From afebbb876f0a21c827a5153ca907b8a75293ce79 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Tue, 1 Sep 2020 13:46:39 +0200
Subject: [PATCH] nix list-options: Ignore eval errors for now

---
 src/nix/options.cc | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/nix/options.cc b/src/nix/options.cc
index f0baa1e52..486063f01 100644
--- a/src/nix/options.cc
+++ b/src/nix/options.cc
@@ -55,11 +55,17 @@ struct CmdListOptions : InstallableCommand
             auto aValue = aFinal->value->attrs->get(option->name);
             assert(aValue);
 
-            std::ostringstream str;
-            JSONPlaceholder jsonOut(str);
-            PathSet context;
-            printValueAsJSON(*state, true, *aValue->value, jsonOut, context);
-            logger->stdout("  " ANSI_BOLD "Value:" ANSI_NORMAL " %s", str.str());
+            try {
+                std::ostringstream str;
+                JSONPlaceholder jsonOut(str);
+                PathSet context;
+                printValueAsJSON(*state, true, *aValue->value, jsonOut, context);
+                logger->stdout("  " ANSI_BOLD "Value:" ANSI_NORMAL " %s", str.str());
+            } catch (EvalError &) {
+                // FIXME: should ignore "no default" errors, print
+                // other errors.
+                logger->stdout("  " ANSI_BOLD "Value:" ANSI_NORMAL " " ANSI_ITALIC "none" ANSI_NORMAL);
+            }
         }
     }
 };