Providing __system_context__ when an entry point sets library.type = 'system'

Bug report

What is the current behavior?

When setting library.type per entry point, __system_context__ is not set for SystemJS entry points and compilation sometimes fails.

If the current behavior is a bug, please provide the steps to reproduce.

The easiest way to reproduce this is by changing the test in configCases/target/system-context.

The original config:

/** @type {import("../../../../").Configuration} */
module.exports = {
    output: {
	library: {
	    type: "system"
	}
    },
    node: {
	__dirname: false,
	__filename: false
    }
};

I would expect the following config to behave the same:

/** @type {import("../../../../").Configuration} */
module.exports = {
    entry: {
        main: {
	    import: "./index.js",
	    library: {
		type: "system"
	    }
	}
    },
    node: {
	__dirname: false,
	__filename: false
    }
};

But it causes an error:

TypeError: Cannot read property 'type' of undefined

      219 | 				.for(RuntimeGlobals.systemContext)
      220 | 				.tap("RuntimePlugin", chunk => {
    > 221 | 					if (compilation.outputOptions.library.type === "system") {
          | 					                                      ^
      222 | 						compilation.addRuntimeModule(
      223 | 							chunk,
      224 | 							new SystemContextRuntimeModule()

      at lib/RuntimePlugin.js:221:44
      at Hook.eval (eval at create (node_modules/tapable/lib/HookCodeFactory.js:19:10), <anonymous>:13:16)
      at Hook.CALL_DELEGATE [as _call] (node_modules/tapable/lib/Hook.js:14:14)
      at Compilation.processRuntimeRequirements (lib/Compilation.js:2848:7)
      at lib/Compilation.js:2477:12
      at lib/Compilation.js:2680:5
      at node_modules/neo-async/async.js:2818:7
      at done (node_modules/neo-async/async.js:3522:9)
      at lib/Compilation.js:2660:7
      at lib/Compilation.js:2748:32

If there is another library.type set under output then the compilation is successful, but __system_context__ is undefined when running the application.

What is the expected behavior?

Compilation does not fail when output.library.type is not set. __system_context__ is available for entry points with library.type = 'system'.

Other relevant information: webpack version: 5.40.0 Node.js version: 14.17.0 Operating System: macOS 11.4 Additional tools:

[cjpearson]

It looks like the docs already mentioned that it’s deprecated. I think the test was written before that though.

[alexander-akait]

bump