From 1516bb18b070d6fbc0388791edb8cb1040ad0d6e Mon Sep 17 00:00:00 2001
From: Christopher Lam <christopher.lck@gmail.com>
Date: Thu, 2 Dec 2021 22:12:29 +0800
Subject: [PATCH] [gnc-features.cpp] backport gnc_features_set_unused from
 master

---
 libgnucash/engine/gnc-features.cpp | 17 +++++++++++++++++
 libgnucash/engine/gnc-features.h   |  7 +++++++
 2 files changed, 24 insertions(+)

diff --git a/libgnucash/engine/gnc-features.cpp b/libgnucash/engine/gnc-features.cpp
index 5e2823a3c3..07d3e59fe2 100644
--- a/libgnucash/engine/gnc-features.cpp
+++ b/libgnucash/engine/gnc-features.cpp
@@ -91,6 +91,23 @@ void gnc_features_set_used (QofBook *book, const gchar *feature)
     qof_book_set_feature (book, feature, iter->second.c_str());
 }
 
+
+void gnc_features_set_unused (QofBook *book, const gchar *feature)
+{
+    g_return_if_fail (book);
+    g_return_if_fail (feature);
+
+    /* Can't set an unknown feature */
+    auto iter = features_table.find (feature);
+    if (iter == features_table.end ())
+    {
+        PWARN("Tried to set unknown feature as unused.");
+        return;
+    }
+
+    qof_book_unset_feature (book, feature);
+}
+
 gboolean gnc_features_check_used (QofBook *book, const gchar * feature)
 {
     return qof_book_test_feature (book, feature);
diff --git a/libgnucash/engine/gnc-features.h b/libgnucash/engine/gnc-features.h
index 030c02531e..b5960ac7ad 100644
--- a/libgnucash/engine/gnc-features.h
+++ b/libgnucash/engine/gnc-features.h
@@ -67,6 +67,13 @@ extern "C" {
  */
 gchar *gnc_features_test_unknown (QofBook *book);
 
+/**
+ * Indicate that the current book does not use the given feature. This
+ * will allow older versions of GnuCash that don't support this
+ * feature to load this book.
+ */
+void gnc_features_set_unused (QofBook *book, const gchar *feature);
+
 /**
  * Indicate that the current book uses the given feature. This will prevent
  * older versions of GnuCash that don't support this feature to refuse to load