ardupilotwaf: remove legacy source header dependency scanning logic #31419
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Due to the slowness of waf's source header dependency scanner, logic was introduced to avoid deleting the results during a `./waf clean`. However, this logic has not done anything since switching to the gccdeps scanner (to speed scanning up) many years ago. That overrides the `sig_implicit_deps` method too and results in `_original_sig_implicit_deps != real_fn` always being true and the custom logic never activating. There's little reason to use the default dependency scanner anymore. Since the logic is complex, not necessary, and doesn't work in that case, just delete it. Timings of CubeOrange build: before, fresh git tree, gccdeps: 2m3s before, `./waf clean`, gccdeps: 2m2s before, fresh git tree, default: 2m26s before, `./waf clean`, default: 2m2s after, fresh git tree, gccdeps: 2m3s after, `./waf clean`, gccdeps: 2m3s after, fresh git tree, default: 2m28s after, `./waf clean`, default: 2m27s
There is essentially no reason to use the slower default, the option to do so was only added many years ago to smooth working with older branches which did use the default. But those haven't been around for a long time so just delete the option.
tridge
approved these changes
Nov 4, 2025
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waf has built in logic to scan your source files and automatically add dependencies on the included files. It also supports using GCC to do this.
Long long ago:
But today, seven years later, essentially nobody works with such old branches and nobody's run into issues with GCC's scanner. So we can remove the option to switch to waf's scanner then delete the complex logic from #4590 which has been disabled by default for seven years and only helped waf's scanner anyway.
Confirmed that there is no performance reduction and no compiler output change.
Timings of CubeOrange copter build: