From 52b7357a1b2ea287448b4035e14d92a2b29711fb Mon Sep 17 00:00:00 2001
From: Matthieu Coudron <886074+teto@users.noreply.github.com>
Date: Sun, 27 Aug 2023 00:29:05 +0200
Subject: [PATCH] nix flake show: name attribute that must be a derivation
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I would run `nix flake show` on a flake than hit:

===
        ├───ihaskell: package 'ihaskell-wrapper'
        ├───ihaskell-96: package 'ihaskell-wrapper'
        ├───ihaskell-96-dev: package 'ghc-shell-for-ihaskell-0.10.4.0'
error: expected a derivation
===
and it is not obvious what package is the culprit here since nix stops
rightaway.
---
 src/nix/flake.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/nix/flake.cc b/src/nix/flake.cc
index 3d174dc53..cef674eb5 100644
--- a/src/nix/flake.cc
+++ b/src/nix/flake.cc
@@ -1332,8 +1332,10 @@ struct CmdFlakeShow : FlakeCommand, MixJSON
                         try {
                             if (visitor.isDerivation())
                                 showDerivation();
-                            else
-                                throw Error("expected a derivation");
+                            else {
+                                auto name = visitor.getAttrPathStr(state->sName);
+                                logger->warn(fmt("%s must be a derivation", name));
+                            }
                         } catch (IFDError & e) {
                             if (!json) {
                                 logger->cout(fmt("%s " ANSI_WARNING "omitted due to use of import from derivation" ANSI_NORMAL, headerPrefix));