fix(matchConfidence): align supported datasources list with internal preset

docs/usage/merge-confidence.md

@@ -29,6 +29,7 @@ Renovate will show Merge Confidence badges for these languages:
 
 | Language   | Datasource  |
 | ---------- | ----------- |
+| Golang     | `go`        |
 | JavaScript | `npm`       |
 | Java       | `maven`     |
 | Python     | `pypi`      |

docs/usage/self-hosted-experimental.md

@@ -126,6 +126,11 @@ Skip initializing `RE2` for regular expressions and instead use Node-native `Reg
 If set, Renovate will query this API for Merge Confidence data.
 This feature is in private beta.
 
+## `RENOVATE_X_MERGE_CONFIDENCE_SUPPORTED_DATASOURCES`
+
+If set, Renovate will query the merge-confidence JSON API only for datasources that are part of this list.
+The expected value for this environment variable is a JSON array of strings.
+
 ## `RENOVATE_X_PLATFORM_VERSION`
 
 If set, Renovate will use this string as GitLab server version instead of checking via the GitLab API.

lib/config/presets/internal/merge-confidence.ts

@@ -1,19 +1,21 @@
 import type { Preset } from '../types';
 
+export const supportedDatasources = [
+  'go',
+  'maven',
+  'npm',
+  'nuget',
+  'packagist',
+  'pypi',
+  'rubygems',
+];
+
 export const presets: Record<string, Preset> = {
   'all-badges': {
     description: 'Show all Merge Confidence badges for pull requests.',
     packageRules: [
       {
-        matchDatasources: [
-          'maven',
-          'npm',
-          'nuget',
-          'packagist',
-          'pypi',
-          'rubygems',
-          'go',
-        ],
+        matchDatasources: supportedDatasources,
         matchUpdateTypes: ['patch', 'minor', 'major'],
         prBodyColumns: [
           'Package',
@@ -31,15 +33,7 @@ export const presets: Record<string, Preset> = {
       'Show only the Age and Confidence Merge Confidence badges for pull requests.',
     packageRules: [
       {
-        matchDatasources: [
-          'maven',
-          'npm',
-          'nuget',
-          'packagist',
-          'pypi',
-          'rubygems',
-          'go',
-        ],
+        matchDatasources: supportedDatasources,
         matchUpdateTypes: ['patch', 'minor', 'major'],
         prBodyColumns: ['Package', 'Change', 'Age', 'Confidence'],
       },

lib/util/merge-confidence/index.spec.ts

@@ -9,6 +9,7 @@ import {
   initConfig,
   initMergeConfidence,
   isActiveConfidenceLevel,
+  parseSupportedDatasourceString,
   resetConfig,
   satisfiesConfidenceLevel,
 } from '.';
@@ -296,8 +297,11 @@ describe('util/merge-confidence/index', () => {
     });
 
     describe('initMergeConfidence()', () => {
-      it('using default base url if none is set', async () => {
+      beforeEach(() => {
         resetConfig();
+      });
+
+      it('using default base url if none is set', async () => {
         delete process.env.RENOVATE_X_MERGE_CONFIDENCE_API_BASE_URL;
         httpMock
           .scope(defaultApiBaseUrl)
@@ -309,12 +313,22 @@ describe('util/merge-confidence/index', () => {
           'using default merge confidence API base URL',
         );
         expect(logger.debug).toHaveBeenCalledWith(
+          {
+            supportedDatasources: [
+              'go',
+              'maven',
+              'npm',
+              'nuget',
+              'packagist',
+              'pypi',
+              'rubygems',
+            ],
+          },
           'merge confidence API - successfully authenticated',
         );
       });
 
       it('warns and then resolves if base url is invalid', async () => {
-        resetConfig();
         process.env.RENOVATE_X_MERGE_CONFIDENCE_API_BASE_URL =
           'invalid-url.com';
         httpMock
@@ -328,12 +342,12 @@ describe('util/merge-confidence/index', () => {
           'invalid merge confidence API base URL found in environment variables - using default value instead',
         );
         expect(logger.debug).toHaveBeenCalledWith(
+          expect.anything(),
           'merge confidence API - successfully authenticated',
         );
       });
 
       it('resolves if no token', async () => {
-        resetConfig();
         hostRules.clear();
 
         await expect(initMergeConfidence()).toResolve();
@@ -347,6 +361,7 @@ describe('util/merge-confidence/index', () => {
 
         await expect(initMergeConfidence()).toResolve();
         expect(logger.debug).toHaveBeenCalledWith(
+          expect.anything(),
           'merge confidence API - successfully authenticated',
         );
       });
@@ -389,6 +404,57 @@ describe('util/merge-confidence/index', () => {
           'merge confidence API request failed - aborting run',
         );
       });
+
+      describe('parseSupportedDatasourceList()', () => {
+        type ParseSupportedDatasourceTestCase = {
+          name: string;
+          datasourceListString: string | undefined;
+          expected: string[] | undefined;
+        };
+
+        afterEach(() => {
+          delete process.env.RENOVATE_X_MERGE_CONFIDENCE_SUPPORTED_DATASOURCES;
+        });
+
+        it.each([
+          {
+            name: 'it should do nothing when the input is undefined',
+            datasourceListString: undefined,
+            expected: undefined,
+          },
+          {
+            name: 'it should successfully parse the given datasource list',
+            datasourceListString: `["go","npm"]`,
+            expected: ['go', 'npm'],
+          },
+          {
+            name: 'it should gracefully handle invalid json',
+            datasourceListString: `{`,
+            expected: undefined,
+          },
+          {
+            name: 'it should discard non-array JSON input',
+            datasourceListString: `{}`,
+            expected: undefined,
+          },
+          {
+            name: 'it should discard non-string array JSON input',
+            datasourceListString: `[1,2]`,
+            expected: undefined,
+          },
+        ])(
+          `$name`,
+          ({
+            datasourceListString,
+            expected,
+          }: ParseSupportedDatasourceTestCase) => {
+            process.env.RENOVATE_X_MERGE_CONFIDENCE_SUPPORTED_DATASOURCES =
+              datasourceListString;
+
+            expect(parseSupportedDatasourceString()).toStrictEqual(expected);
+          },
+        );
+      });
     });
   });
 });

lib/util/merge-confidence/index.ts

@@ -1,8 +1,10 @@
 import is from '@sindresorhus/is';
+import { supportedDatasources as presetSupportedDatasources } from '../../config/presets/internal/merge-confidence';
 import type { UpdateType } from '../../config/types';
 import { logger } from '../../logger';
 import { ExternalHostError } from '../../types/errors/external-host-error';
 import * as packageCache from '../cache/package';
+import { parseJson } from '../common';
 import * as hostRules from '../host-rules';
 import { Http } from '../http';
 import { MERGE_CONFIDENCE } from './common';
@@ -12,8 +14,7 @@ const hostType = 'merge-confidence';
 const http = new Http(hostType);
 let token: string | undefined;
 let apiBaseUrl: string | undefined;
-
-const supportedDatasources = ['npm', 'maven', 'pypi'];
+let supportedDatasources: string[] = [];
 
 export const confidenceLevels: Record<MergeConfidence, number> = {
   low: -1,
@@ -25,14 +26,47 @@ export const confidenceLevels: Record<MergeConfidence, number> = {
 export function initConfig(): void {
   apiBaseUrl = getApiBaseUrl();
   token = getApiToken();
+  supportedDatasources =
+    parseSupportedDatasourceString() ?? presetSupportedDatasources;
+
   if (!is.nullOrUndefined(token)) {
     logger.debug(`Merge confidence token found for ${apiBaseUrl}`);
   }
 }
 
+export function parseSupportedDatasourceString(): string[] | undefined {
+  const supportedDatasourceString =
+    process.env.RENOVATE_X_MERGE_CONFIDENCE_SUPPORTED_DATASOURCES;
+
+  if (!is.string(supportedDatasourceString)) {
+    return undefined;
+  }
+
+  let parsedDatasourceList: unknown;
+  try {
+    parsedDatasourceList = parseJson(supportedDatasourceString, '.json5');
+  } catch (err) {
+    logger.error(
+      { supportedDatasourceString, err },
+      'Failed to parse supported datasources list; Invalid JSON format',
+    );
+  }
+
+  if (!is.array<string>(parsedDatasourceList, is.string)) {
+    logger.warn(
+      { parsedDatasourceList },
+      `Expected a string array but got ${typeof parsedDatasourceList}`,
+    );
+    return undefined;
+  }
+
+  return parsedDatasourceList;
+}
+
 export function resetConfig(): void {
   token = undefined;
   apiBaseUrl = undefined;
+  supportedDatasources = [];
 }
 
 export function isMergeConfidence(value: string): value is MergeConfidence {
@@ -190,7 +224,10 @@ export async function initMergeConfidence(): Promise<void> {
     apiErrorHandler(err);
   }
 
-  logger.debug('merge confidence API - successfully authenticated');
+  logger.debug(
+    { supportedDatasources },
+    'merge confidence API - successfully authenticated',
+  );
   return;
 }