From 381f9c196d19c940a9fc41d36004e984b6231f39 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20G=C3=B6ttgens?= <tgoettgens@gmail.com>
Date: Thu, 16 Jul 2026 21:48:25 +0200
Subject: [PATCH] NodeDB: clear only the slots removeNodeByNum() vacates
 (#11022)

---
 src/mesh/NodeDB.cpp                    | 14 ++++++++---
 test/test_nodedb_blocked/test_main.cpp | 35 ++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/src/mesh/NodeDB.cpp b/src/mesh/NodeDB.cpp
index 9c736312e..f9f04f487 100644
--- a/src/mesh/NodeDB.cpp
+++ b/src/mesh/NodeDB.cpp
@@ -1597,10 +1597,16 @@ void NodeDB::removeNodeByNum(NodeNum nodeNum)
             removed++;
     }
     numMeshNodes -= removed;
-    std::fill(nodeDatabase.nodes.begin() + numMeshNodes, nodeDatabase.nodes.begin() + numMeshNodes + 1,
-              meshtastic_NodeInfoLite());
-    if (removed)
-        eraseNodeSatellites(nodeNum);
+    if (removed) {
+        // Clear exactly the slots compaction vacated. Sizing this from `removed` (rather than a
+        // fixed one) keeps it inside the vector when nothing matched and the store is full.
+        const size_t first = numMeshNodes;
+        const size_t last = std::min(first + removed, nodeDatabase.nodes.size());
+        std::fill(nodeDatabase.nodes.begin() + first, nodeDatabase.nodes.begin() + last, meshtastic_NodeInfoLite());
+    }
+    // Drop the node's satellite stores and warm-tier copy regardless of which tier it lived in, so
+    // an explicit removal fully forgets it.
+    eraseNodeSatellites(nodeNum);
 #if WARM_NODE_COUNT > 0
     // Explicit user removal: don't let the warm tier resurrect the node
     warmStore.remove(nodeNum);
diff --git a/test/test_nodedb_blocked/test_main.cpp b/test/test_nodedb_blocked/test_main.cpp
index 04c1933de..88d7f0259 100644
--- a/test/test_nodedb_blocked/test_main.cpp
+++ b/test/test_nodedb_blocked/test_main.cpp
@@ -225,6 +225,39 @@ static void test_protectedCap_refusesBeyondLimit(void)
     TEST_ASSERT_TRUE(db->setProtectedFlag(already, NODEINFO_BITFIELD_IS_IGNORED_MASK, true));
 }
 
+// removeNodeByNum() compacts survivors down and clears the slots that leaves free. A full
+// store with no matching node frees none, so there is nothing past the last node to clear.
+static void test_removeNodeByNum_absentNodeOnFullDb(void)
+{
+    db->seedSelf();
+    for (int i = 1; i < MAX_NUM_NODES; i++) // fill to MAX_NUM_NODES total (incl. self)
+        db->push(8000 + i, /*last_heard=*/i, false, false, /*withUser=*/true, /*withKey=*/true);
+    TEST_ASSERT_EQUAL_INT(MAX_NUM_NODES, (int)db->getNumMeshNodes());
+
+    db->removeNodeByNum(0xDEADBEEF); // absent; ASan flags a write past the last slot
+
+    TEST_ASSERT_EQUAL_INT(MAX_NUM_NODES, (int)db->getNumMeshNodes()); // nothing removed
+    TEST_ASSERT_NOT_NULL(db->getMeshNode(0x0BADF00D));                // self intact
+    TEST_ASSERT_NOT_NULL(db->getMeshNode(8000 + 1));
+    TEST_ASSERT_NOT_NULL(db->getMeshNode(8000 + MAX_NUM_NODES - 1)); // last slot intact
+}
+
+// Control for the above: a matching node on a full store is still removed, the survivors
+// compact down, and the freed tail slot is cleared.
+static void test_removeNodeByNum_presentNodeOnFullDb(void)
+{
+    db->seedSelf();
+    for (int i = 1; i < MAX_NUM_NODES; i++)
+        db->push(8000 + i, /*last_heard=*/i, false, false, /*withUser=*/true, /*withKey=*/true);
+
+    db->removeNodeByNum(8000 + 5);
+
+    TEST_ASSERT_EQUAL_INT(MAX_NUM_NODES - 1, (int)db->getNumMeshNodes());
+    TEST_ASSERT_NULL(db->getMeshNode(8000 + 5));
+    TEST_ASSERT_NOT_NULL(db->getMeshNode(8000 + 4));
+    TEST_ASSERT_NOT_NULL(db->getMeshNode(8000 + MAX_NUM_NODES - 1)); // survivors kept
+}
+
 NDB_TEST_ENTRY void setup()
 {
     initializeTestEnvironment();
@@ -238,6 +271,8 @@ NDB_TEST_ENTRY void setup()
     RUN_TEST(test_eviction_preservesFavorite);
     RUN_TEST(test_ignored_survivesEvictionAndCleanup);
     RUN_TEST(test_protectedCap_refusesBeyondLimit);
+    RUN_TEST(test_removeNodeByNum_absentNodeOnFullDb);
+    RUN_TEST(test_removeNodeByNum_presentNodeOnFullDb);
     exit(UNITY_END());
 }
 NDB_TEST_ENTRY void loop() {}