From c15d29643268057d85d3a1f9900ca9983cb324d6 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Wed, 17 Apr 2024 17:13:22 -0700
Subject: [PATCH] Exercise copyChildrenAndKeyFrom for Node{48,256} to itself

---
 CMakeLists.txt       |  4 ++++
 ConflictSet.cpp      |  6 ++++++
 test_conflict_set.py | 15 +++++++++++++++
 3 files changed, 25 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ce04877..b73142d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -263,6 +263,10 @@ if(BUILD_TESTING)
   # find.
   if(NOT CMAKE_CROSSCOMPILING)
     find_package(Python3 REQUIRED COMPONENTS Interpreter)
+    set_property(
+      DIRECTORY
+      APPEND
+      PROPERTY CMAKE_CONFIGURE_DEPENDS ${CMAKE_SOURCE_DIR}/test_conflict_set.py)
     execute_process(
       COMMAND ${Python3_EXECUTABLE} ${CMAKE_SOURCE_DIR}/test_conflict_set.py
               list OUTPUT_VARIABLE SCRIPT_TESTS)
diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 09bf1b6..068847b 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -1146,8 +1146,14 @@ void freeAndMakeCapacityAtLeast(Node *&self, int capacity,
 // capacity.
 void maybeDecreaseCapacity(Node *&self, NodeAllocators *allocators,
                            ConflictSet::Impl *impl) {
+
   const int maxCapacity =
       (self->numChildren + int(self->entryPresent)) * (self->partialKeyLen + 1);
+#if DEBUG_VERBOSE && !defined(NDEBUG)
+  fprintf(stderr, "maybeDecreaseCapacity: current: %d, max: %d, key: %s\n",
+          self->getCapacity(), maxCapacity,
+          getSearchPathPrintable(self).c_str());
+#endif
   if (self->getCapacity() <= maxCapacity) {
     return;
   }
diff --git a/test_conflict_set.py b/test_conflict_set.py
index 262911e..417dc40 100644
--- a/test_conflict_set.py
+++ b/test_conflict_set.py
@@ -66,6 +66,21 @@ def test_inner_full_words():
         cs.check(read(1, b"\x21", b"\xc2"))
 
 
+def test_decrease_capacity():
+    # make a Node48, then a Node256
+    for count in (17, 49):
+        with DebugConflictSet() as cs:
+            for i in range(count):
+                cs.addWrites(1, write(bytes(([0] * 99) + [i])))
+            # lower its partial key length
+            cs.addWrites(2, write(bytes([0] * 98)))
+            # create work for setOldestVersion
+            for i in range(3, 1000):
+                cs.addWrites(i)
+            # setOldestVersion should decrease the capacity
+            cs.setOldestVersion(1)
+
+
 if __name__ == "__main__":
     # budget "pytest" for ctest integration without pulling in a dependency. You can of course still use pytest in local development.
     import argparse