fix(install-targets): validate compiled OpenCode plugin before install (#2041)

Fail fast when the OpenCode home install is attempted from a source checkout without the compiled .opencode/dist payload. PR had the full CI matrix green.

scripts/lib/install-targets/opencode-home.js

@@ -1,4 +1,83 @@
-const { createInstallTargetAdapter } = require('./helpers');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+
+const {
+  buildValidationIssue,
+  createInstallTargetAdapter,
+} = require('./helpers');
+
+const COMPILED_PLUGIN_DIST_DIR = path.join('.opencode', 'dist');
+const REQUIRED_COMPILED_ARTEFACTS = Object.freeze([
+  { relativePath: path.join(COMPILED_PLUGIN_DIST_DIR, 'index.js'), expectedType: 'file' },
+  { relativePath: path.join(COMPILED_PLUGIN_DIST_DIR, 'plugins'), expectedType: 'directory' },
+  { relativePath: path.join(COMPILED_PLUGIN_DIST_DIR, 'tools'), expectedType: 'directory' },
+]);
+const BUILD_COMMAND_HINT = 'node scripts/build-opencode.js (or: npm run build:opencode)';
+
+// Errors that mean "this artefact does not exist at the expected path / type".
+// Anything else (EACCES, EIO, ...) is a genuine system fault we surface to the
+// caller rather than masking as a missing artefact.
+const MISSING_ARTEFACT_ERROR_CODES = new Set(['ENOENT', 'ENOTDIR']);
+
+function isExpectedType(absolutePath, expectedType) {
+  let stat;
+  try {
+    stat = fs.statSync(absolutePath);
+  } catch (error) {
+    if (error && MISSING_ARTEFACT_ERROR_CODES.has(error.code)) {
+      return false;
+    }
+    throw error;
+  }
+  return expectedType === 'file' ? stat.isFile() : stat.isDirectory();
+}
+
+function defaultValidateOpencodeHome(input = {}) {
+  if (!input.homeDir && !os.homedir()) {
+    return [
+      buildValidationIssue(
+        'error',
+        'missing-home-dir',
+        'homeDir is required for home install targets'
+      ),
+    ];
+  }
+
+  if (!input.repoRoot) {
+    return [];
+  }
+
+  const missingPaths = REQUIRED_COMPILED_ARTEFACTS
+    .map(artefact => ({
+      relativePath: artefact.relativePath,
+      absolutePath: path.join(input.repoRoot, artefact.relativePath),
+      expectedType: artefact.expectedType,
+    }))
+    .filter(entry => !isExpectedType(entry.absolutePath, entry.expectedType));
+
+  if (missingPaths.length > 0) {
+    const missingList = missingPaths.map(entry => entry.relativePath).join(', ');
+    return [
+      buildValidationIssue(
+        'error',
+        'opencode-plugin-not-built',
+        'OpenCode install requires the compiled plugin payload under '
+          + `${COMPILED_PLUGIN_DIST_DIR}, but the following artefact(s) were `
+          + `missing or had the wrong type: ${missingList}. Run `
+          + `${BUILD_COMMAND_HINT} from the repo root before re-running the `
+          + 'installer.',
+        {
+          missingPaths: missingPaths.map(entry => entry.absolutePath),
+          missingRelativePaths: missingPaths.map(entry => entry.relativePath),
+          expectedTypes: missingPaths.map(entry => entry.expectedType),
+        }
+      ),
+    ];
+  }
+
+  return [];
+}
 
 module.exports = createInstallTargetAdapter({
   id: 'opencode-home',
@@ -7,4 +86,5 @@ module.exports = createInstallTargetAdapter({
   rootSegments: ['.opencode'],
   installStatePathSegments: ['ecc-install-state.json'],
   nativeRootRelativePath: '.opencode',
+  validate: defaultValidateOpencodeHome,
 });