more strict error type checking in most packages and backend plugins

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/config-loader/package.json

@@ -32,6 +32,7 @@
   "dependencies": {
     "@backstage/cli-common": "^0.1.4",
     "@backstage/config": "^0.1.9",
+    "@backstage/errors": "^0.1.2",
     "@types/json-schema": "^7.0.6",
     "ajv": "^7.0.3",
     "chokidar": "^3.5.2",

packages/config-loader/src/lib/env.ts

@@ -15,6 +15,7 @@
  */
 
 import { AppConfig, JsonObject } from '@backstage/config';
+import { assertError } from '@backstage/errors';
 
 const ENV_PREFIX = 'APP_CONFIG_';
 
@@ -96,6 +97,7 @@ function safeJsonParse(str: string): [Error | null, any] {
   try {
     return [null, JSON.parse(str)];
   } catch (err) {
+    assertError(err);
     return [err, str];
   }
 }

packages/config-loader/src/lib/schema/collect.ts

@@ -24,6 +24,7 @@ import {
 import { ConfigSchemaPackageEntry } from './types';
 import { getProgramFromFiles, generateSchema } from 'typescript-json-schema';
 import { JsonObject } from '@backstage/config';
+import { assertError } from '@backstage/errors';
 
 type Item = {
   name?: string;
@@ -189,6 +190,7 @@ function compileTsSchemas(paths: string[]) {
         [path.split(sep).join('/')], // Unix paths are expected for all OSes here
       ) as JsonObject | null;
     } catch (error) {
+      assertError(error);
       if (error.message !== 'type Config not found') {
         throw error;
       }

packages/config-loader/src/lib/transform/apply.ts

@@ -15,6 +15,7 @@
  */
 
 import { JsonObject, JsonValue } from '@backstage/config';
+import { assertError } from '@backstage/errors';
 import { TransformFunc } from './types';
 import { isObject } from './utils';
 
@@ -46,6 +47,7 @@ export async function applyConfigTransforms(
           break;
         }
       } catch (error) {
+        assertError(error);
         throw new Error(`error at ${path}, ${error.message}`);
       }
     }

packages/config-loader/src/loader.ts

@@ -19,6 +19,7 @@ import yaml from 'yaml';
 import chokidar from 'chokidar';
 import { resolve as resolvePath, dirname, isAbsolute, basename } from 'path';
 import { AppConfig } from '@backstage/config';
+import { ForwardedError } from '@backstage/errors';
 import {
   applyConfigTransforms,
   readEnvConfig,
@@ -114,9 +115,7 @@ export async function loadConfig(
   try {
     fileConfigs = await loadConfigFiles();
   } catch (error) {
-    throw new Error(
-      `Failed to read static configuration file, ${error.message}`,
-    );
+    throw new ForwardedError('Failed to read static configuration file', error);
   }
 
   const envConfigs = await readEnvConfig(process.env);