Is There Support to Force-Rebuild a File?

[PvtPuddles]

Hello,

I would like to add a file to my build.yaml to always re-process a file when build is run. It does not appear that this is supported, but I wasn't sure so I wanted to start a discussion before opening an issue.

For context, I am using the Dart OpenAPI Generator, which has an annotation that triggers the code generator. (Why they don't just use a openapi.yaml is beyond me).

The problem exists that build_runner will only trigger the OpenAPI builder if the file with the annotation is re-processed (IE: the file has been changed). The OpenAPI generator works around this issue by adding a "last run" timestamp and updating it every time build_runner runs. This causes a lot of churn and results in merge conflicts when working in a team.

From the Openapi annotation's forceAlwaysRun property:

If true, the annotated file will be modified after code generation completes.

This is a workaround to ensure this library runs every time you execute the build_runner command.

Why modify the file?

build_runner only processes files that have changed since the last run. By modifying the file, you
force build_runner to recognize it as changed and re-run the generation process.

Note: Setting this to true can lead to merge conflicts in team environments,
as each developer may end up modifying the annotated file.

Is there a way I can force build_runner to always reprocess this single file?

[davidmorgan]

I'm a bit puzzled about why it needs to run again.

build_runner will run if the input has changed or the output is disappeared. So it should always run if it's needed.

Is the generator doing some other work unrelated to the build, maybe?

[PvtPuddles]

Apologies, I forgot to mention that the OpenAPI generator reads an API spec from a .yaml or .json file.

Changes in the API spec don't trigger the Openapi generator since the generator is triggered by this other file, which wasn't modified.

[davidmorgan]

build_runner tracks additional inputs so that it knows to rerun when those change, too.

But it can only do this for file accessed via its APIs :) ... it looks like the generator runs a CLI, so build_runner won't find out about it.

It looks like this should be easy to add: the generator should call buildStep.canRead for every file it cares about, to let build_runner know.

[PvtPuddles]

Okay! Thank you, I'll open an issue to do that over there.

In the meantime, it sounds like there's not a good way to work around this on the user-end?

[davidmorgan]

Great, thanks :)

You could delete the output to force one generation to rerun, or delete .dart_tool/build/*/asset_graph.json to force all generation in the package to rerun. Neither seems particularly convenient though :)