# This test illustrates the interaction between lazy loading and downgrading in
# 'go get.

# The package import graph used in this test looks like:
#
# lazy ---- a
#           |
#           a_test ---- b
#                       b_test ---- c
#
# The module dependency graph initially looks like:
#
# lazy ---- a.1 ---- b.1 ---- c.1
#      \                     /
#        b.3 ---- c.2    b.2
#
# (Note that lazy loading will prune out the dependency from b.1 on c.1.)

cp go.mod go.mod.orig
go mod tidy
cmp go.mod.orig go.mod

go list -m all
stdout '^example.com/a v0.1.0 '
stdout '^example.com/b v0.3.0 '
stdout '^example.com/c v0.2.0 '

# Downgrading c should also downgrade the b that requires it.

go get -d example.com/c@v0.1.0
go list -m all
stdout '^example.com/a v0.1.0 '
stdout '^example.com/b v0.2.0 '
stdout '^example.com/c v0.1.0 '

# Removing c entirely should also remove the a and b that require it.

go get -d example.com/c@none
go list -m all
! stdout '^example.com/a '
! stdout '^example.com/b '
! stdout '^example.com/c '


# With lazy loading, downgrading c should work the same way, but dependencies
# outside of the deepening scan should not affect the downgrade.

cp go.mod.orig go.mod
go mod edit -go=1.16

go list -m all
stdout '^example.com/a v0.1.0 '
stdout '^example.com/b v0.3.0 '
stdout '^example.com/c v0.2.0 '

go get -d example.com/c@v0.1.0
go list -m all
stdout '^example.com/a v0.1.0 '
stdout '^example.com/b v0.2.0 '
stdout '^example.com/c v0.1.0 '

go get -d example.com/c@none
go list -m all
! stdout '^example.com/a '  # TODO(#36460): example.com/a v0.1.0
! stdout '^example.com/b '  # TODO(#36460): example.com/b v0.1.0
! stdout '^example.com/c '

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

go 1.15

require (
	example.com/a v0.1.0
	example.com/b v0.3.0 // indirect
)

replace (
	example.com/a v0.1.0 => ./a
	example.com/b v0.1.0 => ./b1
	example.com/b v0.2.0 => ./b2
	example.com/b v0.3.0 => ./b3
	example.com/c v0.1.0 => ./c
	example.com/c v0.2.0 => ./c
)
-- lazy.go --
package lazy

import _ "example.com/a"

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

go 1.15

require example.com/b v0.1.0
-- a/a.go --
package a
-- a/a_test.go --
package a_test

import _ "example.com/b"

-- b1/go.mod --
module example.com/b

go 1.15

require example.com/c v0.1.0
-- b1/b.go --
package b
-- b1/b_test.go --
package b_test
import _ "example.com/c"

-- b2/go.mod --
module example.com/b

go 1.15

require example.com/c v0.1.0
-- b2/b.go --
package b
-- b2/b_test.go --
package b_test
import _ "example.com/c"

-- b3/go.mod --
module example.com/b

go 1.15

require example.com/c v0.2.0
-- b3/b.go --
package b
-- b3/b_test.go --
package b_test
import _ "example.com/c"

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

go 1.15
-- c/c.go --
package c