Bring back require $file-name;

Added an extra method to CompUnit::Repository for loading a module from a given
file name. The exact use cases for this are unclear, but it's speced and it
feels like an appropriate low level tool for extreme situations.

In any case it's quite separate from normal module loading, so it can be removed
easily in case we decide that it has to go.

src/core/CompUnit/Repository.pm

@@ -11,6 +11,11 @@ role CompUnit::Repository {
         returns CompUnit:D
         { ... }
 
+    # Just load the file and return a CompUnit object representing it.
+    method load(Str:D $file)
+        returns CompUnit:D
+        { ... }
+
     # Returns the CompUnit objects describing all of the compilation
     # units that have been loaded by this repository in the current
     # process.

src/core/CompUnitRepo.pm

@@ -77,14 +77,22 @@ RAKUDO_MODULE_DEBUG("Looking in $spec for $name")
             }
         }
         else {
-            return $*REPO.need(
-                CompUnit::DependencySpecification.new(
-                    :short-name($module_name),
-                    :auth-matcher(%opts<auth>),
-                    :version-matcher(%opts<ver>),
-                ),
-                GLOBALish,
-                :$line,
+            return (
+                $file
+                ?? $*REPO.load(
+                    $file,
+                    GLOBALish,
+                    :$line
+                )
+                !! $*REPO.need(
+                    CompUnit::DependencySpecification.new(
+                        :short-name($module_name),
+                        :auth-matcher(%opts<auth>),
+                        :version-matcher(%opts<ver>),
+                    ),
+                    GLOBALish,
+                    :$line,
+                )
             ).unit;
         }
 #        elsif $file {

src/core/CompUnitRepo/Locally.pm

@@ -40,7 +40,11 @@ role CompUnitRepo::Locally {
     )
         returns CompUnit:D
     {
-        my @candidates = self.candidates($spec.short-name, :auth($spec.auth-matcher), :ver($spec.version-matcher));
+        my @candidates = self.candidates(
+            $spec.short-name,
+            :auth($spec.auth-matcher),
+            :ver($spec.version-matcher),
+        );
         if @candidates {
             @candidates[0].load(GLOBALish, :$line);
             return @candidates[0];
@@ -49,6 +53,16 @@ role CompUnitRepo::Locally {
         nqp::die("Could not find $spec in:\n" ~ $*REPO.repo-chain.map(*.Str).join("\n").indent(4));
     }
 
+    method load(Str:D $file, \GLOBALish is raw = Any, :$line) returns CompUnit:D {
+        my @candidates = self.candidates($file, :file($file));
+        if @candidates {
+            @candidates[0].load(GLOBALish, :$line);
+            return @candidates[0];
+        }
+        return self.next-repo.load($file, :$line) if self.next-repo;
+        nqp::die("Could not find $file in:\n" ~ $*REPO.repo-chain.map(*.Str).join("\n").indent(4));
+    }
+
     method loaded() returns Iterable {
         return ();
     }