Merge pull request tweag#20 from tweag/fd/debug-output

Print stdout and stderr when nix-build fails.
ryanrasti · Jul 2, 2018 · c3a0408 · c3a0408
2 parents 20a78f7 + d9df5c8
commit c3a0408
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/nixpkgs/nixpkgs.bzl b/nixpkgs/nixpkgs.bzl
@@ -86,7 +86,9 @@ Set which Nixpkgs to use explicitly using 'repository' or 'path' attributes.
   if res.return_code == 0:
     output_path = res.stdout.splitlines()[-1]
   else:
-    fail("Cannot build Nix attribute %s." % ctx.attr.name)
+    fail("Cannot build Nix attribute %s.\nstdout:\n%s\n\nstderr:\n%s\n" %
+            (ctx.attr.name, res.stdout, res.stderr)
+        )
 
   # Build a forest of symlinks (like new_local_package() does) to the
   # Nix store.