···

       
95
       
95
       
 
       
A portion of the configuration tree which is elided from `config`.

     

       
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96
       
 
       


     

       
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97
       
 
       
<!-- TODO: when markdown migration is complete, make _module docs visible again and reference _module docs. Maybe move those docs into this chapter? -->

     

       
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+
       


     

       
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+
       
#### `_type` {#module-system-lib-evalModules-return-value-_type}

     

       
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100
       
+
       


     

       
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+
       
A nominal type marker, always `"configuration"`.

     

       
102
       
102
       
+
       


     

       
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103
       
+
       
#### `configurationClass` {#module-system-lib-evalModules-return-value-_configurationClass}

     

       
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104
       
+
       


     

       
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105
       
+
       
Equal to the [`class` parameter](#module-system-lib-evalModules-param-class).

     

···

       
220
       
220
       
 
       
              within a configuration, but can be used in module imports.

     

       
221
       
221
       
 
       
            '';

     

       
222
       
222
       
 
       
          };

     

       
223
       
223
       
-
       


     

       
224
       
224
       
-
       
          _module.class = mkOption {

     

       
225
       
225
       
-
       
            readOnly = true;

     

       
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226
       
-
       
            internal = true;

     

       
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-
       
            description = lib.mdDoc ''

     

       
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-
       
              If the `class` attribute is set and non-`null`, the module system will reject `imports` with a different `class`.

     

       
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-
       


     

       
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-
       
              This option contains the expected `class` attribute of the current module evaluation.

     

       
231
       
231
       
-
       
            '';

     

       
232
       
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-
       
          };

     

       
233
       
223
       
 
       
        };

     

       
234
       
224
       
 
       


     

       
235
       
225
       
 
       
        config = {

     
···

       
237
       
227
       
 
       
            inherit extendModules;

     

       
238
       
228
       
 
       
            moduleType = type;

     

       
239
       
229
       
 
       
          };

     

       
240
       
240
       
-
       
          _module.class = class;

     

       
241
       
230
       
 
       
          _module.specialArgs = specialArgs;

     

       
242
       
231
       
 
       
        };

     

       
243
       
232
       
 
       
      };

     
···

       
337
       
326
       
 
       
        config = checked (removeAttrs config [ "_module" ]);

     

       
338
       
327
       
 
       
        _module = checked (config._module);

     

       
339
       
328
       
 
       
        inherit extendModules type;

     

       
329
       
329
       
+
       
        configurationClass = class;

     

       
340
       
330
       
 
       
      };

     

       
341
       
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    in result;

     

       
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332
       
 
       


     

···

       
364
       
364
       
 
       


     

       
365
       
365
       
 
       
# Class checks, evalModules

     

       
366
       
366
       
 
       
checkConfigOutput '^{ }$' config.ok.config ./class-check.nix

     

       
367
       
367
       
+
       
checkConfigOutput '"nixos"' config.ok.configurationClass ./class-check.nix

     

       
367
       
368
       
 
       
checkConfigError 'The module .*/module-class-is-darwin.nix was imported into nixos instead of darwin.' config.fail.config ./class-check.nix

     

       
368
       
369
       
 
       
checkConfigError 'The module foo.nix#darwinModules.default was imported into nixos instead of darwin.' config.fail-anon.config ./class-check.nix

     

       
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370