Index: src/main.c
==================================================================
--- src/main.c
+++ src/main.c
@@ -2161,20 +2161,20 @@
   /* Also add a UTF-8 case-insensitive collation sequence. */
   createCollation(db, "NOCASE", SQLITE_UTF8, SQLITE_COLL_NOCASE, 0,
                   nocaseCollatingFunc, 0);
 
   /* Parse the filename/URI argument. */
+  db->openFlags = flags;
   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
   if( rc!=SQLITE_OK ){
     if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
     sqlite3Error(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
     sqlite3_free(zErrMsg);
     goto opendb_out;
   }
 
   /* Open the backend database driver */
-  db->openFlags = flags;
   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
                         flags | SQLITE_OPEN_MAIN_DB);
   if( rc!=SQLITE_OK ){
     if( rc==SQLITE_IOERR_NOMEM ){
       rc = SQLITE_NOMEM;

Index: test/uri.test
==================================================================
--- test/uri.test
+++ test/uri.test
@@ -19,10 +19,11 @@
 #   2.*: That URI options (query parameters) are correctly extracted from URIs.
 #   3.*: That specifying an unknown VFS causes an error.
 #   4.*: Tests for specifying other options (other than "vfs").
 #   5.*: Test using a different VFS with an attached database.
 #   6.*: Test that authorities other than "" and localhost cause errors.
+#   7.*: Test that a read-write db can be attached to a read-only connection.
 #
 
 set testprefix uri
 db close
 sqlite3_shutdown
@@ -280,7 +281,29 @@
     sqlite3_errmsg $DB
   } $res
   catch { sqlite3_close $DB }
 }
 
-finish_test
+forcedelete test.db test.db2
+do_test 7.1 {
+  sqlite3 db test.db
+  execsql {
+    CREATE TABLE t1(a, b);
+    INSERT INTO t1 VALUES(1, 2);
+    ATTACH 'test.db2' AS aux;
+    CREATE TABLE aux.t2(a, b);
+    INSERT INTO t1 VALUES('a', 'b');
+  }
+  db close
+} {}
+do_test 7.2 {
+  sqlite3 db file:test.db?mode=ro
+  execsql { ATTACH 'file:test.db2?mode=rw' AS aux }
+} {}
+do_execsql_test  7.3 { 
+  INSERT INTO t2 VALUES('c', 'd') 
+} {}
+do_catchsql_test 7.4 { 
+  INSERT INTO t1 VALUES(3, 4) 
+} {1 {attempt to write a readonly database}}
 
+finish_test