# Verifies golang.org/issue/37574.

# If we are already using an +incompatible version, we shouldn't look up
# a lower compatible version when upgrading.
cp go.mod go.mod.orig
go mod tidy
cmp go.mod.orig go.mod
grep '^example.com/incompatiblewithsub v2\.0\.0\+incompatible' go.sum
! grep '^example.com/incompatiblewithsub v1.0.0' go.sum

go get -d example.com/incompatiblewithsub/sub
cmp go.mod.orig go.mod
! grep '^example.com/incompatiblewithsub v1.0.0' go.sum

# TODO(golang.org/issue/31580): the 'go get' command above should not change
# go.sum. However, as part of the query above, we download example.com@v1.0.0,
# an unrelated module, since it's a possible prefix. The sum for that module
# should not be written to go.sum.

-- go.mod --
module m

go 1.15

require example.com/incompatiblewithsub v2.0.0+incompatible
-- use.go --
package use

import _ "example.com/incompatiblewithsub/sub"