Avoid writing frames with no checksums into the wal file if a savepoint is rolled back after dirty pages have already been spilled into the wal file. Possible fix for [forum:/forumpost/b490f726db | forum post b490f726db].

FossilOrigin-Name: 3a3269fe8e925a522d5df9f011220a842fb15a9f56e785884e32d2e15abda5bb

manifest

@@ -1,5 +1,5 @@
-C Fix\san\sissue\sgoing\sback\sto\sversion\s3.39.0\swith\stransitive\sIS\sconstraints\nin\squeries\sthat\smake\suse\sof\sRIGHT\sJOIN.\s\sProblem\sreported\sby\n[forum:/forumpost/68f29a2005|forum\spost\s68f29a2005].
+C Avoid\swriting\sframes\swith\sno\schecksums\sinto\sthe\swal\sfile\sif\sa\ssavepoint\sis\srolled\sback\safter\sdirty\spages\shave\salready\sbeen\sspilled\sinto\sthe\swal\sfile.\sPossible\sfix\sfor\s[forum:/forumpost/b490f726db\s|\sforum\spost\sb490f726db].
-D 2025-06-16T17:36:11.335
+D 2025-06-17T11:36:39.164
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -864,7 +864,7 @@ F src/vdbetrace.c fe0bc29ebd4e02c8bc5c1945f1d2e6be5927ec12c06d89b03ef2a4def34bf8
 F src/vdbevtab.c fc46b9cbd759dc013f0b3724549cc0d71379183c667df3a5988f7e2f1bd485f3
 F src/vtab.c 828221bdbeaaa6d62126ee6d07fd4ec0d09dcaea846f87ad01944d8b7e548859
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
-F src/wal.c b0f848cfba8dd057f77073493cdd542f9125b4cf87941f53e9d0db21604155c8
+F src/wal.c 20be6f0a25a80b7897cf2a5369bfd37ef198e6f0b6cdef16d83eee856056b159
 F src/wal.h ba252daaa94f889f4b2c17c027e823d9be47ce39da1d3799886bbd51f0490452
 F src/walker.c d5006d6b005e4ea7302ad390957a8d41ed83faa177e412f89bc5600a7462a014
 F src/where.c a99fa3061a0155d2cb0e2c91df76dbf834750272a8d79ec5e2dce3ed4e6abad6
@@ -2014,7 +2014,7 @@ F test/wal_common.tcl 204d1721ac13c5e0c7fae6380315b5ab7f4e8423f580d826c5e9df1995
 F test/walbak.test 018d4e5a3d45c6298d11b99f09a8ef6876527946
 F test/walbig.test f437473a16cfb314867c6b5d1dbcd519e73e3434
 F test/walblock.test 6bb472e82730e7e4e81395e907a01d8cfc2bd9e1f01f8a9184ca572e2955a4bf
-F test/walcksum.test ba02b4fe6d22cb42e57a323003cbae62f77a740983e1355b2b520e019ae261c7
+F test/walcksum.test 158598ad68d9ea84e67eabbbb9043f6cb9304d58fae53929fea628333ddaf4c4
 F test/walcrash.test 21038858cc552077b0522f50b0fa87e38139306a
 F test/walcrash2.test a0edab4e5390f03b99a790de89aad15d6ec70b36
 F test/walcrash3.test e426aa58122d20f2b9fbe9a507f9eb8cab85b8af
@@ -2208,8 +2208,11 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 1ad0169b022b280bcaaf94a7fa231591be96b514230ab5c98fbf15cd7df842dd
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 94b53c20e9bc8687c44272419aa7a93076eebdeae9a4f50b95b96a49993f9c0d
+P 9441fff52cc4e19c44df1a77ffe474f409d519b270c7166ce17f99e6ea48fc1e
-R 9792eecd1b6591bc063a59b87986da50
+R 93b4b43fd06afdd1b9668d9d2f8541cf
-U drh
+T *branch * forum-b490f726db-fix
-Z 7fae65e62acbc3e4e5d9b145df615a7d
+T *sym-forum-b490f726db-fix *
+T -sym-trunk *
+U dan
+Z d6bf754839869813fcea9434feef2ab0
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-9441fff52cc4e19c44df1a77ffe474f409d519b270c7166ce17f99e6ea48fc1e
+3a3269fe8e925a522d5df9f011220a842fb15a9f56e785884e32d2e15abda5bb

src/wal.c

@@ -3781,6 +3781,7 @@ int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
       if( iMax!=pWal->hdr.mxFrame ) walCleanupHash(pWal);
     }
     SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+    pWal->iReCksum = 0;
   }
   return rc;
 }
@@ -3828,6 +3829,9 @@ int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData){
       walCleanupHash(pWal);
     }
     SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+    if( pWal->iReCksum>pWal->hdr.mxFrame ){
+      pWal->iReCksum = 0;
+    }
   }
 
   return rc;

test/walcksum.test

@@ -16,6 +16,7 @@ source $testdir/lock_common.tcl
 source $testdir/wal_common.tcl
 
 ifcapable !wal {finish_test ; return }
+set testprefix walcksum
 
 # Read and return the contents of file $filename. Treat the content as
 # binary data.
@@ -331,5 +332,149 @@ do_test walcksum-2.1 {
 catch { db close }
 catch { db2 close }
 
+#-------------------------------------------------------------------------
+# Test cases based on the bug reported at:
+# 
+#    <https://sqlite.org/forum/forumpost/b490f726db>
+#
+reset_db
+
+do_execsql_test 3.0 {
+  PRAGMA synchronous = NORMAL;
+  PRAGMA journal_mode = WAL;
+  PRAGMA cache_size = 1;
+
+  CREATE TABLE t1 (i INTEGER PRIMARY KEY, b BLOB, t TEXT);
+  PRAGMA wal_checkpoint;
+  INSERT INTO t1 VALUES(1, randomblob(2048), 'one');
+} {wal 0 2 2}
+
+do_execsql_test 3.1 {
+  BEGIN;
+    INSERT INTO t1 VALUES(2, randomblob(2048), 'two');
+    SAVEPOINT one;
+    INSERT INTO t1 VALUES(3, randomblob(2048), 'three');
+    INSERT INTO t1 VALUES(4, randomblob(2048), 'four');
+    INSERT INTO t1 VALUES(5, randomblob(2048), 'five');
+    INSERT INTO t1 VALUES(6, randomblob(2048), 'six');
+    INSERT INTO t1 VALUES(7, randomblob(2048), 'seven');
+
+    UPDATE t1 SET b=randomblob(2048) WHERE i=5;
+    UPDATE t1 SET b=randomblob(2048) WHERE i=6;
+    UPDATE t1 SET b=randomblob(2048) WHERE i=7;
+    ROLLBACK TO one;
+    INSERT INTO t1 VALUES(8, NULL, 'eight');
+  COMMIT;
+} {}
+
+do_execsql_test 3.2 {
+  SELECT i, t FROM t1
+} {1 one   2 two   8 eight}
+
+forcecopy test.db test2.db
+forcecopy test.db-wal test2.db-wal
+
+sqlite3 db2 test2.db
+do_test 1.3 {
+  execsql {
+    SELECT i, t FROM t1
+  } db2
+} {1 one   2 two   8 eight}
+
+catch { db2 close }
+
+#-------------------------------------------------------------------------
+reset_db
+
+do_execsql_test 4.0 {
+  PRAGMA synchronous = NORMAL;
+  PRAGMA journal_mode = WAL;
+  PRAGMA cache_size = 1;
+
+  CREATE TABLE t1 (i INTEGER PRIMARY KEY, b BLOB, t TEXT);
+  PRAGMA wal_checkpoint;
+  INSERT INTO t1 VALUES(1, randomblob(2048), 'one');
+} {wal 0 2 2}
+
+do_execsql_test 4.1.1 {
+  SAVEPOINT one;
+    INSERT INTO t1 VALUES(2, randomblob(2048), 'two');
+    INSERT INTO t1 VALUES(3, randomblob(2048), 'three');
+    INSERT INTO t1 VALUES(4, randomblob(2048), 'four');
+    INSERT INTO t1 VALUES(5, randomblob(2048), 'five');
+    INSERT INTO t1 VALUES(6, randomblob(2048), 'six');
+    INSERT INTO t1 VALUES(7, randomblob(2048), 'seven');
+
+    UPDATE t1 SET b=randomblob(2048) WHERE i=5;
+    UPDATE t1 SET b=randomblob(2048) WHERE i=6;
+    UPDATE t1 SET b=randomblob(2048) WHERE i=7;
+}
+
+do_execsql_test 4.1.2 {
+    ROLLBACK TO one;
+    INSERT INTO t1 VALUES(8, NULL, 'eight');
+  RELEASE one;
+} {}
+
+do_execsql_test 4.2 {
+  SELECT i, t FROM t1
+} {1 one   8 eight}
+
+forcecopy test.db test2.db
+forcecopy test.db-wal test2.db-wal
+
+sqlite3 db2 test2.db
+do_test 4.3 {
+  execsql {
+    SELECT i, t FROM t1
+  } db2
+} {1 one   8 eight}
+
+catch { db2 close }
+
+#-------------------------------------------------------------------------
+reset_db
+
+do_execsql_test 5.0 {
+  PRAGMA synchronous = NORMAL;
+  PRAGMA journal_mode = WAL;
+  PRAGMA cache_size = 1;
+
+  CREATE TABLE t1 (i INTEGER PRIMARY KEY, b BLOB, t TEXT);
+  INSERT INTO t1 VALUES(1, randomblob(2048), 'one');
+  INSERT INTO t1 VALUES(2, randomblob(2048), 'two');
+  INSERT INTO t1 VALUES(3, randomblob(2048), 'three');
+  PRAGMA wal_checkpoint;
+} {wal 0 14 14}
+
+do_execsql_test 5.1 {
+  BEGIN;
+    SELECT count(*) FROM t1;
+    SAVEPOINT one;
+    INSERT INTO t1 VALUES(4, randomblob(2048), 'four');
+    INSERT INTO t1 VALUES(5, randomblob(2048), 'five');
+    INSERT INTO t1 VALUES(6, randomblob(2048), 'six');
+    INSERT INTO t1 VALUES(7, randomblob(2048), 'seven');
+    ROLLBACK TO one;
+    INSERT INTO t1 VALUES(8, randomblob(2048), 'eight');
+    INSERT INTO t1 VALUES(9, randomblob(2048), 'nine');
+  COMMIT;
+} {3}
+
+forcecopy test.db test2.db
+forcecopy test.db-wal test2.db-wal
+
+sqlite3 db2 test2.db
+do_test 5.2 {
+  execsql {
+    SELECT i, t FROM t1
+  } db2
+} {1 one  2 two   3 three  8 eight 9 nine}
+db2 close
+
+do_execsql_test 5.3 {
+  SELECT i, t FROM t1
+} {1 one  2 two   3 three  8 eight 9 nine}
+
   
 finish_test