From 4910d74086a85876e093136a0e8ebc547b467af7 Mon Sep 17 00:00:00 2001
From: Rebecca Turner <rbt@sent.as>
Date: Fri, 8 Mar 2024 21:43:54 -0800
Subject: [PATCH 1/2] Print derivation paths in `nix eval`

`nix eval` forces values and prints derivations as attribute sets, so
commands that print derivations (e.g. `nix eval nixpkgs#bash`) will
infinitely loop and segfault.

Printing derivations as `.drv` paths makes `nix eval` complete as
expected. Further work is needed, but this is better than a segfault.
---
 src/nix/eval.cc | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/nix/eval.cc b/src/nix/eval.cc
index 2044c8c2b..088be3b17 100644
--- a/src/nix/eval.cc
+++ b/src/nix/eval.cc
@@ -120,8 +120,17 @@ struct CmdEval : MixJSON, InstallableValueCommand, MixReadOnlyOption
         }
 
         else {
-            state->forceValueDeep(*v);
-            logger->cout("%s", ValuePrinter(*state, *v, PrintOptions { .force = true }));
+            logger->cout(
+                "%s",
+                ValuePrinter(
+                    *state,
+                    *v,
+                    PrintOptions {
+                        .force = true,
+                        .derivationPaths = true
+                    }
+                )
+            );
         }
     }
 };

From 7f45b1c8d8caf4beeb68c981ae813d6251a7ee63 Mon Sep 17 00:00:00 2001
From: Rebecca Turner <rbt@sent.as>
Date: Mon, 11 Mar 2024 09:21:24 -0700
Subject: [PATCH 2/2] Add release note

---
 doc/manual/rl-next/nix-eval-derivations.md | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 doc/manual/rl-next/nix-eval-derivations.md

diff --git a/doc/manual/rl-next/nix-eval-derivations.md b/doc/manual/rl-next/nix-eval-derivations.md
new file mode 100644
index 000000000..ed0a73384
--- /dev/null
+++ b/doc/manual/rl-next/nix-eval-derivations.md
@@ -0,0 +1,13 @@
+---
+synopsis: "`nix eval` prints derivations as `.drv` paths"
+prs: 10200
+---
+
+`nix eval` will now print derivations as their `.drv` paths, rather than as
+attribute sets. This makes commands like `nix eval nixpkgs#bash` terminate
+instead of infinitely looping into recursive self-referential attributes:
+
+```ShellSession
+$ nix eval nixpkgs#bash
+«derivation /nix/store/m32cbgbd598f4w299g0hwyv7gbw6rqcg-bash-5.2p26.drv»
+```