Merge pull request #73803 from andir/buildRustCrate-lib-output

buildRustCrate: add lib output

nixos/doc/manual/release-notes/rl-2003.xml

@@ -193,6 +193,12 @@
       The aforementioned option was added this release.
     </para>
    </listitem>
+   <listitem>
+    <para>
+      The <literal>buildRustCrate</literal> infrastructure now produces <literal>lib</literal> outputs in addition to the <literal>out</literal> output.
+      This has led to drastically reduced closed sizes for some rust crates since development dependencies are now in the <literal>lib</literal> output.
+    </para>
+   </listitem>
   </itemizedlist>
  </section>
 

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

@@ -91,18 +91,18 @@
 
     echo "$EXTRA_LINK_SEARCH" | while read i; do
        if [[ ! -z "$i" ]]; then
-         for lib in $i; do
-           echo "-L $lib" >> target/link
-           L=$(echo $lib | sed -e "s#$(pwd)/target/build#$out/lib#")
+         for library in $i; do
+           echo "-L $library" >> target/link
+           L=$(echo $library | sed -e "s#$(pwd)/target/build#$lib/lib#")
            echo "-L $L" >> target/link.final
          done
        fi
     done
     echo "$EXTRA_LINK" | while read i; do
        if [[ ! -z "$i" ]]; then
-         for lib in $i; do
-           echo "-l $lib" >> target/link
-           echo "-l $lib" >> target/link.final
+         for library in $i; do
+           echo "-l $library" >> target/link
+           echo "-l $library" >> target/link.final
          done
        fi
     done

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

@@ -22,9 +22,9 @@ let
           else
             extern;
         in (if lib.lists.any (x: x == "lib") dep.crateType then
-           " --extern ${name}=${dep.out}/lib/lib${extern}-${dep.metadata}.rlib"
+           " --extern ${name}=${dep.lib}/lib/lib${extern}-${dep.metadata}.rlib"
          else
-           " --extern ${name}=${dep.out}/lib/lib${extern}-${dep.metadata}${stdenv.hostPlatform.extensions.sharedLibrary}")
+           " --extern ${name}=${dep.lib}/lib/lib${extern}-${dep.metadata}${stdenv.hostPlatform.extensions.sharedLibrary}")
       ) dependencies);
 
     echo_build_heading = colors: ''
@@ -96,12 +96,12 @@ stdenv.mkDerivation (rec {
     buildInputs = (crate.buildInputs or []) ++ buildInputs_;
     dependencies =
       builtins.map
-        (dep: dep.override { rust = rust; release = release; verbose = verbose; crateOverrides = crateOverrides; })
+        (dep: lib.getLib (dep.override { rust = rust; release = release; verbose = verbose; crateOverrides = crateOverrides; }))
         dependencies_;
 
     buildDependencies =
       builtins.map
-        (dep: dep.override { rust = rust; release = release; verbose = verbose; crateOverrides = crateOverrides; })
+        (dep: lib.getLib (dep.override { rust = rust; release = release; verbose = verbose; crateOverrides = crateOverrides; }))
         buildDependencies_;
 
     completeDeps = lib.lists.unique (dependencies ++ lib.lists.concatMap (dep: dep.completeDeps) dependencies);
@@ -160,6 +160,9 @@ stdenv.mkDerivation (rec {
     };
     installPhase = installCrate crateName metadata;
 
+    outputs = [ "out" "lib" ];
+    outputDev = [ "lib" ];
+
 } // extraDerivationAttrs
 )) {
   rust = rustc;

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

@@ -1,24 +1,26 @@
 crateName: metadata:
 ''
   runHook preInstall
-  mkdir -p $out
+  # always create $out even if we do not have binaries. We are detecting binary targets during compilation, if those are missing there is no way to only have $lib
+  mkdir $out
   if [[ -s target/env ]]; then
-    cp target/env $out/env
+    mkdir -p $lib
+    cp target/env $lib/env
   fi
   if [[ -s target/link.final ]]; then
-    mkdir -p $out/lib
-    cp target/link.final $out/lib/link
+    mkdir -p $lib/lib
+    cp target/link.final $lib/lib/link
   fi
   if [[ "$(ls -A target/lib)" ]]; then
-    mkdir -p $out/lib
-    cp target/lib/* $out/lib #*/
-    for lib in $out/lib/*.so $out/lib/*.dylib; do #*/
-      ln -s $lib $(echo $lib | sed -e "s/-${metadata}//")
+    mkdir -p $lib/lib
+    cp target/lib/* $lib/lib #*/
+    for library in $lib/lib/*.so $lib/lib/*.dylib; do #*/
+      ln -s $library $(echo $library | sed -e "s/-${metadata}//")
     done
   fi
   if [[ "$(ls -A target/build)" ]]; then # */
-    mkdir -p $out/lib
-    cp -r target/build/* $out/lib # */
+    mkdir -p $lib/lib
+    cp -r target/build/* $lib/lib # */
   fi
   if [[ -d target/bin ]]; then
     if [[ "$(ls -A target/bin)" ]]; then