buildRustCrate: support cargo:: invocation syntax for build script outputs

In order to allow for the new `cargo::` prefix for build script outputs
we have to adjust the configure-crate bash scripts in buildRustCrate to
properly parse the new additional syntax.

These changes don't affect existing build scripts configured with the
old `cargo:` prefix.

For more information, see https://doc.rust-lang.org/cargo/reference/build-scripts.html#outputs-of-the-build-script

pkgs/build-support/rust/build-rust-crate/configure-crate.nix

@@ -198,13 +198,16 @@ in ''
      )
 
      set +e
-     EXTRA_BUILD=$(sed -n "s/^cargo:rustc-flags=\(.*\)/\1/p" target/build/${crateName}.opt | tr '\n' ' ' | sort -u)
+     # We want to support the new prefix invocation syntax which uses two colons
-     EXTRA_FEATURES=$(sed -n "s/^cargo:rustc-cfg=\(.*\)/--cfg \1/p" target/build/${crateName}.opt | tr '\n' ' ')
+     # See https://doc.rust-lang.org/cargo/reference/build-scripts.html#outputs-of-the-build-script
-     EXTRA_LINK_ARGS=$(sed -n "s/^cargo:rustc-link-arg=\(.*\)/-C link-arg=\1/p" target/build/${crateName}.opt | tr '\n' ' ')
+
-     EXTRA_LINK_ARGS_BINS=$(sed -n "s/^cargo:rustc-link-arg-bins=\(.*\)/-C link-arg=\1/p" target/build/${crateName}.opt | tr '\n' ' ')
+     EXTRA_BUILD=$(sed -n "s/^cargo::\{0,1\}rustc-flags=\(.*\)/\1/p" target/build/${crateName}.opt | tr '\n' ' ' | sort -u)
-     EXTRA_LINK_ARGS_LIB=$(sed -n "s/^cargo:rustc-link-arg-lib=\(.*\)/-C link-arg=\1/p" target/build/${crateName}.opt | tr '\n' ' ')
+     EXTRA_FEATURES=$(sed -n "s/^cargo::\{0,1\}rustc-cfg=\(.*\)/--cfg \1/p" target/build/${crateName}.opt | tr '\n' ' ')
-     EXTRA_LINK_LIBS=$(sed -n "s/^cargo:rustc-link-lib=\(.*\)/\1/p" target/build/${crateName}.opt | tr '\n' ' ')
+     EXTRA_LINK_ARGS=$(sed -n "s/^cargo::\{0,1\}rustc-link-arg=\(.*\)/-C link-arg=\1/p" target/build/${crateName}.opt | tr '\n' ' ')
-     EXTRA_LINK_SEARCH=$(sed -n "s/^cargo:rustc-link-search=\(.*\)/\1/p" target/build/${crateName}.opt | tr '\n' ' ' | sort -u)
+     EXTRA_LINK_ARGS_BINS=$(sed -n "s/^cargo::\{0,1\}rustc-link-arg-bins=\(.*\)/-C link-arg=\1/p" target/build/${crateName}.opt | tr '\n' ' ')
+     EXTRA_LINK_ARGS_LIB=$(sed -n "s/^cargo::\{0,1\}rustc-link-arg-lib=\(.*\)/-C link-arg=\1/p" target/build/${crateName}.opt | tr '\n' ' ')
+     EXTRA_LINK_LIBS=$(sed -n "s/^cargo::\{0,1\}rustc-link-lib=\(.*\)/\1/p" target/build/${crateName}.opt | tr '\n' ' ')
+     EXTRA_LINK_SEARCH=$(sed -n "s/^cargo::\{0,1\}rustc-link-search=\(.*\)/\1/p" target/build/${crateName}.opt | tr '\n' ' ' | sort -u)
 
      # We want to read part of every line that has cargo:rustc-env= prefix and
      # export it as environment variables. This turns out tricky if the lines
@@ -217,14 +220,15 @@ in ''
      #
      _OLDIFS="$IFS"
      IFS=$'\n'
-     for env in $(sed -n "s/^cargo:rustc-env=\(.*\)/\1/p" target/build/${crateName}.opt); do
+     for env in $(sed -n "s/^cargo::\{0,1\}rustc-env=\(.*\)/\1/p" target/build/${crateName}.opt); do
        export "$env"
      done
      IFS="$_OLDIFS"
 
      CRATENAME=$(echo ${crateName} | sed -e "s/\(.*\)-sys$/\U\1/" -e "s/-/_/g")
-     grep -P "^cargo:(?!(rustc-|warning=|rerun-if-changed=|rerun-if-env-changed))" target/build/${crateName}.opt \
+     grep -P "^cargo:(?!:?(rustc-|warning=|rerun-if-changed=|rerun-if-env-changed))" target/build/${crateName}.opt \
-       | awk -F= "/^cargo:/ { sub(/^cargo:/, \"\", \$1); gsub(/-/, \"_\", \$1); print \"export \" toupper(\"DEP_$(echo $CRATENAME)_\" \$1) \"=\" \"\\\"\"\$2\"\\\"\" }" > target/env
+       | awk -F= "/^cargo::metadata=/ {  gsub(/-/, \"_\", \$2); print \"export \" toupper(\"DEP_$(echo $CRATENAME)_\" \$2) \"=\" \"\\\"\"\$3\"\\\"\"; next }
+                  /^cargo:/ { sub(/^cargo::?/, \"\", \$1); gsub(/-/, \"_\", \$1); print \"export \" toupper(\"DEP_$(echo $CRATENAME)_\" \$1) \"=\" \"\\\"\"\$2\"\\\"\"; next }" > target/env
      set -e
   fi
   runHook postConfigure

pkgs/build-support/rust/build-rust-crate/test/default.nix

@@ -421,6 +421,53 @@ let
         buildDependencies = [ depCrate ];
         dependencies = [ depCrate ];
       };
+      # Support new invocation prefix for build scripts `cargo::`
+      # https://doc.rust-lang.org/cargo/reference/build-scripts.html#outputs-of-the-build-script
+      buildScriptInvocationPrefix = let
+        depCrate = buildRustCrate: mkCrate buildRustCrate {
+          crateName = "bar";
+          src = mkFile "build.rs" ''
+              fn main() {
+                // Old invocation prefix
+                // We likely won't see be mixing these syntaxes in the same build script in the wild.
+                println!("cargo:key_old=value_old");
+
+                // New invocation prefix
+                println!("cargo::metadata=key=value");
+                println!("cargo::metadata=key_complex=complex(value)");
+              }
+          '';
+        };
+      in {
+        crateName = "foo";
+        src = symlinkJoin {
+          name = "build-script-and-main-invocation-prefix";
+          paths = [
+            (mkFile  "src/main.rs" ''
+              const BUILDFOO: &'static str = env!("BUILDFOO");
+
+              #[test]
+              fn build_foo_check() { assert!(BUILDFOO == "yes(check)"); }
+
+              fn main() { }
+            '')
+            (mkFile  "build.rs" ''
+              use std::env;
+              fn main() {
+                assert!(env::var_os("DEP_BAR_KEY_OLD").expect("metadata key 'key_old' not set in dependency") == "value_old");
+                assert!(env::var_os("DEP_BAR_KEY").expect("metadata key 'key' not set in dependency") == "value");
+                assert!(env::var_os("DEP_BAR_KEY_COMPLEX").expect("metadata key 'key_complex' not set in dependency") == "complex(value)");
+
+                println!("cargo::rustc-env=BUILDFOO=yes(check)");
+              }
+            '')
+          ];
+        };
+        buildDependencies = [ (depCrate buildPackages.buildRustCrate) ];
+        dependencies = [ (depCrate buildRustCrate) ];
+        buildTests = true;
+        expectedTestOutputs = [ "test build_foo_check ... ok" ];
+      };
       # Regression test for https://github.com/NixOS/nixpkgs/issues/74071
       # Whenevever a build.rs file is generating files those should not be overlayed onto the actual source dir
       buildRsOutDirOverlay = {