Cannot override main entry template without also specifying the path to the entry again

[eliperelman]

With the Neutrino 9 beta, if you try overriding the template, you will get an exception:

module.exports = {
  options: {
    root: __dirname,
    mains: {
      index: {
        template: join(__dirname, "src/template.ejs"),
      },
    },
  },
  // ...
};

❯ yarn build
yarn run v1.10.1
$ webpack --mode production
/Users/eli/code/project/node_modules/webpack-cli/bin/cli.js:244
				throw err;
				^

TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received type undefined

If you re-specify the entry, it works as expected:

module.exports = {
  options: {
    root: __dirname,
    mains: {
      index: {
        entry: join(__dirname, "src/index.js"),
        template: join(__dirname, "src/template.ejs"),
      },
    },
  },
  // ...
};

[edmorley]

For a single entry-point project I would expect the html options to be set via html in the web preset options instead (since the mains options are meant as overrides). However I can see this still being an issue when eg multi-entrypoint and the first page wants a custom template but the others are using the global default via the html preset option.

[edmorley]

@eliperelman what's the expected behaviour here? A more user-friendly error saying "must specify source" or special-casing index and merging the source value in there too? The former would also help the case where someone lists additional mains that are missing their source, whereas the latter would only help for index.

[eliperelman]

My thought was the solution should be a merge of the existing value if its an object.

[edmorley]

Would you mind taking this one?

[edmorley]

@eliperelman do you know if you'll get a chance to look at this? :-)

[eliperelman]

I'll see if I can look at it soon.