feat(cli): support SPM package traits in generated Package.swift

cli/src/declarations.ts

@@ -536,11 +536,29 @@ export interface CapacitorConfig {
          *
          * This setting may graduate to `ios.spm.swiftToolsVersion` in a future major release.
          *
-         * @since 8.2.0
+         * @since 8.3.0
          * @default '5.9'
          * @example '6.1'
          */
         swiftToolsVersion?: string;
+
+        /**
+         * Define package traits for SPM plugin dependencies.
+         *
+         * This requires explicitly setting experimental.ios.spm.swiftToolsVersion
+         * to '6.1' or higher.
+         *
+         * The key is the plugin ID (e.g. `@capacitor-firebase/analytics`)
+         * and the value is an array of trait names.
+         *
+         * Packages can have default traits. If you use this property, and
+         * want to preserve the defaults, include ".defaults" in the array.
+         *
+         * This setting may graduate to `ios.spm.packageTraits` in a future major release.
+         *
+         * @since 8.3.0
+         */
+        packageTraits?: { [pluginId: string]: string[] };
       };
     };
   };

cli/src/ios/common.ts

@@ -11,7 +11,7 @@ import type { Config } from '../definitions';
 import { logger } from '../log';
 import { PluginType, getPluginPlatform } from '../plugin';
 import type { Plugin } from '../plugin';
-import { checkSwiftToolsVersion } from '../util/spm';
+import { checkPackageTraitsRequirements, checkSwiftToolsVersion } from '../util/spm';
 import { isInstalled, runCommand } from '../util/subprocess';
 
 export async function checkIOSPackage(config: Config): Promise<string | null> {
@@ -38,6 +38,7 @@ export async function getCommonChecks(config: Config): Promise<CheckFunction[]>
     if (swiftToolsVersion) {
       checks.push(() => checkSwiftToolsVersion(config, swiftToolsVersion));
     }
+    checks.push(() => checkPackageTraitsRequirements(config));
   }
   return checks;
 }

cli/src/util/spm.ts

@@ -98,6 +98,7 @@ export async function removeCocoapodsFiles(config: Config): Promise<void> {
 export async function generatePackageText(config: Config, plugins: Plugin[]): Promise<string> {
   const iosPlatformVersion = await getCapacitorPackageVersion(config, config.ios.name);
   const iosVersion = getMajoriOSVersion(config);
+  const packageTraits = config.app.extConfig.experimental?.ios?.spm?.packageTraits ?? {};
   const swiftToolsVersion = config.app.extConfig.experimental?.ios?.spm?.swiftToolsVersion ?? '5.9';
 
   let packageSwiftText = `// swift-tools-version: ${swiftToolsVersion}
@@ -120,7 +121,16 @@ let package = Package(
       packageSwiftText += `,\n        .package(name: "${plugin.name}", path: "../../capacitor-cordova-ios-plugins/sources/${plugin.name}")`;
     } else {
       const relPath = relative(config.ios.nativeXcodeProjDirAbs, plugin.rootPath);
-      packageSwiftText += `,\n        .package(name: "${plugin.ios?.name}", path: "${relPath}")`;
+      const traits = packageTraits[plugin.id];
+      const traitsSuffix = traits?.length
+        ? `, traits: [${traits
+            .map((t) => {
+              // Any trait is written with quotes, with the exception of .defaults
+              return /^\.?defaults?$/i.test(t) ? '.defaults' : `"${t}"`;
+            })
+            .join(', ')}]`
+        : '';
+      packageSwiftText += `,\n        .package(name: "${plugin.ios?.name}", path: "${relPath}"${traitsSuffix})`;
     }
   }
 
@@ -206,6 +216,37 @@ export async function checkSwiftToolsVersion(config: Config, version: string | u
   return null;
 }
 
+export async function checkPackageTraitsRequirements(config: Config): Promise<string | null> {
+  const packageTraits = config.app.extConfig.experimental?.ios?.spm?.packageTraits;
+  const swiftToolsVersion = config.app.extConfig.experimental?.ios?.spm?.swiftToolsVersion;
+
+  const hasPackageTraits = packageTraits && Object.keys(packageTraits).some((key) => packageTraits[key]?.length > 0);
+
+  if (!hasPackageTraits) {
+    return null;
+  }
+
+  if (!swiftToolsVersion) {
+    return (
+      `Package traits require an explicit Swift tools version of 6.1 or higher.\n` +
+      `Set experimental.ios.spm.swiftToolsVersion to '6.1' or higher in your Capacitor configuration.`
+    );
+  }
+
+  const versionParts = swiftToolsVersion.split('.').map((part) => parseInt(part, 10));
+  const major = versionParts[0] || 0;
+  const minor = versionParts[1] || 0;
+
+  if (major < 6 || (major === 6 && minor < 1)) {
+    return (
+      `Package traits require Swift tools version 6.1 or higher, but "${swiftToolsVersion}" was specified.\n` +
+      `Update experimental.ios.spm.swiftToolsVersion to '6.1' or higher in your Capacitor configuration.`
+    );
+  }
+
+  return null;
+}
+
 // Private Functions
 
 async function pluginsWithPackageSwift(plugins: Plugin[]): Promise<Plugin[]> {