cmd/go: add move test for goroot

This  an end-to-end test that sets GOROOT to a symlink
to the distribution, approximating copying it to a new
location, and checks that packages in the standard library
are not stale, as they would be if paths were embedded
in artifacts.

For #47257

Change-Id: I4ed04df36656ad946a2f6f5ce3194e76e06372e3
Reviewed-on: https://go-review.googlesource.com/c/go/+/445358
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>

diff --git a/src/cmd/go/testdata/script/install_move_not_stale.txt b/src/cmd/go/testdata/script/install_move_not_stale.txt
new file mode 100644 (file)
index 0000000..de191cf
--- /dev/null
+++ b/src/cmd/go/testdata/script/install_move_not_stale.txt
@@ -0,0 +1,26 @@
+# Check to see that the distribution is not stale
+# even when it's been moved to a different directory.
+# Simulate that by creating a symlink to the tree.
+
+# We use net instead of std because stale std has
+# the behavior of checking that all std targets
+# are stale rather than any of them.
+
+[!symlink] skip
+[short] skip
+
+go build net
+! stale net
+
+symlink new -> $GOROOT
+env OLDGOROOT=$GOROOT
+env GOROOT=$WORK${/}gopath${/}src${/}new
+go env GOROOT
+stdout $WORK[\\/]gopath[\\/]src[\\/]new
+cd new
+! stale net
+
+# Add a control case to check that std is
+# stale with an empty cache
+env GOCACHE=$WORK${/}gopath${/}cache
+stale net