feat(run): Show a "no bin scripts" or "no scripts available" message (#4891)

**Summary**

This adds the additional warning if there are no bin scripts or if there are no scripts available. If no scripts are available, scripts will not be listed.

I created this pull request when running `yarn run` without any scripts specified, yarn would try to ask the user to specify which script.

To view this feature in the CLI, run `yarn run` inside a project without any bin or scripts available.
For example:
```bash
$ yarn run
yarn run v1.3.2
error No command specified.
error There are no binary scripts available.
error There are no scripts specified inside package.json.
Done in 0.13s.
```

**Test plan**

This new functionality is tested with the `returns noScriptsAvailable and noBinAvailable with no bins and scripts` test.

This test checks if the implemented error messages are thrown.

Author: maxchehab

__tests__/commands/__snapshots__/run.js.snap

@@ -0,0 +1,63 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`returns noBinAvailable with no bins 1`] = `
+Array [
+  Object {
+    "data": "No command specified.",
+    "error": true,
+    "type": "error",
+  },
+  Object {
+    "data": "There are no binary scripts available.",
+    "error": true,
+    "type": "error",
+  },
+  Object {
+    "data": "Project commands",
+    "error": false,
+    "type": "info",
+  },
+  Object {
+    "data": Object {
+      "hints": Object {
+        "build": "echo 'building'",
+        "prestart": "echo 'prestart'",
+        "start": "node index.js",
+      },
+      "items": Array [
+        "build",
+        "prestart",
+        "start",
+      ],
+      "type": "possibleCommands",
+    },
+    "error": false,
+    "type": "list",
+  },
+  Object {
+    "data": "No command specified.",
+    "error": true,
+    "type": "error",
+  },
+]
+`;
+
+exports[`returns noScriptsAvailable with no scripts 1`] = `
+Array [
+  Object {
+    "data": "No command specified.",
+    "error": true,
+    "type": "error",
+  },
+  Object {
+    "data": "Commands available from binary scripts: cat-names",
+    "error": false,
+    "type": "info",
+  },
+  Object {
+    "data": "There are no scripts specified inside package.json.",
+    "error": true,
+    "type": "error",
+  },
+]
+`;

__tests__/commands/run.js

@@ -145,6 +145,18 @@ test('adds quotes if args have spaces and quotes', (): Promise<void> => {
   });
 });
 
+test('returns noScriptsAvailable with no scripts', (): Promise<void> => {
+  return runRun([], {}, 'no-scripts', (config, reporter) => {
+    expect(reporter.getBuffer()).toMatchSnapshot();
+  });
+});
+
+test('returns noBinAvailable with no bins', (): Promise<void> => {
+  return runRun([], {}, 'no-bin', (config, reporter) => {
+    expect(reporter.getBuffer()).toMatchSnapshot();
+  });
+});
+
 test('adds workspace root node_modules/.bin to path when in a workspace', (): Promise<void> => {
   return runRunInWorkspacePackage('packages/pkg1', ['env'], {}, 'workspace', (config, reporter): ?Promise<void> => {
     const logEntry = reporter.getBuffer().find(entry => entry.type === 'log');

__tests__/fixtures/run/no-bin/package.json

@@ -0,0 +1,8 @@
+{
+  "license": "MIT",
+  "scripts": {
+    "build": "echo 'building'",
+    "start": "node index.js",
+    "prestart": "echo 'prestart'"
+  }
+}

__tests__/fixtures/run/no-scripts/node_modules/.bin/cat-names

@@ -0,0 +1,3 @@
+{
+    "license": "MIT"
+}

__tests__/fixtures/run/no-scripts/package.json

@@ -104,12 +104,22 @@ export async function run(config: Config, reporter: Reporter, flags: Object, arg
   // list possible scripts if none specified
   if (args.length === 0) {
     reporter.error(reporter.lang('commandNotSpecified'));
-    reporter.info(`${reporter.lang('binCommands') + binCommands.join(', ')}`);
-    reporter.info(`${reporter.lang('possibleCommands')}`);
-    reporter.list('possibleCommands', pkgCommands, cmdHints);
-    await reporter
-      .question(reporter.lang('commandQuestion'))
-      .then(answer => runCommand(answer.split(' ')), () => reporter.error(reporter.lang('commandNotSpecified')));
+
+    if (binCommands.length) {
+      reporter.info(`${reporter.lang('binCommands') + binCommands.join(', ')}`);
+    } else {
+      reporter.error(reporter.lang('noBinAvailable'));
+    }
+
+    if (pkgCommands.length) {
+      reporter.info(`${reporter.lang('possibleCommands')}`);
+      reporter.list('possibleCommands', pkgCommands, cmdHints);
+      await reporter
+        .question(reporter.lang('commandQuestion'))
+        .then(answer => runCommand(answer.split(' ')), () => reporter.error(reporter.lang('commandNotSpecified')));
+    } else {
+      reporter.error(reporter.lang('noScriptsAvailable'));
+    }
     return Promise.resolve();
   } else {
     return runCommand(args);

src/cli/commands/run.js

@@ -199,6 +199,8 @@ const messages = {
 
   execMissingCommand: 'Missing command name.',
 
+  noScriptsAvailable: 'There are no scripts specified inside package.json.',
+  noBinAvailable: 'There are no binary scripts available.',
   dashDashDeprecation: `From Yarn 1.0 onwards, scripts don't require "--" for options to be forwarded. In a future version, any explicit "--" will be forwarded as-is to the scripts.`,
   commandNotSpecified: 'No command specified.',
   binCommands: 'Commands available from binary scripts: ',