build_web_compilers don't work in aot mode

[schultek]

I came across this while trying the new build_runner aot mode for Jaspr.

build_web_compilers and other related packages don't seem to support that as of now, and I couldn't find an existing issue.

---

Reproducible with:

• Create a new dart web project with dart create -t web myproject
• Update build_runner dependency to ^2.10.0
• Run dart run build_runner build --force-aot

You will see the following error:

build_web_compilers|$package$ build_web_compilers:sdk_js (lazy)                      
E Null check operator used on a null value                                           
  #0      scratchSpaceResource.<anonymous closure>                                   
  (package:build_modules/src/scratch_space.dart:36)                                  
  <asynchronous suspension>                                                          
  #1      Resource._fetch.<anonymous closure> (package:build/src/resource.dart:104)  
  <asynchronous suspension>                                                          
  #2      _createDevCompilerModule                                                   
  (package:build_web_compilers/src/sdk_js_compile_builder.dart:88)                   
  <asynchronous suspension>                                                          
  #3      SdkJsCompileBuilder.build                                                  
  (package:build_web_compilers/src/sdk_js_compile_builder.dart:68)                   
  <asynchronous suspension>                                                          
  #4      runBuilder.buildForInput                                                   
  (package:build_runner/src/build/run_builder.dart:85)                               
  <asynchronous suspension>                                                          
  #5      Future.wait.<anonymous closure> (dart:async/future.dart:525)               
  <asynchronous suspension>                                                          
  #6      BuildLogLogger.scopeLogAsync.<anonymous closure>                           
  (package:build_runner/src/logging/build_log_logger.dart:58)                        
  <asynchronous suspension>       

• The Dart SDK Version: 3.10.0-162.1.beta (beta) (Mon Sep 1 23:24:50 2025 -0700) on "macos_x64"

[davidmorgan]

Thanks!

I think the problem is this line in build_modules/lib/src/scratch_space.dart

      final originalConfigFile = File.fromUri((await Isolate.packageConfig)!);