ref(nextjs): Simplify isBuild logic (#6594)

Author: lforst

packages/nextjs/src/utils/isBuild.ts

@@ -4,27 +4,5 @@ import { NEXT_PHASE_PRODUCTION_BUILD } from './phases';
  * Decide if the currently running process is part of the build phase or happening at runtime.
  */
 export function isBuild(): boolean {
-  if (
-    // During build, the main process is invoked by
-    //   `node next build`
-    // and child processes are invoked as
-    //   `node <path>/node_modules/.../jest-worker/processChild.js`.
-    // The former is (obviously) easy to recognize, but the latter could happen at runtime as well. Fortunately, the main
-    // process hits this file before any of the child processes do, so we're able to set an env variable which the child
-    // processes can then check. During runtime, the main process is invoked as
-    //   `node next start`
-    // or
-    //   `node /var/runtime/index.js`,
-    // so we never drop into the `if` in the first place.
-    process.argv.includes('build') ||
-    process.env.SENTRY_BUILD_PHASE ||
-    // This is set by next, but not until partway through the build process, which is why we need the above checks. That
-    // said, in case this function isn't called until we're in a child process, it can serve as a good backup.
-    process.env.NEXT_PHASE === NEXT_PHASE_PRODUCTION_BUILD
-  ) {
-    process.env.SENTRY_BUILD_PHASE = 'true';
-    return true;
-  }
-
-  return false;
+  return process.env.NEXT_PHASE === NEXT_PHASE_PRODUCTION_BUILD;
 }