webpack.SourceMapDevToolPlugin.append error -- "append can't be false when no filename is provided" ?

[pgnd]

with

yarn -v
	4.4.1
node -v
	v20.16.0
npm -v
	10.8.1

yarn info --name-only webpack
└─ webpack@npm:5.94.0

in my wp5 config, i set

const isProduction = process.env.NODE_ENV === 'production';
mode: isProduction ? 'production' : 'development',
...
devtool: false,

and, instead, use

new webpack.SourceMapDevToolPlugin({

	filename: isProduction ? false : 'sourcemaps/[name].[contenthash:8][ext].map',
	append: isProduction ? false : '\n//# sourceMappingURL=[url]',
	columns: true,
	module: true,
	moduleFilenameTemplate: undefined,
	fallbackModuleFilenameTemplate: undefined,
	noSources: true,
}),

, intended to generate only dev mode sourcemaps.

development mode build generates sourcemaps as intended.

production mode build returns

/srv/web/app/themes/theme01/.yarn/__virtual__/webpack-virtual-b4d35fb347/10/var/lib/wwwrun/.yarn/berry/cache/webpack-npm-5.94.0-d1e43de389-10c0.zip/node_modules/webpack/lib/SourceMapDevToolPlugin.js:551
                                                                                        throw new Error(
                                                                                              ^

Error: SourceMapDevToolPlugin: append can't be false when no filename is provided
    at /srv/web/app/themes/theme01/.yarn/__virtual__/webpack-virtual-b4d35fb347/10/var/lib/wwwrun/.yarn/berry/cache/webpack-npm-5.94.0-d1e43de389-10c0.zip/node_modules/webpack/lib/SourceMapDevToolPlugin.js:551:18
    at arrayEach (/var/lib/wwwrun/.yarn/berry/cache/neo-async-npm-2.6.2-75d6902586-10c0.zip/node_modules/neo-async/async.js:2405:9)
    at Object.each (/var/lib/wwwrun/.yarn/berry/cache/neo-async-npm-2.6.2-75d6902586-10c0.zip/node_modules/neo-async/async.js:2846:9)
    at /srv/web/app/themes/theme01/.yarn/__virtual__/webpack-virtual-b4d35fb347/10/var/lib/wwwrun/.yarn/berry/cache/webpack-npm-5.94.0-d1e43de389-10c0.zip/node_modules/webpack/lib/SourceMapDevToolPlugin.js:419:17
    at /var/lib/wwwrun/.yarn/berry/cache/neo-async-npm-2.6.2-75d6902586-10c0.zip/node_modules/neo-async/async.js:2830:7
    at done (/var/lib/wwwrun/.yarn/berry/cache/neo-async-npm-2.6.2-75d6902586-10c0.zip/node_modules/neo-async/async.js:2865:11)
    at /var/lib/wwwrun/.yarn/berry/cache/neo-async-npm-2.6.2-75d6902586-10c0.zip/node_modules/neo-async/async.js:2818:7
    at /srv/web/app/themes/theme01/.yarn/__virtual__/webpack-virtual-b4d35fb347/10/var/lib/wwwrun/.yarn/berry/cache/webpack-npm-5.94.0-d1e43de389-10c0.zip/node_modules/webpack/lib/SourceMapDevToolPlugin.js:350:9
    at /srv/web/app/themes/theme01/.yarn/__virtual__/webpack-virtual-b4d35fb347/10/var/lib/wwwrun/.yarn/berry/cache/webpack-npm-5.94.0-d1e43de389-10c0.zip/node_modules/webpack/lib/Cache.js:97:5
    at Hook.eval [as callAsync] (eval at create (/var/lib/wwwrun/.yarn/berry/cache/tapable-npm-2.2.1-8cf5ff3039-10c0.zip/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:6:1)

Node.js v20.16.0

unclear if this is a config issue, or a bug.

how to

(1) only generate sourcemap in dev mode,

AND

(2) append only in dev mode

?

[alexander-akait]

Can you create reproducible test repo, also you can use just empty string