From a540a112bbccd1b92848de3d89d5ecef7fc07dec Mon Sep 17 00:00:00 2001
From: dfahlander <david.fahlander@gmail.com>
Date: Fri, 16 Oct 2020 11:08:38 +0200
Subject: [PATCH 1/2] Repro of #1145

---
 test/tests-upgrading.js | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/test/tests-upgrading.js b/test/tests-upgrading.js
index 4a6c1ac13..5cb4f7b34 100644
--- a/test/tests-upgrading.js
+++ b/test/tests-upgrading.js
@@ -793,3 +793,36 @@ promisedTest("Issue #959 - Should migrate successfully with an explicit unique m
         equal(result2.name, "Bar", "The expected friends was returned");
     }
 );
+
+
+promisedTest(
+  "Issue 1145 - Regression: SchemaError during version upgrade",
+  async () => {
+    const DBNAME = "issue1145";
+    await Dexie.delete(DBNAME);
+    const db = new Dexie(DBNAME);
+    db.version(1).stores({ Y: "id" });
+    await db.open();
+    await db.close();
+    db.version(2).upgrade((trans) => {
+      ok(true, "Starting version 2 upgrade.");
+      return trans.Y.count();
+    });
+    db.version(3).stores({
+      Y: "id,X",
+    });
+    db.version(4).upgrade((trans) => {
+      ok(true, "Starting version 4 upgrade.");
+      return trans.Y.where("X").equals("value").toArray();
+    });
+
+    try {
+      await db.open();
+      ok(true, "Open successful");
+    } catch (e) {
+      ok(false, "Open Failed:: " + e);
+    } finally {
+      await db.delete();
+    }
+  }
+);

From 96f8d2c88b5bc1de6c613d4a2fb7c78b4fee6887 Mon Sep 17 00:00:00 2001
From: dfahlander <david.fahlander@gmail.com>
Date: Fri, 16 Oct 2020 11:49:51 +0200
Subject: [PATCH 2/2] Resolve #1145

---
 src/classes/version/schema-helpers.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/classes/version/schema-helpers.ts b/src/classes/version/schema-helpers.ts
index 142db7924..e3defff47 100644
--- a/src/classes/version/schema-helpers.ts
+++ b/src/classes/version/schema-helpers.ts
@@ -127,6 +127,7 @@ export function updateTablesAndIndexes(
       if (contentUpgrade && version._cfg.version > oldVersion) {
         // Update db.core with new tables and indexes:
         generateMiddlewareStacks(db, idbUpgradeTrans);
+        trans._memoizedTables = {}; // Invalidate memoization as transaction shape may change between versions.
 
         anyContentUpgraderHasRun = true;