environment: Provide /etc/hosts in containers without '--network'.

Fixes <https://bugs.gnu.org/43762>.

* guix/scripts/environment.scm (launch-environment/container): Create
/etc/hosts when NETWORK? is false.
* tests/guix-environment-container.sh: Add "localhost" resolution test.

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/guix-environment-container.sh b/tests/guix-environment-container.sh
index 040f32cce92..3674aa60269 100644
--- a/tests/guix-environment-container.sh
+++ b/tests/guix-environment-container.sh
@@ -44,6 +44,10 @@ else
     test $? = 42
 fi
 
+# Make sure "localhost" resolves.
+guix environment --container --ad-hoc --bootstrap guile-bootstrap \
+     -- guile -c '(exit (pair? (getaddrinfo "localhost" "80")))'
+
 # Make sure '--preserve' is honored.
 result="`FOOBAR=42; export FOOBAR; guix environment -C --ad-hoc --bootstrap \
    guile-bootstrap -E ^FOO -- guile -c '(display (getenv \"FOOBAR\"))'`"