From acf178575cf2f6238b8565594958141b2fb007a1 Mon Sep 17 00:00:00 2001
From: devil <europedreadlydevil@gmail.com>
Date: Wed, 30 Sep 2026 11:20:28 +0000
Subject: [PATCH 1/3] #1176: refuse to delete from a fact that is no longer in
 the factbase

---
 lib/fbe/delete.rb     | 1 +
 lib/fbe/delete_one.rb | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/fbe/delete.rb b/lib/fbe/delete.rb
index ee21bf31..23918b4a 100644
--- a/lib/fbe/delete.rb
+++ b/lib/fbe/delete.rb
@@ -34,6 +34,7 @@ def Fbe.delete(fact, *props, fb: Fbe.fb, id: '_id') # rubocop:disable Metrics/Cy
   end
   fb.txn do |fbt|
     deleted = fbt.query("(eq #{id} #{i})").delete!
+    raise(Fbe::Error, "No facts by #{id} = #{i}") if deleted.zero?
     raise(Fbe::Error, "#{deleted} facts share #{id} = #{i}, cannot delete one of them") if deleted > 1
     c = fbt.insert
     f = c
diff --git a/lib/fbe/delete_one.rb b/lib/fbe/delete_one.rb
index 7e41eefc..f2a0e603 100644
--- a/lib/fbe/delete_one.rb
+++ b/lib/fbe/delete_one.rb
@@ -36,7 +36,7 @@ def Fbe.delete_one(fact, prop, value, fb: Fbe.fb, id: '_id')
   before[prop] = nv
   before.delete(prop) if nv.empty?
   fb.txn do |fbt|
-    fbt.query("(eq #{id} #{i})").delete!
+    raise(Fbe::Error, "No facts by #{id} = #{i}") if fbt.query("(eq #{id} #{i})").delete!.zero?
     c = fbt.insert
     f = c
     while f.instance_variable_defined?(:@fact) || f.instance_variable_defined?(:@origin)

From 922939fa82ea02752ef556a47f569d7c55e10fa0 Mon Sep 17 00:00:00 2001
From: devil <europedreadlydevil@gmail.com>
Date: Wed, 30 Sep 2026 11:21:05 +0000
Subject: [PATCH 2/3] #1176: test that a removed fact is not brought back

---
 test/fbe/test_delete.rb     | 11 +++++++++++
 test/fbe/test_delete_one.rb | 11 +++++++++++
 2 files changed, 22 insertions(+)

diff --git a/test/fbe/test_delete.rb b/test/fbe/test_delete.rb
index a46409e8..384c63d0 100644
--- a/test/fbe/test_delete.rb
+++ b/test/fbe/test_delete.rb
@@ -15,6 +15,17 @@
 # Copyright:: Copyright (c) 2024-2026 Zerocracy
 # License:: MIT
 class TestDelete < Fbe::Test
+  def test_refuses_to_bring_back_a_removed_fact
+    fb = Factbase.new
+    f = fb.insert
+    f._id = 1
+    f.k = 1
+    f.t = 5
+    fb.query('(eq _id 1)').delete!
+    assert_raises(Fbe::Error) { Fbe.delete(f, 't', fb:) }
+    assert_equal(0, fb.size)
+  end
+
   def test_deletes_one_property
     fb = Factbase.new
     f = fb.insert
diff --git a/test/fbe/test_delete_one.rb b/test/fbe/test_delete_one.rb
index d3e421ce..9f3b28e6 100644
--- a/test/fbe/test_delete_one.rb
+++ b/test/fbe/test_delete_one.rb
@@ -15,6 +15,17 @@
 # Copyright:: Copyright (c) 2024-2026 Zerocracy
 # License:: MIT
 class TestDeleteOne < Fbe::Test
+  def test_refuses_to_bring_back_a_removed_fact
+    fb = Factbase.new
+    f = fb.insert
+    f._id = 1
+    f.k = 1
+    f.t = 5
+    fb.query('(eq _id 1)').delete!
+    assert_raises(Fbe::Error) { Fbe.delete_one(f, 't', 5, fb:) }
+    assert_equal(0, fb.size)
+  end
+
   def test_deletes_one_value
     fb = Factbase.new
     f = fb.insert

From 86c6cad34bee22d2d1897ed410f9e0610cf3a575 Mon Sep 17 00:00:00 2001
From: devil <europedreadlydevil@gmail.com>
Date: Wed, 30 Sep 2026 11:21:26 +0000
Subject: [PATCH 3/3] #1176: keep delete_one within the complexity limits of
 rubocop

---
 lib/fbe/delete_one.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/fbe/delete_one.rb b/lib/fbe/delete_one.rb
index f2a0e603..90ce780f 100644
--- a/lib/fbe/delete_one.rb
+++ b/lib/fbe/delete_one.rb
@@ -18,7 +18,7 @@
 # @param [Factbase] fb The factbase to use (defaults to Fbe.fb)
 # @param [String] id The property name used as unique identifier (defaults to '_id')
 # @return [nil] Nothing
-def Fbe.delete_one(fact, prop, value, fb: Fbe.fb, id: '_id')
+def Fbe.delete_one(fact, prop, value, fb: Fbe.fb, id: '_id') # rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
   raise(Fbe::Error, 'The fact is nil') if fact.nil?
   prop = prop.to_s
   i = fact[id]