Error early when using conflicting architectures

.changeset/witty-cats-admire.md

@@ -0,0 +1,5 @@
+---
+"cmake-rn": patch
+---
+
+Error early when using conflicting architectures for across triplets

packages/cmake-rn/src/cli.ts

@@ -250,6 +250,9 @@ program = program.action(
             platformHasTriplet(platform, triplet),
           );
           if (relevantTriplets.length > 0) {
+            platform.assertValidTriplets(
+              relevantTriplets.map(({ triplet }) => triplet),
+            );
             await platform.configure(
               relevantTriplets,
               baseOptions,

packages/cmake-rn/src/platforms/android.ts

@@ -122,6 +122,7 @@ export const platform: Platform<Triplet[], AndroidOpts> = {
       .addOption(ndkVersionOption)
       .addOption(androidSdkVersionOption);
   },
+  assertValidTriplets() {},
   async configure(
     triplets,
     {

packages/cmake-rn/src/platforms/apple.ts

@@ -4,6 +4,7 @@ import fs from "node:fs";
 import cp from "node:child_process";
 
 import {
+  assertFixable,
   Option,
   oraPromise,
   prettyPath,
@@ -193,6 +194,12 @@ async function readCmakeSharedLibraryTarget(
   return sharedLibrary;
 }
 
+const SIMULATOR_TRIPLET_SUFFIXES = [
+  "apple-ios-sim",
+  "apple-tvos-sim",
+  "apple-visionos-sim",
+] as const;
+
 export const platform: Platform<Triplet[], AppleOpts> = {
   id: "apple",
   name: "Apple",
@@ -243,6 +250,35 @@ export const platform: Platform<Triplet[], AppleOpts> = {
       .addOption(xcframeworkExtensionOption)
       .addOption(appleBundleIdentifierOption);
   },
+  assertValidTriplets(triplets) {
+    for (const suffix of SIMULATOR_TRIPLET_SUFFIXES) {
+      const suggestion = `use the universal 'arm64;x86_64-${suffix}' triplet instead`;
+      assertFixable(
+        !triplets.includes(`x86_64-${suffix}`) ||
+          !triplets.includes(`arm64-${suffix}`),
+        `Conflicting triplet variants for ${suffix}`,
+        {
+          instructions: `Remove either the arm64 or x86_64 variant of the ${suffix} triplet or ${suggestion}`,
+        },
+      );
+      assertFixable(
+        !triplets.includes(`x86_64-${suffix}`) ||
+          !triplets.includes(`arm64;x86_64-${suffix}`),
+        `Conflicting triplet variants for ${suffix}`,
+        {
+          instructions: `Remove the x86_64 variant of the ${suffix} triplet and ${suggestion}`,
+        },
+      );
+      assertFixable(
+        !triplets.includes(`arm64-${suffix}`) ||
+          !triplets.includes(`arm64;x86_64-${suffix}`),
+        `Conflicting triplet variants for ${suffix}`,
+        {
+          instructions: `Remove the arm64 variant of the ${suffix} triplet and ${suggestion}`,
+        },
+      );
+    }
+  },
   async configure(
     triplets,
     { source, build, define, weakNodeApiLinkage, cmakeJs },

packages/cmake-rn/src/platforms/types.ts

@@ -53,6 +53,11 @@ export type Platform<
   defaultTriplets(
     mode: "current-development" | "all",
   ): Triplet[] | Promise<Triplet[]>;
+  /**
+   * Assert the combination of triplets is supported by the platform.
+   * @throws {Error} If the combination of triplets is not supported.
+   */
+  assertValidTriplets(triplets: Triplet[]): void;
   /**
    * Implement this to add any platform specific options to the command.
    */