tree 7d9ccae2e9e22b472c62c21f584bfff7f6ff9e84
parent 1740f5c25bcac5a650ee3d1c1ec22bfa25fcd756
author Peter Collingbourne <pcc@google.com> 1776817459 -0700
committer gn-scoped@luci-project-accounts.iam.gserviceaccount.com <gn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1777668112 -0700

Fix toolchain dependencies not triggering rebuilds in Ninja

GN previously emitted order-only dependencies on toolchain dependencies
(via the .inputdeps.stamp file). This meant that if the toolchain changed,
targets compiled by it were not rebuilt.

This change modifies WriteInputDepsStampOrPhonyAndGetDep (WIDSOPAGD)
to return implicit dependencies separately from order-only
dependencies. Toolchain dependencies are now returned as implicit
dependencies, which ensures that Ninja triggers a rebuild when the
toolchain changes.

All target writers have been updated to write the result of WIDSOPAGD as
either implicit or order-only dependencies. The action target writer is
a special case, because before this change it would write the result of
WIDSOPAGD as an implicit dependency, unlike all other target writers,
which would write it as an order-only dependency. This means that before
this change, all dependencies returned by WIDSOPAGD were implicit
dependencies for action targets. Because scripts may depend on this
behavior, any phony targets created by WIDSOPAGD for action targets have
only implicit dependencies.

Bug: 40643484
Change-Id: Iae5dbf87cd67ecd5c9d0f6138f17085233c844b3
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/22000
Reviewed-by: Takuto Ikuta <tikuta@google.com>
Commit-Queue: Peter Collingbourne <pcc@google.com>