copy-tarballs.pl: Revive extracting all tarballs from release.nix

maintainers/scripts/all-tarballs.nix

@@ -0,0 +1,18 @@
+/* Helper expression for copy-tarballs. This returns (nearly) all
+   tarballs used the free packages in Nixpkgs.
+
+   Typical usage:
+
+   $ copy-tarballs.pl --expr 'import <nixpkgs/maintainers/scripts/all-tarballs.nix>'
+*/
+
+removeAttrs (import ../../pkgs/top-level/release.nix
+  { # Don't apply ‘hydraJob’ to jobs, because then we can't get to the
+    # dependency graph.
+    scrubJobs = false;
+    # No need to evaluate on i686.
+    supportedSystems = [ "x86_64-linux" ];
+  })
+  [ # Remove jobs whose evaluation depends on a writable Nix store.
+    "tarball" "unstable"
+  ]

maintainers/scripts/copy-tarballs.pl

@@ -93,7 +93,7 @@ elsif ($op eq "--expr") {
 
     # Evaluate find-tarballs.nix.
     my $expr = $ARGV[0] // die "$0: --expr requires a Nix expression\n";
-    my $pid = open(JSON, "-|", "nix-instantiate", "--eval-only", "--json", "--strict",
+    my $pid = open(JSON, "-|", "nix-instantiate", "--eval", "--json", "--strict",
                    "<nixpkgs/maintainers/scripts/find-tarballs.nix>",
                    "--arg", "expr", $expr);
     my $stdout = <JSON>;
@@ -113,6 +113,11 @@ elsif ($op eq "--expr") {
         my $algo = $fetch->{type};
         my $hash = $fetch->{hash};
 
+        if (defined $ENV{DEBUG}) {
+            print "$url $algo $hash\n";
+            next;
+        }
+
         if ($url !~ /^http:/ && $url !~ /^https:/ && $url !~ /^ftp:/ && $url !~ /^mirror:/) {
             print STDERR "skipping $url (unsupported scheme)\n";
             next;

maintainers/scripts/find-tarballs.nix

@@ -1,10 +1,9 @@
-# This expression returns a list of all fetchurl calls used by all
-# packages reachable from release.nix.
+# This expression returns a list of all fetchurl calls used by ‘expr’.
 
 with import ../.. { };
 with lib;
 
-{ expr ? removeAttrs (import ../../pkgs/top-level/release.nix { }) [ "tarball" "unstable" ] }:
+{ expr }:
 
 let