From 35a3bd2d2e000f4dc3339261c43207a8e9e0b58f Mon Sep 17 00:00:00 2001
From: Josh Goldberg <josh@codecademy.com>
Date: Tue, 7 Jul 2020 17:07:14 -0400
Subject: [PATCH] Fix: Added more specific notice for invalid (:) plugin names

---
 lib/cli-engine/config-array-factory.js       |  4 ++--
 lib/shared/naming.js                         |  2 +-
 messages/plugin-invalid.txt                  |  9 +++++++++
 tests/lib/cli-engine/config-array-factory.js | 18 ++++++++++++++++++
 tests/lib/shared/naming.js                   |  3 ++-
 5 files changed, 32 insertions(+), 4 deletions(-)
 create mode 100644 messages/plugin-invalid.txt

diff --git a/lib/cli-engine/config-array-factory.js b/lib/cli-engine/config-array-factory.js
index 7c0fba65c67..06357d0197d 100644
--- a/lib/cli-engine/config-array-factory.js
+++ b/lib/cli-engine/config-array-factory.js
@@ -802,7 +802,7 @@ class ConfigArrayFactory {
      */
     _loadExtendedPluginConfig(extendName, ctx) {
         const slashIndex = extendName.lastIndexOf("/");
-        const pluginName = extendName.slice("plugin:".length, slashIndex);
+        const pluginName = slashIndex === -1 ? extendName : extendName.slice("plugin:".length, slashIndex);
         const configName = extendName.slice(slashIndex + 1);
 
         if (isFilePath(pluginName)) {
@@ -994,7 +994,7 @@ class ConfigArrayFactory {
             error = resolveError;
             /* istanbul ignore else */
             if (error && error.code === "MODULE_NOT_FOUND") {
-                error.messageTemplate = "plugin-missing";
+                error.messageTemplate = request.indexOf(":") === -1 ? "plugin-missing" : "plugin-invalid";
                 error.messageData = {
                     pluginName: request,
                     resolvePluginsRelativeTo: ctx.pluginBasePath,
diff --git a/lib/shared/naming.js b/lib/shared/naming.js
index 32cff94538a..e959a18c035 100644
--- a/lib/shared/naming.js
+++ b/lib/shared/naming.js
@@ -43,7 +43,7 @@ function normalizePackageName(name, prefix) {
              */
             normalizedName = normalizedName.replace(/^@([^/]+)\/(.*)$/u, `@$1/${prefix}-$2`);
         }
-    } else if (!normalizedName.startsWith(`${prefix}-`)) {
+    } else if (!normalizedName.startsWith(`${prefix}-`) && normalizedName.indexOf(":") === -1) {
         normalizedName = `${prefix}-${normalizedName}`;
     }
 
diff --git a/messages/plugin-invalid.txt b/messages/plugin-invalid.txt
new file mode 100644
index 00000000000..6d6e39d80b0
--- /dev/null
+++ b/messages/plugin-invalid.txt
@@ -0,0 +1,9 @@
+ESLint couldn't find the plugin "<%- pluginName %>".
+
+(The package "<%- pluginName %>" was not found when loaded as a Node module from the directory "<%- resolvePluginsRelativeTo %>".)
+
+It looks like this might not be a valid plugin name. Did you use the name of a preset configuration instead of a plugin?
+
+The plugin "<%- pluginName %>" was referenced from the config file in "<%- importerName %>".
+
+If you still can't figure out the problem, please stop by https://eslint.org/chat to chat with the team.
diff --git a/tests/lib/cli-engine/config-array-factory.js b/tests/lib/cli-engine/config-array-factory.js
index 3b979c1d38f..90c80e3672f 100644
--- a/tests/lib/cli-engine/config-array-factory.js
+++ b/tests/lib/cli-engine/config-array-factory.js
@@ -1503,6 +1503,24 @@ describe("ConfigArrayFactory", () => {
             }, /Failed to load config "plugin:invalid-config\/bar" to extend from./u);
         });
 
+        it("should throw an error with a message template when a plugin referenced for a plugin config is invalid", () => {
+            try {
+                applyExtends({
+                    extends: "plugin:nonexistent-plugin",
+                    rules: { eqeqeq: 2 }
+                });
+            } catch (err) {
+                assert.strictEqual(err.messageTemplate, "plugin-invalid");
+                assert.deepStrictEqual(err.messageData, {
+                    pluginName: "plugin:nonexistent-plugin",
+                    resolvePluginsRelativeTo: process.cwd(),
+                    importerName: "whatever"
+                });
+                return;
+            }
+            assert.fail("Expected to throw an error");
+        });
+
         it("should throw an error with a message template when a plugin referenced for a plugin config is not found", () => {
             try {
                 applyExtends({
diff --git a/tests/lib/shared/naming.js b/tests/lib/shared/naming.js
index 0a868a872ed..8e6fdb99d85 100644
--- a/tests/lib/shared/naming.js
+++ b/tests/lib/shared/naming.js
@@ -25,7 +25,8 @@ describe("naming", () => {
             ["@z\\foo", "@z/eslint-config-foo"],
             ["@z\\foo\\bar.js", "@z/eslint-config-foo/bar.js"],
             ["@z/eslint-config", "@z/eslint-config"],
-            ["@z/eslint-config-foo", "@z/eslint-config-foo"]
+            ["@z/eslint-config-foo", "@z/eslint-config-foo"],
+            ["plugin:invalid", "plugin:invalid"]
         ], (input, expected) => {
             it(`should return ${expected} when passed ${input}`, () => {
                 const result = naming.normalizePackageName(input, "eslint-config");