QL: resolve imports across qlpacks

ql/src/codeql_ql/ast/Ast.qll

@@ -2143,7 +2143,7 @@ module YAML {
       exists(YAMLEntry entry |
         entry.isRoot() and
         entry.getKey().getQualifiedName() = name and
-        result = entry.getValue().getValue() and
+        result = entry.getValue().getValue().trim() and
         entry.getLocation().getFile() = file
       )
     }
@@ -2190,6 +2190,13 @@ module YAML {
       )
     }
 
+    /**
+     * Gets a QLPack that this QLPack depends on.
+     */
+    QLPack getADependency() {
+      exists(string name | hasDependency(name, _) | result.getName().replaceAll("-", "/") = name)
+    }
+
     Location getLocation() {
       // hacky, just pick the first node in the file.
       result =

ql/src/codeql_ql/ast/internal/Module.qll

@@ -100,8 +100,10 @@ private predicate resolveQualifiedName(Import imp, ContainerOrModule m, int i) {
       exists(Container c, Container parent |
         // should ideally look at `qlpack.yml` files
         parent = imp.getLocation().getFile().getParentContainer+() and
-        exists(parent.getFile("qlpack.yml")) and
+        exists(YAML::QLPack pack |
-        c.getParentContainer() = parent and
+          pack.getFile().getParentContainer() = parent and
+          c.getParentContainer() = pack.getADependency*().getFile().getParentContainer()
+        ) and
         q = m.getName()
       |
         m = TFile(c)