fix: Simple hosted dependencies should be inlined (#795)

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## Description

Before this fix (after moving to pubspec_parse), when we updated shared
dependencies they would explicitly use the version field.

Example before this PR:
```yaml
dependencies:
  flame:
    version: ^1.21.0
```

After this PR:
```yaml
dependencies:
  flame: ^1.21.0
```

## Type of Change

<!--- Put an `x` in all the boxes that apply: -->

- [ ] ✨ `feat` -- New feature (non-breaking change which adds
functionality)
- [x] 🛠️ `fix` -- Bug fix (non-breaking change which fixes an issue)
- [ ] ❌ `!` -- Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] 🧹 `refactor` -- Code refactor
- [ ] ✅ `ci` -- Build configuration change
- [ ] 📝 `docs` -- Documentation
- [ ] 🗑️ `chore` -- Chore

packages/melos/lib/src/common/extensions/dependency.dart

@@ -9,6 +9,18 @@ extension DependencyExtension on Dependency {
     return null;
   }
 
+  /// Whether the json can be inlined with its parent.
+  ///
+  /// For example for [HostedDependency] the version shouldn't be on a separate
+  /// line when only the version is defined.
+  bool get inlineVersion {
+    if (this is HostedDependency) {
+      return (this as HostedDependency).hosted == null &&
+          versionConstraint != null;
+    }
+    return false;
+  }
+
   Object toJson() {
     final self = this;
     if (self is PathDependency) {
@@ -34,15 +46,17 @@ extension PathDependencyExtension on PathDependency {
 }
 
 extension HostedDependencyExtension on HostedDependency {
-  Map<String, dynamic> toJson() {
-    return {
-      'version': version.toString(),
-      if (hosted != null)
-        'hosted': {
-          'name': hosted!.declaredName,
-          'url': hosted!.url?.toString(),
-        },
-    };
+  Object toJson() {
+    return inlineVersion
+        ? version.toString()
+        : {
+            'version': version.toString(),
+            if (hosted != null)
+              'hosted': {
+                'name': hosted!.declaredName,
+                'url': hosted!.url?.toString(),
+              },
+          };
   }
 }
 

packages/melos/test/commands/bootstrap_test.dart

@@ -4,11 +4,13 @@ import 'package:melos/melos.dart';
 import 'package:melos/src/command_configs/command_configs.dart';
 import 'package:melos/src/commands/runner.dart';
 import 'package:melos/src/common/glob.dart';
+import 'package:melos/src/common/io.dart';
 import 'package:melos/src/common/utils.dart';
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 import 'package:pubspec_parse/pubspec_parse.dart';
 import 'package:test/test.dart';
+import 'package:yaml/yaml.dart';
 
 import '../matchers.dart';
 import '../utils.dart';
@@ -745,7 +747,7 @@ Generating IntelliJ IDE files...
     });
 
     test(
-      'applies dependencies from melos config',
+      'applies shared dependencies from melos config',
       () async {
         final workspaceDir = await createTemporaryWorkspace(
           configBuilder: (path) => MelosWorkspaceConfig(
@@ -910,6 +912,51 @@ Generating IntelliJ IDE files...
       },
       timeout: const Timeout(Duration(days: 2)),
     );
+
+    test('correctly inlines shared dependencies', () async {
+      final workspaceDir = await createTemporaryWorkspace(
+        configBuilder: (path) => MelosWorkspaceConfig.fromYaml(
+          createYamlMap(
+            {
+              'command': {
+                'bootstrap': {
+                  'dependencies': {
+                    'flame': '^1.21.0',
+                  },
+                },
+              },
+            },
+            defaults: configMapDefaults,
+          ),
+          path: path,
+        ),
+      );
+
+      final pkgA = await createProject(
+        workspaceDir,
+        Pubspec(
+          'a',
+          dependencies: {
+            'flame': HostedDependency(version: VersionConstraint.any),
+          },
+        ),
+      );
+
+      final logger = TestLogger();
+      final config = await MelosWorkspaceConfig.fromWorkspaceRoot(workspaceDir);
+      final melos = Melos(
+        logger: logger,
+        config: config,
+      );
+
+      await runMelosBootstrap(melos, logger);
+
+      final pubspecContent = _pubspecContent(pkgA);
+      expect(
+        (pubspecContent['dependencies']! as YamlMap)['flame'],
+        '^1.21.0',
+      );
+    });
   });
 
   group('melos bs --skip-linking', () {
@@ -1142,3 +1189,8 @@ Future<void> dependencyResolutionTest(
 
   await Future.wait<void>(packages.keys.map(validatePackage));
 }
+
+YamlMap _pubspecContent(io.Directory directory) {
+  final source = readTextFile(pubspecPath(directory.path));
+  return loadYaml(source) as YamlMap;
+}

packages/melos/test/utils.dart

@@ -219,6 +219,10 @@ String packageConfigPath(String packageRoot) {
   );
 }
 
+String pubspecPath(String directory) {
+  return p.join(directory, 'pubspec.yaml');
+}
+
 PackageConfig packageConfigForPackageAt(Directory dir) {
   final source = readTextFile(packageConfigPath(dir.path));
   return PackageConfig.fromJson(json.decode(source) as Map<String, Object?>);