Improve library loading (#8921)

- Move exactly matching versions to the head of the list when using the
  package manager to get compatible versions, to avoid loading other
  versions of libraries when the requested version exists.

Author: perost

OMCompiler/Compiler/FrontEnd/ClassLoader.mo

@@ -144,6 +144,14 @@ protected
   Boolean isDir, impactOK;
   Option<Absyn.Class> cl;
   list<String> versionsThatProvideTheWanted, commands, versions;
+  list<String> exact_versions, compatible_versions;
+
+  function isExactVersion
+    input String version;
+    input String requestedVersion;
+    output Boolean exact = Util.stringStartsWith(requestedVersion, version) and
+                           not Util.stringContainsChar(version, "-");
+  end isExactVersion;
 algorithm
   if not requireExactVersion then
     if listEmpty(prios) then
@@ -155,12 +163,20 @@ algorithm
         versionsThatProvideTheWanted :=
           PackageManagement.versionsThatProvideTheWanted(id, v, printError = false);
 
+        (exact_versions, compatible_versions) :=
+          List.splitOnTrue(versionsThatProvideTheWanted, function isExactVersion(requestedVersion = v));
+        versionsThatProvideTheWanted := listAppend(exact_versions, compatible_versions);
+
         if listEmpty(versionsThatProvideTheWanted) then
           versions := v :: versions;
         else
           versions := listAppend(versionsThatProvideTheWanted, versions);
         end if;
       end for;
+
+      if listEmpty(versions) then
+        versions := prios;
+      end if;
     end if;
   else
     versions := prios;