Don't substitute when setting up the default profile / self-testing (#…

…1101)

* setup_default_profile: don't substitute

We already have everything we need, so substitution is not necessary
(and makes it slower in our VM tests without networking).

* self_test: don't substitute

This should always be a local build.

src/action/base/setup_default_profile.rs

@@ -118,6 +118,7 @@ impl Action for SetupDefaultProfile {
         execute_command(
             Command::new(nix_pkg.join("bin/nix-env"))
                 .process_group(0)
+                .args(["--option", "substitute", "false"])
                 .arg("-i")
                 .arg(&nix_pkg)
                 .stdin(std::process::Stdio::null())
@@ -138,6 +139,7 @@ impl Action for SetupDefaultProfile {
         execute_command(
             Command::new(nix_pkg.join("bin/nix-env"))
                 .process_group(0)
+                .args(["--option", "substitute", "false"])
                 .arg("-i")
                 .arg(&nss_ca_cert_pkg)
                 .stdin(std::process::Stdio::null())

src/self_test.rs

@@ -105,7 +105,7 @@ impl Shell {
             .as_millis();
 
         command.arg(format!(
-            r#"nix build --no-link --expr 'derivation {{ name = "self-test-{executable}-{timestamp_millis}"; system = "{SYSTEM}"; builder = "/bin/sh"; args = ["-c" "echo hello > \$out"]; }}'"#
+            r#"nix build --option substitute false --no-link --expr 'derivation {{ name = "self-test-{executable}-{timestamp_millis}"; system = "{SYSTEM}"; builder = "/bin/sh"; args = ["-c" "echo hello > \$out"]; }}'"#
         ));
         let command_str = format!("{:?}", command.as_std());