1 files changed, 56 insertions, 0 deletions
diff --git a/src/cmd/go/testdata/script/mod_get_downgrade.txt b/src/cmd/go/testdata/script/mod_get_downgrade.txt
new file mode 100644
index 0000000..2eed56d
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_get_downgrade.txt
@@ -0,0 +1,56 @@
+env GO111MODULE=on
+[short] skip
+
+# downgrade sampler should downgrade quote
+cp go.mod.orig go.mod
+go get rsc.io/sampler@v1.0.0
+go list -m all
+stdout 'rsc.io/quote v1.4.0'
+stdout 'rsc.io/sampler v1.0.0'
+
+# downgrade sampler away should downgrade quote further
+go get rsc.io/sampler@none
+go list -m all
+stdout 'rsc.io/quote v1.3.0'
+
+# downgrade should report inconsistencies and not change go.mod
+go get rsc.io/quote@v1.5.1
+go list -m all
+stdout 'rsc.io/quote v1.5.1'
+stdout 'rsc.io/sampler v1.3.0'
+
+! go get rsc.io/sampler@v1.0.0 rsc.io/quote@v1.5.2 golang.org/x/text@none
+! stderr add|remove|upgrad|downgrad
+stderr '^go: rsc.io/quote@v1.5.2 requires rsc.io/sampler@v1.3.0, not rsc.io/sampler@v1.0.0$'
+
+go list -m all
+stdout 'rsc.io/quote v1.5.1'
+stdout 'rsc.io/sampler v1.3.0'
+
+# go get -u args should limit upgrades
+cp go.mod.empty go.mod
+go get -u rsc.io/quote@v1.4.0 rsc.io/sampler@v1.0.0
+go list -m all
+stdout 'rsc.io/quote v1.4.0'
+stdout 'rsc.io/sampler v1.0.0'
+! stdout golang.org/x/text
+
+# downgrading away quote should also downgrade away latemigrate/v2,
+# since there are no older versions. v2.0.0 is incompatible.
+cp go.mod.orig go.mod
+go list -m -versions example.com/latemigrate/v2
+stdout v2.0.0 # proxy may serve incompatible versions
+go get rsc.io/quote@none
+go list -m all
+! stdout 'example.com/latemigrate/v2'
+
+-- go.mod.orig --
+module x
+require (
+	rsc.io/quote v1.5.1
+	example.com/latemigrate/v2 v2.0.1
+)
+-- go.mod.empty --
+module x
+-- x.go --
+package x