From d34ad9f8359d5eea2c46dde0be3c0cafd5263529 Mon Sep 17 00:00:00 2001
From: "Brian S. O'Neill" <bronee@gmail.com>
Date: Tue, 12 Nov 2024 07:17:38 -0800
Subject: [PATCH] Cannot rebuild a replicated database. This feature must be
 integrated into the restore phase.

---
 src/main/java/org/cojen/tupl/Database.java       | 2 +-
 src/main/java/org/cojen/tupl/core/Launcher.java  | 4 ++++
 src/main/java/org/cojen/tupl/core/Rebuilder.java | 6 ++++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/cojen/tupl/Database.java b/src/main/java/org/cojen/tupl/Database.java
index acbaf840a..4d5fe7beb 100644
--- a/src/main/java/org/cojen/tupl/Database.java
+++ b/src/main/java/org/cojen/tupl/Database.java
@@ -126,7 +126,7 @@ public static Database connect(SocketAddress addr, SSLContext context, long... t
      * @param numThreads pass 0 for default, or if negative, the actual number will be {@code
      * (-numThreads * availableProcessors)}.
      * @return the newly built database
-     * @throws IllegalStateException if the new database already exists
+     * @throws IllegalStateException if the new database already exists or if either is replicated
      */
     public static Database rebuild(DatabaseConfig oldConfig, DatabaseConfig newConfig,
                                    int numThreads)
diff --git a/src/main/java/org/cojen/tupl/core/Launcher.java b/src/main/java/org/cojen/tupl/core/Launcher.java
index 63f2a0a21..0b20ce04b 100644
--- a/src/main/java/org/cojen/tupl/core/Launcher.java
+++ b/src/main/java/org/cojen/tupl/core/Launcher.java
@@ -400,6 +400,10 @@ EnumSet<OpenOption> createOpenOptions() {
         return options;
     }
 
+    boolean isReplicated() {
+        return mRepl != null || mReplConfig != null;
+    }
+
     /**
      * @return true if mRepl was assigned a new replicator
      */
diff --git a/src/main/java/org/cojen/tupl/core/Rebuilder.java b/src/main/java/org/cojen/tupl/core/Rebuilder.java
index 827ad972a..b547144ba 100644
--- a/src/main/java/org/cojen/tupl/core/Rebuilder.java
+++ b/src/main/java/org/cojen/tupl/core/Rebuilder.java
@@ -60,6 +60,12 @@ public CoreDatabase run() throws IOException {
     private void doRun() throws IOException {
         // Prepare configuration and perform basic configuration checks.
 
+        if (mOldLauncher.isReplicated() || mNewLauncher.isReplicated()) {
+            // Both databases must not be concurrently modified by any other threads. This is
+            // always possible with a replicated database.
+            throw new IllegalStateException("Cannot rebuild a replicated database");
+        }
+
         // Page access mode must be consistent in order for the parallelCopy method to work.
         if (mNewLauncher.mDirectPageAccess == null) {
             mNewLauncher.mDirectPageAccess = mOldLauncher.mDirectPageAccess;