fix: bump npm infrastructure dependencies and make sure changing serve.js content is applied

[simschla]

In #2462 we introduced the support for using the same node-modules-dir for multiple spotless steps requiring the same dependencies. To achieve this, the serve.js files were updated to accept a UUID when starting a npm-based server so that the java side knows which server-process (which port) it may use.

This created a problem we did not foresee: If a user has a running spotless installation before this change, then updates to the version containing this change, it leads to a problematic situation: the existing node-modules-dir (created by the previous spotless version and thus containing the old serve.js files without the UUID-change) would prevent the new spotless version from using the new serve.js files (containing the UUID-change) because the md5 hash used in the node-modules-dir's name did only respect the package.json content, not the serve.js content.

This PR changes this, so that the content of the package.json as well as the content of the serve.js files is respected in order to calculate a md5 hash for naming the node-modules-dir. So if any of these files change, a new node-modules-dir is used.

This PR also bumps the dependencies used behind the scenes for creating and managing the npm server process.

[Copilot]

Pull Request Overview

This PR ensures the serve.js content is included when hashing node-modules directories and bumps the underlying npm server dependencies.

• Extend MD5 hashing to cover both package.json and serve.js contents
• Update NodeServerLayout and step state to pass through serve script content
• Bump versions of Express and graceful-shutdown packages in all serve scripts

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
lib/src/test/java/com/diffplug/spotless/npm/NpmResourceHelperTest.java	Added unit tests for the new MD5 overload
lib/src/test/java/com/diffplug/spotless/npm/NodeServerLayoutTest.java	Added tests to verify the hash changes when serve.js differs
lib/src/main/resources/com/diffplug/spotless/npm/tsfmt-serve.js	Fixed typo when sending error messages
lib/src/main/resources/com/diffplug/spotless/npm/common-serve.js	Replaced old shutdown manager with http-graceful-shutdown
lib/src/main/resources/com/diffplug/spotless/npm/tsfmt-package.json	Bumped server package to v4.0.0 and updated dependencies
lib/src/main/resources/com/diffplug/spotless/npm/prettier-package.json	Bumped server package to v4.0.0 and updated dependencies
lib/src/main/resources/com/diffplug/spotless/npm/eslint-package.json	Bumped server package to v4.0.0 and updated dependencies
lib/src/main/java/com/diffplug/spotless/npm/NpmResourceHelper.java	Extended md5 to accept multiple contents and updated implementation
lib/src/main/java/com/diffplug/spotless/npm/NpmFormatterStepStateBase.java	Pass serve.js content into NodeServerLayout
lib/src/main/java/com/diffplug/spotless/npm/NodeServerLayout.java	Revised directory name generation to include serve script hash
lib/build.gradle	Added testlib project to testing classpath

Comments suppressed due to low confidence (5)

lib/src/main/java/com/diffplug/spotless/npm/NpmResourceHelper.java:146

• [nitpick] The variable name additionalFilecontentStream mixes casing and violates CamelCase conventions. Consider renaming it to additionalFileContentStream for consistency.

Stream<String> additionalFilecontentStream = Stream.concat( 

lib/src/main/resources/com/diffplug/spotless/npm/common-serve.js:3

• [nitpick] The imported function is assigned to a generic name. Consider renaming the shutdown handler (e.g., to shutdownServer) to avoid confusion with system-level shutdown methods.

const gracefulShutdown = require("http-graceful-shutdown"); 

lib/src/main/resources/com/diffplug/spotless/npm/tsfmt-package.json:12

• Runtime dependencies like express and http-graceful-shutdown are declared under devDependencies. If these scripts run in production, consider moving them to dependencies to ensure they're always installed.

"express": "5.1.0", 

lib/src/main/resources/com/diffplug/spotless/npm/prettier-package.json:12

• Runtime dependencies like express and http-graceful-shutdown are declared under devDependencies. If these scripts run in production, consider moving them to dependencies to ensure they're always installed.

"express": "5.1.0", 

lib/src/main/resources/com/diffplug/spotless/npm/eslint-package.json:12

• Runtime dependencies like express and http-graceful-shutdown are declared under devDependencies. If these scripts run in production, consider moving them to dependencies to ensure they're always installed.

"express": "5.1.0", 

[nedtwigg]

Released in plugin-gradle 7.1.0 and plugin-maven 2.45.0.