testers.hasPkgConfigModules: Optionally check each module's version

pkgs/build-support/testers/hasPkgConfigModules/tester.nix

@@ -5,12 +5,14 @@
 { package,
   moduleNames ? package.meta.pkgConfigModules,
   testName ? "check-pkg-config-${lib.concatStringsSep "-" moduleNames}",
+  version ? package.version or null,
+  versionCheck ? false,
 }:
 
 runCommand testName {
     nativeBuildInputs = [ pkg-config ];
     buildInputs = [ package ];
-    inherit moduleNames;
+    inherit moduleNames version versionCheck;
     meta = {
       description = "Test whether ${package.name} exposes pkg-config modules ${lib.concatStringsSep ", " moduleNames}.";
     }
@@ -32,14 +34,20 @@ runCommand testName {
   } ''
     touch "$out"
     notFound=0
+    versionMismatch=0
     for moduleName in $moduleNames; do
       echo "checking pkg-config module $moduleName in $buildInputs"
       set +e
-      version="$($PKG_CONFIG --modversion $moduleName)"
+      moduleVersion="$($PKG_CONFIG --modversion $moduleName)"
       r=$?
       set -e
       if [[ $r = 0 ]]; then
-        echo "✅ pkg-config module $moduleName exists and has version $version"
+        if [[ "$moduleVersion" == "$version" ]]; then
+          echo "✅ pkg-config module $moduleName exists and has version $moduleVersion"
+        else
+          echo "❌ pkg-config module $moduleName exists and has version $moduleVersion when $version was expected"
+          ((versionMismatch+=1))
+        fi
         printf '%s\t%s\n' "$moduleName" "$version" >> "$out"
       else
         echo "❌ pkg-config module $moduleName was not found"
@@ -47,10 +55,16 @@ runCommand testName {
       fi
     done
 
+    if [[ $notFound -eq 0 ]] && ([[ $versionMismatch -eq 0 ]] || [[ "$versionCheck" == false ]]); then
+      exit 0
+    fi
     if [[ $notFound -ne 0 ]]; then
       echo "$notFound modules not found"
       echo "These modules were available in the input propagation closure:"
       $PKG_CONFIG --list-all
-      exit 1
     fi
+    if [[ $versionMismatch -ne 0 ]]; then
+      echo "$versionMismatch version mismatches"
+    fi
+    exit 1
   ''