Fix: improve diagnostics for shareable-config-missing errors

lib/cli-engine/config-array-factory.js

@@ -224,15 +224,16 @@ function loadPackageJSONConfigFile(filePath) {
 /**
  * Creates an error to notify about a missing config to extend from.
  * @param {string} configName The name of the missing config.
+ * @param {string} importerName The name of the config that imported the missing config
  * @returns {Error} The error object to throw
  * @private
  */
-function configMissingError(configName) {
+function configMissingError(configName, importerName) {
     return Object.assign(
         new Error(`Failed to load config "${configName}" to extend from.`),
         {
             messageTemplate: "extend-config-missing",
-            messageData: { configName }
+            messageData: { configName, importerName }
         }
     );
 }
@@ -637,7 +638,7 @@ class ConfigArrayFactory {
             return this._loadConfigData(eslintAllPath, name);
         }
 
-        throw configMissingError(extendName);
+        throw configMissingError(extendName, importerName);
     }
 
     /**
@@ -670,7 +671,7 @@ class ConfigArrayFactory {
             );
         }
 
-        throw plugin.error || configMissingError(extendName);
+        throw plugin.error || configMissingError(extendName, importerPath);
     }
 
     /**
@@ -704,7 +705,7 @@ class ConfigArrayFactory {
         } catch (error) {
             /* istanbul ignore else */
             if (error && error.code === "MODULE_NOT_FOUND") {
-                throw configMissingError(extendName);
+                throw configMissingError(extendName, importerPath);
             }
             throw error;
         }

messages/extend-config-missing.txt

@@ -1,3 +1,5 @@
 ESLint couldn't find the config "<%- configName %>" to extend from. Please check that the name of the config is correct.
 
+The config "<%- configName %>" was referenced from the config file in "<%- importerName %>".
+
 If you still have problems, please stop by https://gitter.im/eslint/eslint to chat with the team.

tests/lib/cli-engine/cli-engine.js

@@ -3338,7 +3338,8 @@ describe("CLIEngine", () => {
                 } catch (err) {
                     assert.strictEqual(err.messageTemplate, "extend-config-missing");
                     assert.deepStrictEqual(err.messageData, {
-                        configName: "nonexistent-config"
+                        configName: "nonexistent-config",
+                        importerName: getFixturePath("module-not-found", "extends-js", ".eslintrc.yml")
                     });
                     return;
                 }