Fix segfault when shutting down before fully loading

TheBlueMatt · random-zebra · commit 43cc880a9b28 · 2021-03-02T11:34:08.000+01:00
This was introduced by 3192975. It can be triggered easily when canceling DB upgrade from pre-per-utxo.
diff --git a/src/init.cpp b/src/init.cpp
@@ -263,7 +263,9 @@ void PrepareShutdown()
     }
 
     // FlushStateToDisk generates a SetBestChain callback, which we should avoid missing
-    FlushStateToDisk();
+    if (pcoinsTip != nullptr) {
+        FlushStateToDisk();
+    }
 
     // After there are no more peers/RPC left to give us new data which may generate
     // CValidationInterface callbacks, flush them...

Original file line number	Diff line number	Diff line change
`@@ -263,7 +263,9 @@ void PrepareShutdown()`
`263`	`263`	`}`
`264`	`264`
`265`	`265`	`// FlushStateToDisk generates a SetBestChain callback, which we should avoid missing`
`266`		`- FlushStateToDisk();`
	`266`	`+ if (pcoinsTip != nullptr) {`
	`267`	`+ FlushStateToDisk();`
	`268`	`+ }`
`267`	`269`
`268`	`270`	`// After there are no more peers/RPC left to give us new data which may generate`
`269`	`271`	`// CValidationInterface callbacks, flush them...`