tree 89dc249b84488929d5fe0bc653151d15b78541b7
parent 8188ccf5f653d2c110a4196861288f96607ddf56
author Googler <noreply@google.com> 1590772949 -0700
committer Copybara-Service <copybara-worker@google.com> 1590773026 -0700

Forward InstrumentedFilesProvider from all dependencies by default (conditioned on flag)

Currently, the entire dependency chain between a test and whatever rule compiles the source files must provide InstrumentedFilesInfo. Getting coverage correct for a given language requires not only rules that handle source files in that language to be correctly configured, but all rules in the dependency chain between the test and the source files must explicitly support coverage collection.

Often, a rule's immediate dependencies are all one of:
* Source files (which don't provide InstrumentedFilesProvider)
* Rule targets which might provide either code or binaries which might be executed at runtime

In those cases, forwarding InstrumentedFilesProvider from the dependencies is the correct behavior. Tool dependencies (ones in host/exec config) can be excluded, since code/binaries provided by those dependencies are not executed at runtime.

If InstrumentedFilesProvider is forwarded from a dependency incorrectly and something in that dependency's transitive dependencies is matched by --instrumentation_filter, the downside is that the user may end up with correct runtime coverage data for an overly-large list of source files. The extraneous entries will note there is no coverage data for that file. That seems possibly better than the downside of the current default, that coverage data which could be correctly gathered is potentially omitted.

The new behavior is enabled with the flag --experimental_forward_instrumented_files_info_by_default.

RELNOTES: Add experiment flag to forward InstrumentedFilesInfo from non-tool deps by default.
PiperOrigin-RevId: 313804469