fix(@angular/cli): keep schematic positional arguments in index order

sort checked `positional` for truthiness, so argument at index 0 was ordered like plain option and help showed it after index 1
when that argument has `x-prompt` both are optional for yargs and values go to wrong argumnets, now positionals are sorted by index

(cherry picked from commit d69dcec)

Author: thekhegay

packages/angular/cli/src/command-builder/utilities/json-schema.ts

@@ -390,10 +390,10 @@ export async function parseJsonSchemaToOptions(
 
   // Sort by positional and name.
   return options.sort((a, b) => {
-    if (a.positional) {
-      return b.positional ? a.positional - b.positional : a.name.localeCompare(b.name);
-    } else if (b.positional) {
-      return -1;
+    if (a.positional !== undefined) {
+      return b.positional !== undefined ? a.positional - b.positional : -1;
+    } else if (b.positional !== undefined) {
+      return 1;
     }
 
     return a.name.localeCompare(b.name);

packages/angular/cli/src/command-builder/utilities/json-schema_spec.ts

@@ -345,4 +345,47 @@ describe('parseJsonSchemaToOptions', () => {
       );
     });
   });
+
+  describe('with positional arguments not in alphabetical order', () => {
+    it('sorts positional arguments by their index', async () => {
+      const jsonSchema = {
+        '$id': 'FakeSchema',
+        'title': 'Fake Schema',
+        'type': 'object',
+        'required': ['preset'],
+        'properties': {
+          'preset': {
+            'type': 'string',
+            'enum': ['form', 'table'],
+            'description': 'preset.',
+            '$default': {
+              '$source': 'argv',
+              'index': 0,
+            },
+            'x-prompt': 'Which preset?',
+          },
+          'name': {
+            'type': 'string',
+            'description': 'name.',
+            '$default': {
+              '$source': 'argv',
+              'index': 1,
+            },
+          },
+          'path': {
+            'type': 'string',
+            'description': 'path.',
+          },
+        },
+      };
+      const registry = new schema.CoreSchemaRegistry();
+      const options = await parseJsonSchemaToOptions(registry, jsonSchema, /* interactive= */ true);
+
+      expect(options).toEqual([
+        jasmine.objectContaining({ name: 'preset', positional: 0, required: false }),
+        jasmine.objectContaining({ name: 'name', positional: 1, required: false }),
+        jasmine.objectContaining({ name: 'path', positional: undefined, required: false }),
+      ]);
+    });
+  });
 });

tests/e2e/tests/generate/help-output.ts

@@ -32,22 +32,22 @@ export default function () {
         "$id": "FakeSchema",
         "title": "Fake Schema",
         "type": "object",
-        "required": ["a"],
+        "required": ["b"],
         "properties": {
           "b": {
             "type": "string",
             "description": "b.",
             "$default": {
               "$source": "argv",
-              "index": 1
+              "index": 0
             }
           },
           "a": {
             "type": "string",
             "description": "a.",
             "$default": {
               "$source": "argv",
-              "index": 0
+              "index": 1
             }
           },
           "optC": {
@@ -76,7 +76,7 @@ export default function () {
       )
       .then(() => ng('generate', 'fake-schematics:fake', '--help'))
       .then(({ stdout }) => {
-        assert.match(stdout, /ng generate fake-schematics:fake <a> \[b\]/);
+        assert.match(stdout, /ng generate fake-schematics:fake <b> \[a\]/);
         assert.match(stdout, /opt-a[\s\S]*opt-b[\s\S]*opt-c/);
       })
       // set up default collection.
@@ -89,7 +89,7 @@ export default function () {
       .then(() => ng('generate', 'fake', '--help'))
       // verify same output
       .then(({ stdout }) => {
-        assert.match(stdout, /ng generate fake <a> \[b\]/);
+        assert.match(stdout, /ng generate fake <b> \[a\]/);
         assert.match(stdout, /opt-a[\s\S]*opt-b[\s\S]*opt-c/);
       })