Access to runtime_deps at build-time

[arvid.g...@gmail.com]

The `runtime_deps` system is amazing, I can collect all the dependencies and build a package out of them for distribution.
However, to do so I have to rely on an external python script, which takes the generated file (generated via `write_runtime_deps` of a target) and creates a bundle (either the parts of a .app, on macOS, or a folder with a directory structure on Windows, Linux). This has one huge disadvantage, which I dislike a lot: it's circumventing the build systems dependency tree, I have to list a non-existant stamp file as input dependency for the action invoking the python script, since neither ninja nor gn know about the output files.
I tried to access the generated file at build time, but since all runtime dep files are written at the end of generation, this is impossible.

Is there any way I could achieve that GN knows about the files? That'd be great, and would eliminate, for example, the custom clean script (since ninja doesn't know about the output files, either), or re-running the build step every time, even though nothing changed.

- Arvid

[Brett Wilson]

There isn't an ordering for the loading of BUILD files, so GN won't know the dependency tree until after the script as run. As a trivial example, say your target has a dependency on a target defined below it in the same file, the script will have no way of knowing what that later target brings in.

Brett 

[Dirk Pranke]

Can you list the file written by write_runtime_deps() as an input to the target that creates the bundle?

-- Dirk