_offset_too_large - should panic ... ok
test lookup::tests::test_ident_traverse_attr_path ... ok
test lookup::tests::test_suggest_let_in_variable ... ok
test lookup::tests::test_find_inherit_scope ... ok
test utils::tests::test_populate_scope ... ok
test utils::tests::test_populate_scope_legacy_let ... ok
test lookup::tests::test_provide_builtins ... FAILED

failures:

---- lookup::tests::test_provide_builtins stdout ----
thread 'lookup::tests::test_provide_builtins' panicked at 'called `Option::unwrap()` on a `None` value', src/lookup.rs:185:48


failures:
    lookup::tests::test_provide_builtins

test result: FAILED. 15 passed; 1 failed; 1 ignored; 0 measured; 0 filtered out; finished in 0.09s

error: test failed, to rerun pass '--bin rnix-lsp'

Steps to reproduce

Steps to reproduce the behavior:

1. nix build --rebuild github:NixOS/nixpkgs/77fda7f672726e1a95c8cd200f27bccfc86c870b#rnix-lsp

Expected behavior

It should compile.

Additional context

• Operating system: macOS 12 (both x86_64-apple-darwin and aarch64-apple-darwin)

[lilyball]

I can't reproduce this in a nix develop shell or with nix-shell. If I patch the source to print the nix --version output and run that through nix build I get v = "".

[lilyball]

Here's the whole nixver result struct, which is quite interesting:

rnix-lsp> [src/lookup.rs:175] &nixver = Ok(
rnix-lsp>     Output {
rnix-lsp>         status: ExitStatus(
rnix-lsp>             unix_wait_status(
rnix-lsp>                 6,
rnix-lsp>             ),
rnix-lsp>         ),
rnix-lsp>         stdout: "",
rnix-lsp>         stderr: "libc++abi: terminating with uncaught exception of type nix::SysError: \u{1b}[31;1merror:\u{1b}[0m getting status of \u{1b}[35;1m/System/Library/LaunchDaemons/com.apple.oahd.plist\u{1b}[0m: \u{1b}[35;1mOperation not permitted\u{1b}[0m\n",
rnix-lsp>     },
rnix-lsp> )

[lilyball]

If this is a sandboxing issue, that explains why it doesn't reproduce in nix develop or nix-shell. What I don't get is why this still occurs with nix --no-sandbox build. Or why nix is attempting to get the file metadata of /System/Library/LaunchDaemons/com.apple.oahd.plist.

[lilyball]

I filed NixOS/nix#5884 about nix --version failing in the macOS sandbox.