# https://golang.org/issue/46141: 'go mod tidy' for a Go 1.17 module should by
# default preserve enough checksums for the module to be used by Go 1.16.
#
# We don't have a copy of Go 1.16 handy, but we can simulate it by editing the
# 'go' version in the go.mod file to 1.16, without actually updating the
# requirements to match.

[short] skip

env MODFMT='{{with .Module}}{{.Path}} {{.Version}}{{end}}'


# For this module, the "deleted" dependency contains an imported package, but
# Go 1.16 selects a higher version (in which that package has been deleted).

cp go.mod go.mod.orig

! go mod tidy

stderr '^example\.com/m imports\n\texample\.net/deleted loaded from example\.net/deleted@v0\.1\.0,\n\tbut go 1\.16 would fail to locate it in example\.net/deleted@v0\.2\.0\n\n'

stderr '\n\nTo upgrade to the versions selected by go 1.16, leaving some packages unresolved:\n\tgo mod tidy -e -go=1\.16 && go mod tidy -e -go=1\.17\nIf reproducibility with go 1.16 is not needed:\n\tgo mod tidy -compat=1\.17\nFor other options, see:\n\thttps://golang\.org/doc/modules/pruning\n'


# The suggested 'go mod tidy -e' command should proceed anyway.

go mod tidy -e
cmp go.mod go.mod.tidy


# In 'go 1.16' mode we should error out in the way we claimed.

cd 116-outside
! go list -deps -f $MODFMT example.com/m
stderr '^\.\.[/\\]m\.go:4:2: no required module provides package example\.net/deleted; to add it:\n\tgo get example\.net/deleted$'
cd ..

go mod edit -go=1.16
! go list -deps -f $MODFMT example.com/m
stderr '^go: updates to go\.mod needed; to update it:\n\tgo mod tidy$'

! go mod tidy
stderr '^example\.com/m imports\n\texample\.net/deleted: module example\.net/deleted@latest found \(v0\.2\.0, replaced by \./d2\), but does not contain package example\.net/deleted$'


-- go.mod --
module example.com/m

go 1.17

replace (
	example.net/deleted v0.1.0 => ./d1
	example.net/deleted v0.2.0 => ./d2
	example.net/lazy v0.1.0 => ./lazy
	example.net/pruned v0.1.0 => ./pruned
)

require (
	example.net/deleted v0.1.0
	example.net/deleted v0.1.0 // redundant
	example.net/lazy v0.1.0
)
-- go.mod.tidy --
module example.com/m

go 1.17

replace (
	example.net/deleted v0.1.0 => ./d1
	example.net/deleted v0.2.0 => ./d2
	example.net/lazy v0.1.0 => ./lazy
	example.net/pruned v0.1.0 => ./pruned
)

require (
	example.net/deleted v0.1.0
	example.net/lazy v0.1.0
)
-- 116-outside/go.mod --
module outside

go 1.16

replace (
	example.com/m => ../
	example.net/deleted v0.1.0 => ../d1
	example.net/deleted v0.2.0 => ../d2
	example.net/lazy v0.1.0 => ../lazy
	example.net/pruned v0.1.0 => ../pruned
)

require example.com/m v0.1.0
-- m.go --
package m

import (
	_ "example.net/deleted"
	_ "example.net/lazy"
)

-- d1/go.mod --
module example.net/deleted

go 1.17
-- d1/deleted.go --
package deleted
-- d2/go.mod --
module example.net/deleted

go 1.17
-- d2/README --
There is no longer a Go package here.

-- lazy/go.mod --
module example.net/lazy

go 1.17

require example.net/pruned v0.1.0
-- lazy/lazy.go --
package lazy

-- pruned/go.mod --
module example.net/pruned

go 1.17

require example.net/deleted v0.2.0