Fix positioning of cargoExtraArgs in craneLib.cargoNextest (#678)

Both `cargo nextest run` and `cargo llvm-cov` do not place any cargo
options/flags right behind `cargo <HERE> ...`. All cargo related flags
can be added to the `cargoNextestExtraArgs` attribute. [Issue #675]

After altering `checkPhaseCargoCommand` to use one of two explicit
command strings inside if/else blocks, it is no longer necessary to
default `cmd` to an empty value when `withLlvmCov` is set to `true`.

---------

Co-authored-by: Ivan Petkov <ivanppetkov@gmail.com>

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Fixed
 * Fixed vendoring dependencies from an alternative registry which they
   themselves have dependencies on crates from _other_ registries.
+* Fixed `cargoNextest`'s positioning of `cargoExtraArgs` to form a valid command
+  invocation when specified.
 
 ## [0.18.0] - 2024-07-05
 

docs/API.md

@@ -624,6 +624,7 @@ Except where noted below, all derivation attributes are delegated to
 * `cargoNextestExtraArgs`: additional flags to be passed in the nextest invocation
   (e.g. specifying a profile)
   - Default value: `""`
+  - Note that all flags from `cargo test` are supported.
 * `partitions`: The number of separate nextest partitions to run. Useful if the
   test suite takes a long time and can be parallelized across multiple build
   nodes.

lib/cargoNextest.nix

@@ -27,7 +27,7 @@ let
     "withLlvmCov"
   ];
 
-  mkUpdatedArgs = { cmd ? lib.optionalString (!withLlvmCov) "run", extraSuffix ? "", moreArgs ? "", withLlvmCov }: args // {
+  mkUpdatedArgs = { cmd ? "run", extraSuffix ? "", moreArgs ? "", withLlvmCov }: args // {
     inherit cargoArtifacts;
     pnameSuffix = "-nextest${extraSuffix}";
     doCheck = args.doCheck or true;
@@ -44,10 +44,11 @@ let
     '';
 
     checkPhaseCargoCommand = ''
-      cargo ${cargoExtraArgs} \
-        ${lib.optionalString withLlvmCov "llvm-cov ${cargoLlvmCovExtraArgs}"} \
-        nextest ${cmd} ''${CARGO_PROFILE:+--cargo-profile $CARGO_PROFILE} \
-          ${cargoNextestExtraArgs} ${moreArgs}
+      ${if withLlvmCov
+        then "cargo llvm-cov nextest ${cargoLlvmCovExtraArgs}"
+        else "cargo nextest ${cmd}"} \
+      ''${CARGO_PROFILE:+--cargo-profile $CARGO_PROFILE} \
+      ${cargoExtraArgs} ${cargoNextestExtraArgs} ${moreArgs}
     '';
 
     nativeBuildInputs = (args.nativeBuildInputs or [ ])