From a0635a80b2c3bc89baffd64b1d91d7efa2d2fd3a Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Sun, 14 Jul 2024 14:28:21 +0200
Subject: [PATCH] printAttrs: Force item before determining whether to print
 multi-line

---
 src/libexpr/print.cc                                   | 6 ++++++
 tests/functional/repl/pretty-print-idempotent.expected | 4 +---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/libexpr/print.cc b/src/libexpr/print.cc
index 2f377e588..6167abee8 100644
--- a/src/libexpr/print.cc
+++ b/src/libexpr/print.cc
@@ -299,6 +299,9 @@ private:
             output << ANSI_NORMAL;
     }
 
+    /**
+     * @note This may force items.
+     */
     bool shouldPrettyPrintAttrs(AttrVec & v)
     {
         if (!options.shouldPrettyPrint() || v.empty()) {
@@ -315,6 +318,9 @@ private:
             return true;
         }
 
+        // It is ok to force the item(s) here, because they will be printed anyway.
+        state.forceValue(*item, item->determinePos(noPos));
+
         // Pretty-print single-item attrsets only if they contain nested
         // structures.
         auto itemType = item->type();
diff --git a/tests/functional/repl/pretty-print-idempotent.expected b/tests/functional/repl/pretty-print-idempotent.expected
index e74239564..949d7a0e6 100644
--- a/tests/functional/repl/pretty-print-idempotent.expected
+++ b/tests/functional/repl/pretty-print-idempotent.expected
@@ -2,9 +2,7 @@ Nix <nix version>
 Type :? for help.
 Added <number omitted> variables.
 
-{
-  homepage = "https://example.com";
-}
+{ homepage = "https://example.com"; }
 
 { homepage = "https://example.com"; }