tree 5f45f6aabff3cca671d45277ce1f80be2b4529bb
parent 02048e6c24c4b42259768e08e3fad4fc9e2882d3
author Alan Donovan <adonovan@google.com> 1698098655 -0400
committer Robert Findley <rfindley@google.com> 1698157062 +0000

go/packages: ensure that types.Sizes is correct

This change ensures that types.Sizes information can
be computed from compiler+GOARCH if it is needed;
if not, it causes the Load to fail.

This fixes a crash in gopls whereby a bad GOARCH
causes the types.Sizes to be silently nil, in violation
of the Packages.TypesSizes contract. Gopls would
then dereference this nil.

The problem only manifests with a file=foo.go
query, as this suppresses go list's usual eager check for
valid GOOS/GOARCH during its build tag computation.
gopls relies on the file=... mode as a fall back.

Note that this change reverts my earlier doc
change today that allowed TypesSizes to be nil
if unknown. This was the wrong fix, as it
creates both a nil-dereference hazard (the
original bug), plus, if the nil Sizes is fed to
go/types.Config, it would trigger the default
(wrong) size computation.
(This is less significant to gopls because
in file=... mode, size errors are the least of
your type-error worries, but still...)

Plus, a test.

Also: simplify two trivially true conditions
in the packages.Load control flow.

Fixes golang/go#63701
Fixes golang/vscode-go#3021

Change-Id: I8d519d0d8a8c7bce6b3206a8116a150d37e74e45
Reviewed-on: https://go-review.googlesource.com/c/tools/+/537118
Reviewed-by: Robert Findley <rfindley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>