Fix webpack build failure with gas-webpack-plugin

[Yuto-24]

Summary

npm run build fails during the webpack step after rimraf dist succeeds.

This was found while validating the js-yaml security advisory fix on branch fix/dependabot-js-yaml. The js-yaml fix itself is separate: npm ls js-yaml resolves to js-yaml@4.2.0, and npm test passes. This issue tracks the remaining webpack build failure as a separate follow-up.

Reproduction

npm run build

The build script is:

npm run lint && npm run test && rimraf dist && webpack && cpx src/appsscript.json dist && cpx "src/**/*.html" dist

Observed result

lint and test pass, then webpack fails:

(node:2540642) [DEP_WEBPACK_COMPILATION_OPTIMIZE_CHUNK_ASSETS] DeprecationWarning: optimizeChunkAssets is deprecated (use Compilation.hooks.processAssets instead and use one of Compilation.PROCESS_ASSETS_STAGE_* as stage option)
/home/yuto/github/Yuto-24/SlackLog/node_modules/webpack/lib/Compilation.js:5043
                        if (buildInfo.assets) {
                                      ^

TypeError: Cannot read properties of undefined (reading 'assets')
    at Compilation.createModuleAssets (/home/yuto/github/Yuto-24/SlackLog/node_modules/webpack/lib/Compilation.js:5043:18)
    at /home/yuto/github/Yuto-24/SlackLog/node_modules/webpack/lib/Compilation.js:3484:13
    at Compilation._runCodeGenerationJobs (/home/yuto/github/Yuto-24/SlackLog/node_modules/webpack/lib/Compilation.js:3639:11)
    at /home/yuto/github/Yuto-24/SlackLog/node_modules/webpack/lib/Compilation.js:3466:12
    at /home/yuto/github/Yuto-24/SlackLog/node_modules/webpack/lib/Compilation.js:3733:6
    at /home/yuto/github/Yuto-24/SlackLog/node_modules/neo-async/async.js:2818:7
    at done (/home/yuto/github/Yuto-24/SlackLog/node_modules/neo-async/async.js:3522:9)
    at /home/yuto/github/Yuto-24/SlackLog/node_modules/webpack/lib/Compilation.js:3694:8
    at /home/yuto/github/Yuto-24/SlackLog/node_modules/webpack/lib/Compilation.js:3813:5
    at /home/yuto/github/Yuto-24/SlackLog/node_modules/webpack/lib/Cache.js:98:34

Node.js v25.9.0

Current webpack-related setup

• webpack: 5.106.1
• webpack-cli: 4.10.0
• gas-webpack-plugin: 1.2.3
• webpack.config.js uses new GasPlugin()

Notes

Because the script removes dist/ before invoking webpack, a failed build leaves dist/appsscript.json and dist/slackLog.js as deleted files in the working tree. Those deleted dist/ changes should not be committed as part of unrelated dependency/security fixes.

Expected result

npm run build should complete successfully and regenerate dist/ artifacts.

Possible direction

Investigate compatibility between gas-webpack-plugin@1.2.3 and webpack 5. Options may include:

• updating or replacing gas-webpack-plugin
• adjusting the webpack plugin usage/configuration
• pinning webpack to a compatible version if the project expects the old plugin behavior

Keep this separate from the js-yaml security advisory fix so dependency security remediation and build pipeline repair remain reviewable independently.