Don't cache default plugin builds from a modified source checkout

Untracked or modified files in plugin-sources are included in the build but not in the cache key.

.github/workflows/shared/setup-build-environment/action.yml

@@ -76,3 +76,10 @@ runs:
     - uses: actions/setup-python@v6
       with:
         python-version: '3.14'
+
+    # Building the default plugins from source takes several minutes on Windows. Must be restored
+    # before "yarn install", which builds them.
+    - uses: actions/cache@v6
+      with:
+        path: packages/default-plugins/build-cache
+        key: default-plugins-${{ runner.os }}-${{ hashFiles('packages/default-plugins/pluginRepositories.json', 'packages/default-plugins/plugin-patches/**', 'packages/default-plugins/buildDefaultPlugins.ts') }}

packages/default-plugins/.gitignore

@@ -1,2 +1,3 @@
 built-plugins/
-plugin-sources/*
+plugin-sources/*
+build-cache/

packages/default-plugins/buildDefaultPlugins.ts

@@ -1,9 +1,10 @@
 
 /* eslint-disable no-console */
 
-import { copy, exists, remove, readdir, mkdtemp } from 'fs-extra';
+import { copy, exists, remove, readdir, mkdtemp, readFile } from 'fs-extra';
 import { join, resolve, basename } from 'path';
 import { tmpdir } from 'os';
+import { createHash } from 'crypto';
 import { chdir, cwd } from 'process';
 import { execCommand } from '@joplin/utils';
 import { glob } from 'glob';
@@ -16,8 +17,22 @@ interface Options {
 	outputParentDir: string|null;
 	beforeInstall: (buildDir: string, pluginName: string)=> Promise<void>;
 	beforePatch: ()=> Promise<void>;
+	useBuildCache: boolean;
 }
 
+// Increment to invalidate cached builds, for example after changing how plugins are built
+const buildCacheVersion = 1;
+const buildCacheDir = process.env.JOPLIN_DEFAULT_PLUGINS_CACHE_DIR || join(__dirname, 'build-cache');
+
+const getBuildCachePath = async (pluginId: string, repositoryData: RepositoryData) => {
+	const patchFile = getPathToPatchFileFor(pluginId);
+	const patch = await exists(patchFile) ? await readFile(patchFile, 'utf8') : '';
+	const hash = createHash('sha256')
+		.update(JSON.stringify([buildCacheVersion, pluginId, repositoryData.cloneUrl, repositoryData.commit, patch]))
+		.digest('hex');
+	return join(buildCacheDir, `${pluginId}-${hash.substring(0, 16)}.jpl`);
+};
+
 const buildDefaultPlugins = async (options: Options) => {
 	const pluginRepositoryData = await readRepositoryJson(join(__dirname, 'pluginRepositories.json'));
 
@@ -26,7 +41,23 @@ const buildDefaultPlugins = async (options: Options) => {
 		const outputPath = options.outputParentDir && join(options.outputParentDir, `${pluginId}.jpl`);
 
 		if (repositoryData.type === BuiltInPluginType.Built) {
-			await buildPlugin(pluginId, repositoryData, outputPath, options);
+			const cachePath = options.useBuildCache && outputPath ? await getBuildCachePath(pluginId, repositoryData) : null;
+			if (cachePath && await exists(cachePath)) {
+				logStatus('Using cached build of', pluginId, 'from', cachePath);
+				await copy(cachePath, outputPath);
+				continue;
+			}
+
+			const sourceHasLocalChanges = await buildPlugin(pluginId, repositoryData, outputPath, options);
+
+			if (cachePath) {
+				if (sourceHasLocalChanges) {
+					logStatus('Not caching build of', pluginId, ': its source checkout has local changes');
+				} else {
+					await copy(outputPath, cachePath);
+					logStatus('Saved build of', pluginId, 'to', cachePath);
+				}
+			}
 		} else {
 			if (!outputPath) {
 				console.warn('Skipping NPM plugin,', pluginId, ': missing output path.');
@@ -80,6 +111,9 @@ const buildPlugin = async (pluginId: string, repositoryData: RepositoryData, out
 			throw new Error(`Unable to checkout commit ${expectedCommitHash}`);
 		}
 
+		// Local changes are included in the build but not in the build cache key
+		const sourceHasLocalChanges = (await execCommand(['git', 'status', '--porcelain'], { showStdout: false })).trim() !== '';
+
 		logStatus('Copying repository files...');
 		await copy(pluginDir, buildDir, {
 			filter: fileName => {
@@ -122,6 +156,8 @@ const buildPlugin = async (pluginId: string, repositoryData: RepositoryData, out
 		} else {
 			console.warn('No output directory specified. Not copying built .jpl files.');
 		}
+
+		return sourceHasLocalChanges;
 	} catch (error) {
 		console.error(error);
 		console.log('Build directory', buildDir);

packages/default-plugins/commands/buildAll.ts

@@ -5,6 +5,7 @@ const buildAll = (outputDirectory: string) => {
 		outputParentDir: outputDirectory,
 		beforeInstall: async () => { },
 		beforePatch: async () => { },
+		useBuildCache: true,
 	});
 };
 

packages/default-plugins/commands/editPatch.ts

@@ -10,6 +10,7 @@ const editPatch = async (targetPluginId: string, outputParentDir: string|null) =
 
 	await buildDefaultPlugins({
 		outputParentDir: outputParentDir,
+		useBuildCache: false,
 		beforePatch: async () => {
 			// To make updating just the patch possible, a commit is created just before applying
 			// the patch.