Large number of build_runner inputs when using modular generation

[js2702]

We have a big Flutter project where we've been using Drift for a long time. Over the years build_runner builds have been taking a bit hit on our CI times. We've been trying to optimize it by using a lower number of transitive imports from the build entry points.

We've noticed that even when lowering this number of imports to a minimum, the Drift modular generation of our code is showing a large number of inputs (1K), and it takes about 30 seconds to analyze.

We are using the latest build_runner 2.5.x, which has many new optimizations in place. When going back to the non modular a low number of inputs shows up. Could this be a bug in the modular generation feature?

[simolus3]

Thanks for the report! Yeah, the modular builder is not supposed to have that many inputs. I'm actually not sure what the amount of inputs in the output is referring to though - if it's the amount of files drift ran on, that's not really something under our control.

When going back to the non modular a low number of inputs shows up

Just for my interest, how many? Also, how many inputs do you see for drift_dev:preparing_builder and drift_dev:analyzer?

[js2702]

With the no modular build we are getting the following output:

❯ dart run build_runner build --delete-conflicting-outputs
Building package executable... (2.3s)
Built build_runner:build_runner.
26s mobx_codegen:mobx_generator on 2 inputs: 2 output; spent 18s analyzing, 4s resolving, 3s sdk                                                                  
0s freezed on 5 inputs: 5 same                                                                                                                                    
1s json_serializable on 9 inputs: 5 output, 4 no-op                                                                                                               
0s envied_generator:envied on 1 input: 1 output                                                                                                                   
0s drift_dev:preparing_builder on 4 inputs: 4 output                                                                                                              
1s drift_dev on 44 inputs: 37 output, 7 no-op                                                                                                                     
0s built_value_generator:built_value on 32 inputs: 13 output, 19 no-op                                                                                            
0s source_gen:combining_builder on 532 inputs: 4 skipped, 15 no-op; lib/data/database/daos/deck_card_tags/deck_card_tags_dao.dart                                 

And with the modular approach:

❯ dart run build_runner build --delete-conflicting-outputs
Building package executable... (2.3s)
Built build_runner:build_runner.
0s drift_dev:preparing_builder on 4 inputs: 4 output                                                                                                              
35s drift_dev:analyzer on 1010 inputs: 961 output, 49 no-op; spent 24s analyzing, 5s resolving, 4s sdk, 2s building                                               
1s drift_dev:modular on 16 inputs: 10 same, 6 no-op                                                                                                               
1s mobx_codegen:mobx_generator on 2 inputs: 2 output                                                                                                              
0s freezed on 5 inputs: 5 same                                                                                                                                    
1s json_serializable on 9 inputs: 5 output, 4 no-op                                                                                                               
0s envied_generator:envied on 1 input: 1 output                                                                                                                   
0s built_value_generator:built_value on 62 inputs: 30 skipped, 13 output, 19 no-op                                                                                
1s source_gen:combining_builder on 1027 inputs: 511 skipped, 21 output, 495 no-op                                                                                 
                                                                                                                                                                  
Built with build_runner in 41s; wrote 1026 outputs.                                                                                                               
                                                                                                                                                                  
log output for build_runner                                                                                                                                       
  Deleting 36 declared outputs which already existed on disk.                                                                                                     

We are also not sure what it means. We are trying to optimize the builds so it doesn't process everything.