The runtime/trace package proved useful for investigating go command
performance, and it makes sense (to me) to make this available for
development behind an undocumented flag, at the cost of ~25KB of binary
size. We could of course futher hide this functionality behind an
experiment or build tag, if necessary.

Updates #59157

Change-Id: I612320920ca935f1ee10bb6a803b7952f36c939b
Reviewed-on: https://go-review.googlesource.com/c/go/+/477896
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Robert Findley <rfindley@google.com>

Instead, do the cycle checking in recompileForTest once the test
variant packages have been poked in the right places in the dependency
tree(graph?).

(Pair programming with bcmills@.)

For #59157.

Change-Id: I0c644cb9f2c0dac3a5b0189e2aa0eef083c669f6
Reviewed-on: https://go-review.googlesource.com/c/go/+/482237
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>

Go list is being updated to produce an error on the importing package,
rather than the imported package when there is an invalid import (such
as of a internal package, or of a vendored package but with the wrong
import path). This new error will produce a new diagnostic which is
causing the builders to fail on that change. This change updates the
tests to expect the new go list error on 1.21.

I'm not sure how to update the tests to work both before and after
that change. We can maybe change the golden diagnostic count summary
comparison to be disabled from this cl until the new cl is submitted,
but I'd like to see if I'm missing a better solution.

For golang/go#59157

Change-Id: I340dcddfd37edc4fc53aa9008eabd22366c34f2a
Reviewed-on: https://go-review.googlesource.com/c/tools/+/483016
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>

And assign the error to the importing package. Before this change, for
some errors for bad imports, such as importing a vendored package with
the wrong path, we would make a dummy package for the imported package
with the error on it. Instead report the error on the importing
package where it belongs. Do so by returning an error from loadImport
and handling it on the importing package.

For #59157

Change-Id: I952e1a82af3857efc5da4fd3f8bc6be473a60cf5
Reviewed-on: https://go-review.googlesource.com/c/go/+/482877
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

Stop depending on DepsErrors to report errors to the user and instead
only use it and compute it in list. Instead, use Incomplete to figure
out when a package or its depencies have an error, and only if they
do, do the work of finding all those errors.

For #59157

Change-Id: Ied927f53e7b1f66fad9248b40dd11ed960b3ef91
Reviewed-on: https://go-review.googlesource.com/c/go/+/483495
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>

Now that go list reports import errors on the importing package,
update the disabled part of the test to expect that error. (We
commented out the line generating the diagnostic in the test before
making the change so that the change itself wouldn't generate a
diagnostic and break the test).

For golang/go#59157

Change-Id: I207f507c8e07dd55d3609ca2bb9bdf25528ec898
Reviewed-on: https://go-review.googlesource.com/c/tools/+/482999
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>