lib/modules: introduce setDefaultModuleLocation

Wraps a module with a default location for reporting errors.

lib/default.nix

@@ -111,8 +111,8 @@ let
       cleanSource sourceByRegex sourceFilesBySuffices
       commitIdFromGitRepo cleanSourceWith pathHasContext
       canCleanSource pathIsRegularFile pathIsGitRepo;
-    inherit (self.modules) evalModules unifyModuleSyntax
-      applyIfFunction mergeModules
+    inherit (self.modules) evalModules setDefaultModuleLocation
+      unifyModuleSyntax applyIfFunction mergeModules
       mergeModules' mergeOptionDecls evalOptionValue mergeDefinitions
       pushDownProperties dischargeProperties filterOverrides
       sortProperties fixupOptionType mkIf mkAssert mkMerge mkOverride

lib/modules.nix

@@ -334,6 +334,10 @@ rec {
     in modulesPath: initialModules: args:
       filterModules modulesPath (collectStructuredModules unknownModule "" initialModules args);
 
+  /* Wrap a module with a default location for reporting errors. */
+  setDefaultModuleLocation = file: m:
+    { _file = file; imports = [ m ]; };
+
   /* Massage a module into canonical form, that is, a set consisting
      of ‘options’, ‘config’ and ‘imports’ attributes. */
   unifyModuleSyntax = file: key: m:
@@ -534,11 +538,9 @@ rec {
      correspond to the definition of 'loc' in 'opt.file'. */
   mergeOptionDecls =
    let
-    packSubmodule = file: m:
-      { _file = file; imports = [ m ]; };
     coerceOption = file: opt:
-      if isFunction opt then packSubmodule file opt
-      else packSubmodule file { options = opt; };
+      if isFunction opt then setDefaultModuleLocation file opt
+      else setDefaultModuleLocation file { options = opt; };
    in loc: opts:
     foldl' (res: opt:
       let t  = res.type;
@@ -568,7 +570,7 @@ rec {
 
           getSubModules = opt.options.type.getSubModules or null;
           submodules =
-            if getSubModules != null then map (packSubmodule opt._file) getSubModules ++ res.options
+            if getSubModules != null then map (setDefaultModuleLocation opt._file) getSubModules ++ res.options
             else if opt.options ? options then map (coerceOption opt._file) options' ++ res.options
             else res.options;
         in opt.options // res //