From 89c6aae53a39193454eee4d049d332a91f2306f0 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Sun, 19 May 2024 20:08:27 -0700
Subject: [PATCH] Fix bugs found through fuzzing

---
 Facade.h         | 12 ++++++------
 VersionedMap.cpp |  9 ++++++++-
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/Facade.h b/Facade.h
index b13b8e1..02b4bdb 100644
--- a/Facade.h
+++ b/Facade.h
@@ -29,12 +29,6 @@ struct Facade {
       const int64_t v[] = {version, version};
       facade->versioned.firstGeq(key, v, versionedIter, 2);
 
-      if (versionedIter[0] == versionedIter[1]) {
-        // No mutations intersect [begin, end)
-        facade->unversionedRead(begin, end, limit, reverse, result);
-        return result;
-      }
-
       // Make sure versionedIter[1] param1 is >= `end`
       if (versionedIter[1] != facade->versioned.end(version)) {
         auto m = *versionedIter[1];
@@ -43,6 +37,12 @@ struct Facade {
         }
       }
 
+      if (versionedIter[0] == versionedIter[1]) {
+        // No mutations intersect [begin, end)
+        facade->unversionedRead(begin, end, limit, reverse, result);
+        return result;
+      }
+
       static const uint8_t zero_[] = {0};
       static const String zero{zero_, 1};
 
diff --git a/VersionedMap.cpp b/VersionedMap.cpp
index 25eae08..fb2132f 100644
--- a/VersionedMap.cpp
+++ b/VersionedMap.cpp
@@ -653,7 +653,14 @@ struct __attribute__((__visibility__("hidden"))) VersionedMap::Impl {
       rangeVersion = latestVersion;
       if (inserted) {
         val = {nullptr, -1}; // Sentinel for "no point mutation here"
-        pointVersion = -1;   // Sentinel for "no point mutation here"
+        Finger copy;
+        finger.copyTo(copy);
+        move<std::memory_order_relaxed>(copy, latestVersion, true);
+        if (copy.searchPathSize() == 0) {
+          pointVersion = -1; // Sentinel for "no mutation ending here"
+        } else {
+          pointVersion = mm.base[copy.backNode()].entry->rangeVersion;
+        }
       } else {
         auto *entry = mm.base[finger.backNode()].entry;
         val = {entry->getVal(), entry->valLen};