From 84444c00bf5ad06f8bca4e4cd68e6d227a8efd1e Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Thu, 12 Nov 2026 02:33:43 +0000
Subject: populate flake-input: replace symlinks pointing outside the store

nix-store --add-root only replaces symlinks pointing into the store, so a
symlink pointing elsewhere at the target path, e.g. one a symlink source
left there, made delivering a flake fail.  Populate removes such links.

An edge case switches a symlink source to a flake source.
---
 pkgs/populate/default.nix |  8 +++++++-
 tests/scenarios.nix       | 16 ++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/pkgs/populate/default.nix b/pkgs/populate/default.nix
index 66c88c1..75fbf61 100644
--- a/pkgs/populate/default.nix
+++ b/pkgs/populate/default.nix
@@ -395,7 +395,13 @@ let
       set -efu
       read -r dir
       read -r path
-      if test -e ${quote target.path} && ! test -L ${quote target.path}; then
+      # nix-store --add-root only replaces links into the store.
+      if test -L ${quote target.path}; then
+        case $(readlink ${quote target.path}) in
+          /nix/store/*) ;;
+          *) rm ${quote target.path} ;;
+        esac
+      elif test -e ${quote target.path}; then
         rm -fR ${quote target.path}
       fi
       nix-store --realise "$path" --add-root ${quote target.path} --indirect >/dev/null
diff --git a/tests/scenarios.nix b/tests/scenarios.nix
index 38f8736..9760e54 100644
--- a/tests/scenarios.nix
+++ b/tests/scenarios.nix
@@ -827,6 +827,22 @@ assert !(krops.isLocalTarget (targets.remote "/"));
         }
       ];
     })
+    (s "symlink-to-flake" {
+      phases = [
+        {
+          sources = alt // { x.symlink = "alt"; };
+          check = ''
+            expect_eq link "$(readlink "$T"/x)" alt
+          '';
+        }
+        {
+          sources = alt // { x.flake = { flake = "/fixtures/top"; inherit fetchOnTarget; }; };
+          check = checkFlake { attr = "msg"; expected = "top:dep+inner,sub"; } + ''
+            test -e "$T"/alt/flake.nix || fail "alt changed"
+          '';
+        }
+      ];
+    })
   ] ++ lib.optional (targetKind == "local")
     # The target has the path the input is locked to.
     (s "uselocal" {
-- 
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