Merge trunk changes into this branch.

FossilOrigin-Name: 3e2893097c59820def88bb4739189c9c9a4f70a98a0a72b81959658f069715f6

16 files changed, 181 insertions, 168 deletions

diff --git a/src/dbpage.c b/src/dbpage.c
index 124952456..74f345570 100644
--- a/src/dbpage.c
+++ b/src/dbpage.c
@@ -428,7 +428,11 @@ static int dbpageSync(sqlite3_vtab *pVtab){
   if( pTab->pgnoTrunc>0 ){
     Btree *pBt = pTab->db->aDb[pTab->iDbTrunc].pBt;
     Pager *pPager = sqlite3BtreePager(pBt);
-    sqlite3PagerTruncateImage(pPager, pTab->pgnoTrunc);
+    sqlite3BtreeEnter(pBt);
+    if( pTab->pgnoTrunc<sqlite3BtreeLastPage(pBt) ){
+      sqlite3PagerTruncateImage(pPager, pTab->pgnoTrunc);
+    }
+    sqlite3BtreeLeave(pBt);
   }
   pTab->pgnoTrunc = 0;
   return SQLITE_OK;
diff --git a/src/expr.c b/src/expr.c
index 37923bc84..86c966683 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -479,7 +479,7 @@ static int codeCompare(
   p5 = binaryCompareP5(pLeft, pRight, jumpIfNull);
   addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
                            (void*)p4, P4_COLLSEQ);
-  sqlite3VdbeChangeP5(pParse->pVdbe, (u8)p5);
+  sqlite3VdbeChangeP5(pParse->pVdbe, (u16)p5);
   return addr;
 }
 
diff --git a/src/func.c b/src/func.c
index 2d25803e0..a4b72ecc4 100644
--- a/src/func.c
+++ b/src/func.c
@@ -363,7 +363,7 @@ static void substrFunc(
     return;
   }
   p0type = sqlite3_value_type(argv[0]);
-  p1 = sqlite3_value_int(argv[1]);
+  p1 = sqlite3_value_int64(argv[1]);
   if( p0type==SQLITE_BLOB ){
     len = sqlite3_value_bytes(argv[0]);
     z = sqlite3_value_blob(argv[0]);
@@ -388,7 +388,7 @@ static void substrFunc(
   if( p1==0 ) p1 = 1; /* <rdar://problem/6778339> */
 #endif
   if( argc==3 ){
-    p2 = sqlite3_value_int(argv[2]);
+    p2 = sqlite3_value_int64(argv[2]);
     if( p2<0 ){
       p2 = -p2;
       negP2 = 1;
@@ -427,9 +427,11 @@ static void substrFunc(
     sqlite3_result_text64(context, (char*)z, z2-z, SQLITE_TRANSIENT,
                           SQLITE_UTF8);
   }else{
-    if( p1+p2>len ){
+    if( p1>=len ){
+      p1 = p2 = 0;
+    }else if( p2>len-p1 ){
       p2 = len-p1;
-      if( p2<0 ) p2 = 0;
+      assert( p2>0 );
     }
     sqlite3_result_blob64(context, (char*)&z[p1], (u64)p2, SQLITE_TRANSIENT);
   }
@@ -440,13 +442,13 @@ static void substrFunc(
 */
 #ifndef SQLITE_OMIT_FLOATING_POINT
 static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
-  int n = 0;
+  i64 n = 0;
   double r;
   char *zBuf;
   assert( argc==1 || argc==2 );
   if( argc==2 ){
     if( SQLITE_NULL==sqlite3_value_type(argv[1]) ) return;
-    n = sqlite3_value_int(argv[1]);
+    n = sqlite3_value_int64(argv[1]);
     if( n>30 ) n = 30;
     if( n<0 ) n = 0;
   }
@@ -461,7 +463,7 @@ static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   }else if( n==0 ){ 
     r = (double)((sqlite_int64)(r+(r<0?-0.5:+0.5)));
   }else{
-    zBuf = sqlite3_mprintf("%!.*f",n,r);
+    zBuf = sqlite3_mprintf("%!.*f",(int)n,r);
     if( zBuf==0 ){
       sqlite3_result_error_nomem(context);
       return;
diff --git a/src/main.c b/src/main.c
index 3a535e3cd..1163deb6e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -2857,8 +2857,8 @@ static const int aHardLimit[] = {
 #if SQLITE_MAX_VDBE_OP<40
 # error SQLITE_MAX_VDBE_OP must be at least 40
 #endif
-#if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
-# error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
+#if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>32767
+# error SQLITE_MAX_FUNCTION_ARG must be between 0 and 32767
 #endif
 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
 # error SQLITE_MAX_ATTACHED must be between 0 and 125
@@ -4271,7 +4271,6 @@ int sqlite3_test_control(int op, ...){
       ** issue "defined but not used" warnings. */
       if( x==9999 ){
         sqlite3ShowExpr(0);
-        sqlite3ShowExpr(0);
         sqlite3ShowExprList(0);
         sqlite3ShowIdList(0);
         sqlite3ShowSrcList(0);
@@ -4288,7 +4287,6 @@ int sqlite3_test_control(int op, ...){
         sqlite3ShowWinFunc(0);
 #endif
         sqlite3ShowSelect(0);
-        sqlite3ShowWhereTerm(0);
       }
 #endif
       break;
diff --git a/src/pager.c b/src/pager.c
index 4f616f0c7..e2dbbeae3 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -789,20 +789,6 @@ static const unsigned char aJournalMagic[] = {
 # define USEFETCH(x) 0
 #endif
 
-/*
-** The argument to this macro is a file descriptor (type sqlite3_file*).
-** Return 0 if it is not open, or non-zero (but not 1) if it is.
-**
-** This is so that expressions can be written as:
-**
-**   if( isOpen(pPager->jfd) ){ ...
-**
-** instead of
-**
-**   if( pPager->jfd->pMethods ){ ...
-*/
-#define isOpen(pFd) ((pFd)->pMethods!=0)
-
 #ifdef SQLITE_DIRECT_OVERFLOW_READ
 /*
 ** Return true if page pgno can be read directly from the database file
@@ -2088,7 +2074,7 @@ static int pager_end_transaction(Pager *pPager, int hasSuper, int bCommit){
       }
       pPager->journalOff = 0;
     }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
-      || (pPager->exclusiveMode && pPager->journalMode!=PAGER_JOURNALMODE_WAL)
+      || (pPager->exclusiveMode && pPager->journalMode<PAGER_JOURNALMODE_WAL)
     ){
       rc = zeroJournalHdr(pPager, hasSuper||pPager->tempFile);
       pPager->journalOff = 0;
diff --git a/src/pager.h b/src/pager.h
index 7ef9a237a..9b2cfc0bc 100644
--- a/src/pager.h
+++ b/src/pager.h
@@ -83,6 +83,22 @@ typedef struct PgHdr DbPage;
 #define PAGER_JOURNALMODE_MEMORY      4   /* In-memory journal file */
 #define PAGER_JOURNALMODE_WAL         5   /* Use write-ahead logging */
 
+#define isWalMode(x) ((x)==PAGER_JOURNALMODE_WAL)
+
+/*
+** The argument to this macro is a file descriptor (type sqlite3_file*).
+** Return 0 if it is not open, or non-zero (but not 1) if it is.
+**
+** This is so that expressions can be written as:
+**
+**   if( isOpen(pPager->jfd) ){ ...
+**
+** instead of
+**
+**   if( pPager->jfd->pMethods ){ ...
+*/
+#define isOpen(pFd) ((pFd)->pMethods!=0)
+
 /*
 ** Flags that make up the mask passed to sqlite3PagerGet().
 */
diff --git a/src/pragma.c b/src/pragma.c
index ae0c86f03..291ccf7af 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -1761,7 +1761,7 @@ void sqlite3Pragma(
 
       /* Do the b-tree integrity checks */
       sqlite3VdbeAddOp4(v, OP_IntegrityCk, 1, cnt, 8, (char*)aRoot,P4_INTARRAY);
-      sqlite3VdbeChangeP5(v, (u8)i);
+      sqlite3VdbeChangeP5(v, (u16)i);
       addr = sqlite3VdbeAddOp1(v, OP_IsNull, 2); VdbeCoverage(v);
       sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
          sqlite3MPrintf(db, "*** in database %s ***\n", db->aDb[i].zDbSName),
diff --git a/src/select.c b/src/select.c
index 9d35e1832..cf25c8e67 100644
--- a/src/select.c
+++ b/src/select.c
@@ -6826,7 +6826,7 @@ static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
       }
       sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, AggInfoFuncReg(pAggInfo,i));
       sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
-      sqlite3VdbeChangeP5(v, (u8)nArg);
+      sqlite3VdbeChangeP5(v, (u16)nArg);
       sqlite3VdbeAddOp2(v, OP_Next, pF->iOBTab, iTop+1); VdbeCoverage(v);
       sqlite3VdbeJumpHere(v, iTop);
       sqlite3ReleaseTempRange(pParse, regAgg, nArg);
@@ -6989,7 +6989,7 @@ static void updateAccumulator(
       }
       sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, AggInfoFuncReg(pAggInfo,i));
       sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
-      sqlite3VdbeChangeP5(v, (u8)nArg);
+      sqlite3VdbeChangeP5(v, (u16)nArg);
       sqlite3ReleaseTempRange(pParse, regAgg, nArg);
     }
     if( addrNext ){
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index dbdf36200..b8c9136a5 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1925,7 +1925,7 @@ struct sqlite3 {
 ** field is used by per-connection app-def functions.
 */
 struct FuncDef {
-  i8 nArg;             /* Number of arguments.  -1 means unlimited */
+  i16 nArg;            /* Number of arguments.  -1 means unlimited */
   u32 funcFlags;       /* Some combination of SQLITE_FUNC_* */
   void *pUserData;     /* User data parameter */
   FuncDef *pNext;      /* Next function with same name */
diff --git a/src/sqliteLimit.h b/src/sqliteLimit.h
index c7185b1c5..620b0f8e5 100644
--- a/src/sqliteLimit.h
+++ b/src/sqliteLimit.h
@@ -89,9 +89,13 @@
 
 /*
 ** The maximum number of arguments to an SQL function.
+**
+** This value has a hard upper limit of 32767 due to storage
+** constraints (it needs to fit inside a i16).  We keep it
+** lower than that to prevent abuse.
 */
 #ifndef SQLITE_MAX_FUNCTION_ARG
-# define SQLITE_MAX_FUNCTION_ARG 127
+# define SQLITE_MAX_FUNCTION_ARG 1000
 #endif
 
 /*
diff --git a/src/test_func.c b/src/test_func.c
index 8c06705ae..82f7b3d9c 100644
--- a/src/test_func.c
+++ b/src/test_func.c
@@ -773,7 +773,7 @@ static int SQLITE_TCLAPI abuse_create_function(
   rc = sqlite3_create_function(db, "tx", -2, SQLITE_UTF8, 0, tStep, 0, 0);
   if( rc!=SQLITE_MISUSE ) goto abuse_err;
 
-  rc = sqlite3_create_function(db, "tx", 128, SQLITE_UTF8, 0, tStep, 0, 0);
+  rc = sqlite3_create_function(db, "tx", 32768, SQLITE_UTF8, 0, tStep, 0, 0);
   if( rc!=SQLITE_MISUSE ) goto abuse_err;
 
   rc = sqlite3_create_function(db, "funcxx"
@@ -789,7 +789,7 @@ static int SQLITE_TCLAPI abuse_create_function(
   ** a no-op function (that always returns NULL) and which has the
   ** maximum-length function name and the maximum number of parameters.
   */
-  sqlite3_limit(db, SQLITE_LIMIT_FUNCTION_ARG, 10000);
+  sqlite3_limit(db, SQLITE_LIMIT_FUNCTION_ARG, 1000000);
   mxArg = sqlite3_limit(db, SQLITE_LIMIT_FUNCTION_ARG, -1);
   rc = sqlite3_create_function(db, "nullx"
        "_123456789_123456789_123456789_123456789_123456789"
diff --git a/src/trigger.c b/src/trigger.c
index ff2df82cb..e306a2e66 100644
--- a/src/trigger.c
+++ b/src/trigger.c
@@ -1409,7 +1409,7 @@ void sqlite3CodeRowTriggerDirect(
     ** invocation is disallowed if (a) the sub-program is really a trigger,
     ** not a foreign key action, and (b) the flag to enable recursive triggers
     ** is clear.  */
-    sqlite3VdbeChangeP5(v, (u8)bRecursive);
+    sqlite3VdbeChangeP5(v, (u16)bRecursive);
   }
 }
 
diff --git a/src/vdbeInt.h b/src/vdbeInt.h
index 467f48890..2cb4f8c2a 100644
--- a/src/vdbeInt.h
+++ b/src/vdbeInt.h
@@ -393,7 +393,7 @@ struct sqlite3_context {
   int isError;            /* Error code returned by the function. */
   u8 enc;                 /* Encoding to use for results */
   u8 skipFlag;            /* Skip accumulator loading if true */
-  u8 argc;                /* Number of arguments */
+  u16 argc;               /* Number of arguments */
   sqlite3_value *argv[1]; /* Argument set */
 };
 
diff --git a/src/wal.c b/src/wal.c
index ea9bc4df8..42ce3cb97 100644
--- a/src/wal.c
+++ b/src/wal.c
@@ -2986,11 +2986,7 @@ static int walBeginShmUnreliable(Wal *pWal, int *pChanged){
 */
 static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
   volatile WalCkptInfo *pInfo;    /* Checkpoint information in wal-index */
-  u32 mxReadMark;                 /* Largest aReadMark[] value */
-  int mxI;                        /* Index of largest aReadMark[] value */
-  int i;                          /* Loop counter */
   int rc = SQLITE_OK;             /* Return code  */
-  u32 mxFrame;                    /* Wal frame to lock to */
 #ifdef SQLITE_ENABLE_SETLK_TIMEOUT
   int nBlockTmout = 0;
 #endif
@@ -3096,141 +3092,147 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
   assert( pWal->apWiData[0]!=0 );
   pInfo = walCkptInfo(pWal);
   SEH_INJECT_FAULT;
-  if( !useWal && AtomicLoad(&pInfo->nBackfill)==pWal->hdr.mxFrame
+  {
+    u32 mxReadMark;               /* Largest aReadMark[] value */
+    int mxI;                      /* Index of largest aReadMark[] value */
+    int i;                        /* Loop counter */
+    u32 mxFrame;                  /* Wal frame to lock to */
+    if( !useWal && AtomicLoad(&pInfo->nBackfill)==pWal->hdr.mxFrame
 #ifdef SQLITE_ENABLE_SNAPSHOT
-   && ((pWal->bGetSnapshot==0 && pWal->pSnapshot==0) || pWal->hdr.mxFrame==0)
+     && ((pWal->bGetSnapshot==0 && pWal->pSnapshot==0) || pWal->hdr.mxFrame==0)
 #endif
-  ){
-    /* The WAL has been completely backfilled (or it is empty).
-    ** and can be safely ignored.
-    */
-    rc = walLockShared(pWal, WAL_READ_LOCK(0));
-    walShmBarrier(pWal);
-    if( rc==SQLITE_OK ){
-      if( memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr)) ){
-        /* It is not safe to allow the reader to continue here if frames
-        ** may have been appended to the log before READ_LOCK(0) was obtained.
-        ** When holding READ_LOCK(0), the reader ignores the entire log file,
-        ** which implies that the database file contains a trustworthy
-        ** snapshot. Since holding READ_LOCK(0) prevents a checkpoint from
-        ** happening, this is usually correct.
-        **
-        ** However, if frames have been appended to the log (or if the log
-        ** is wrapped and written for that matter) before the READ_LOCK(0)
-        ** is obtained, that is not necessarily true. A checkpointer may
-        ** have started to backfill the appended frames but crashed before
-        ** it finished. Leaving a corrupt image in the database file.
-        */
-        walUnlockShared(pWal, WAL_READ_LOCK(0));
-        return WAL_RETRY;
+    ){
+      /* The WAL has been completely backfilled (or it is empty).
+      ** and can be safely ignored.
+      */
+      rc = walLockShared(pWal, WAL_READ_LOCK(0));
+      walShmBarrier(pWal);
+      if( rc==SQLITE_OK ){
+        if( memcmp((void *)walIndexHdr(pWal), &pWal->hdr,sizeof(WalIndexHdr)) ){
+          /* It is not safe to allow the reader to continue here if frames
+          ** may have been appended to the log before READ_LOCK(0) was obtained.
+          ** When holding READ_LOCK(0), the reader ignores the entire log file,
+          ** which implies that the database file contains a trustworthy
+          ** snapshot. Since holding READ_LOCK(0) prevents a checkpoint from
+          ** happening, this is usually correct.
+          **
+          ** However, if frames have been appended to the log (or if the log
+          ** is wrapped and written for that matter) before the READ_LOCK(0)
+          ** is obtained, that is not necessarily true. A checkpointer may
+          ** have started to backfill the appended frames but crashed before
+          ** it finished. Leaving a corrupt image in the database file.
+          */
+          walUnlockShared(pWal, WAL_READ_LOCK(0));
+          return WAL_RETRY;
+        }
+        pWal->readLock = 0;
+        return SQLITE_OK;
+      }else if( rc!=SQLITE_BUSY ){
+        return rc;
       }
-      pWal->readLock = 0;
-      return SQLITE_OK;
-    }else if( rc!=SQLITE_BUSY ){
-      return rc;
     }
-  }
-
-  /* If we get this far, it means that the reader will want to use
-  ** the WAL to get at content from recent commits.  The job now is
-  ** to select one of the aReadMark[] entries that is closest to
-  ** but not exceeding pWal->hdr.mxFrame and lock that entry.
-  */
-  mxReadMark = 0;
-  mxI = 0;
-  mxFrame = pWal->hdr.mxFrame;
+  
+    /* If we get this far, it means that the reader will want to use
+    ** the WAL to get at content from recent commits.  The job now is
+    ** to select one of the aReadMark[] entries that is closest to
+    ** but not exceeding pWal->hdr.mxFrame and lock that entry.
+    */
+    mxReadMark = 0;
+    mxI = 0;
+    mxFrame = pWal->hdr.mxFrame;
 #ifdef SQLITE_ENABLE_SNAPSHOT
-  if( pWal->pSnapshot && pWal->pSnapshot->mxFrame<mxFrame ){
-    mxFrame = pWal->pSnapshot->mxFrame;
-  }
-#endif
-  for(i=1; i<WAL_NREADER; i++){
-    u32 thisMark = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
-    if( mxReadMark<=thisMark && thisMark<=mxFrame ){
-      assert( thisMark!=READMARK_NOT_USED );
-      mxReadMark = thisMark;
-      mxI = i;
+    if( pWal->pSnapshot && pWal->pSnapshot->mxFrame<mxFrame ){
+      mxFrame = pWal->pSnapshot->mxFrame;
     }
-  }
-  if( (pWal->readOnly & WAL_SHM_RDONLY)==0
-   && (mxReadMark<mxFrame || mxI==0)
-  ){
+#endif
     for(i=1; i<WAL_NREADER; i++){
-      rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
-      if( rc==SQLITE_OK ){
-        AtomicStore(pInfo->aReadMark+i,mxFrame);
-        mxReadMark = mxFrame;
+      u32 thisMark = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
+      if( mxReadMark<=thisMark && thisMark<=mxFrame ){
+        assert( thisMark!=READMARK_NOT_USED );
+        mxReadMark = thisMark;
         mxI = i;
-        walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
-        break;
-      }else if( rc!=SQLITE_BUSY ){
-        return rc;
       }
     }
-  }
-  if( mxI==0 ){
-    assert( rc==SQLITE_BUSY || (pWal->readOnly & WAL_SHM_RDONLY)!=0 );
-    return rc==SQLITE_BUSY ? WAL_RETRY : SQLITE_READONLY_CANTINIT;
-  }
-
-  (void)walEnableBlockingMs(pWal, nBlockTmout);
-  rc = walLockShared(pWal, WAL_READ_LOCK(mxI));
-  walDisableBlocking(pWal);
-  if( rc ){
-#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
-    if( rc==SQLITE_BUSY_TIMEOUT ){
-      *pCnt |= WAL_RETRY_BLOCKED_MASK;
+    if( (pWal->readOnly & WAL_SHM_RDONLY)==0
+     && (mxReadMark<mxFrame || mxI==0)
+    ){
+      for(i=1; i<WAL_NREADER; i++){
+        rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
+        if( rc==SQLITE_OK ){
+          AtomicStore(pInfo->aReadMark+i,mxFrame);
+          mxReadMark = mxFrame;
+          mxI = i;
+          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
+          break;
+        }else if( rc!=SQLITE_BUSY ){
+          return rc;
+        }
+      }
+    }
+    if( mxI==0 ){
+      assert( rc==SQLITE_BUSY || (pWal->readOnly & WAL_SHM_RDONLY)!=0 );
+      return rc==SQLITE_BUSY ? WAL_RETRY : SQLITE_READONLY_CANTINIT;
     }
+  
+    (void)walEnableBlockingMs(pWal, nBlockTmout);
+    rc = walLockShared(pWal, WAL_READ_LOCK(mxI));
+    walDisableBlocking(pWal);
+    if( rc ){
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+      if( rc==SQLITE_BUSY_TIMEOUT ){
+        *pCnt |= WAL_RETRY_BLOCKED_MASK;
+      }
 #else
-    assert( rc!=SQLITE_BUSY_TIMEOUT );
+      assert( rc!=SQLITE_BUSY_TIMEOUT );
 #endif
-    assert( (rc&0xFF)!=SQLITE_BUSY||rc==SQLITE_BUSY||rc==SQLITE_BUSY_TIMEOUT );
-    return (rc&0xFF)==SQLITE_BUSY ? WAL_RETRY : rc;
-  }
-  /* Now that the read-lock has been obtained, check that neither the
-  ** value in the aReadMark[] array or the contents of the wal-index
-  ** header have changed.
-  **
-  ** It is necessary to check that the wal-index header did not change
-  ** between the time it was read and when the shared-lock was obtained
-  ** on WAL_READ_LOCK(mxI) was obtained to account for the possibility
-  ** that the log file may have been wrapped by a writer, or that frames
-  ** that occur later in the log than pWal->hdr.mxFrame may have been
-  ** copied into the database by a checkpointer. If either of these things
-  ** happened, then reading the database with the current value of
-  ** pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry
-  ** instead.
-  **
-  ** Before checking that the live wal-index header has not changed
-  ** since it was read, set Wal.minFrame to the first frame in the wal
-  ** file that has not yet been checkpointed. This client will not need
-  ** to read any frames earlier than minFrame from the wal file - they
-  ** can be safely read directly from the database file.
-  **
-  ** Because a ShmBarrier() call is made between taking the copy of
-  ** nBackfill and checking that the wal-header in shared-memory still
-  ** matches the one cached in pWal->hdr, it is guaranteed that the
-  ** checkpointer that set nBackfill was not working with a wal-index
-  ** header newer than that cached in pWal->hdr. If it were, that could
-  ** cause a problem. The checkpointer could omit to checkpoint
-  ** a version of page X that lies before pWal->minFrame (call that version
-  ** A) on the basis that there is a newer version (version B) of the same
-  ** page later in the wal file. But if version B happens to like past
-  ** frame pWal->hdr.mxFrame - then the client would incorrectly assume
-  ** that it can read version A from the database file. However, since
-  ** we can guarantee that the checkpointer that set nBackfill could not
-  ** see any pages past pWal->hdr.mxFrame, this problem does not come up.
-  */
-  pWal->minFrame = AtomicLoad(&pInfo->nBackfill)+1; SEH_INJECT_FAULT;
-  walShmBarrier(pWal);
-  if( AtomicLoad(pInfo->aReadMark+mxI)!=mxReadMark
-   || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
-  ){
-    walUnlockShared(pWal, WAL_READ_LOCK(mxI));
-    return WAL_RETRY;
-  }else{
-    assert( mxReadMark<=pWal->hdr.mxFrame );
-    pWal->readLock = (i16)mxI;
+      assert((rc&0xFF)!=SQLITE_BUSY||rc==SQLITE_BUSY||rc==SQLITE_BUSY_TIMEOUT);
+      return (rc&0xFF)==SQLITE_BUSY ? WAL_RETRY : rc;
+    }
+    /* Now that the read-lock has been obtained, check that neither the
+    ** value in the aReadMark[] array or the contents of the wal-index
+    ** header have changed.
+    **
+    ** It is necessary to check that the wal-index header did not change
+    ** between the time it was read and when the shared-lock was obtained
+    ** on WAL_READ_LOCK(mxI) was obtained to account for the possibility
+    ** that the log file may have been wrapped by a writer, or that frames
+    ** that occur later in the log than pWal->hdr.mxFrame may have been
+    ** copied into the database by a checkpointer. If either of these things
+    ** happened, then reading the database with the current value of
+    ** pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry
+    ** instead.
+    **
+    ** Before checking that the live wal-index header has not changed
+    ** since it was read, set Wal.minFrame to the first frame in the wal
+    ** file that has not yet been checkpointed. This client will not need
+    ** to read any frames earlier than minFrame from the wal file - they
+    ** can be safely read directly from the database file.
+    **
+    ** Because a ShmBarrier() call is made between taking the copy of
+    ** nBackfill and checking that the wal-header in shared-memory still
+    ** matches the one cached in pWal->hdr, it is guaranteed that the
+    ** checkpointer that set nBackfill was not working with a wal-index
+    ** header newer than that cached in pWal->hdr. If it were, that could
+    ** cause a problem. The checkpointer could omit to checkpoint
+    ** a version of page X that lies before pWal->minFrame (call that version
+    ** A) on the basis that there is a newer version (version B) of the same
+    ** page later in the wal file. But if version B happens to like past
+    ** frame pWal->hdr.mxFrame - then the client would incorrectly assume
+    ** that it can read version A from the database file. However, since
+    ** we can guarantee that the checkpointer that set nBackfill could not
+    ** see any pages past pWal->hdr.mxFrame, this problem does not come up.
+    */
+    pWal->minFrame = AtomicLoad(&pInfo->nBackfill)+1; SEH_INJECT_FAULT;
+    walShmBarrier(pWal);
+    if( AtomicLoad(pInfo->aReadMark+mxI)!=mxReadMark
+     || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
+    ){
+      walUnlockShared(pWal, WAL_READ_LOCK(mxI));
+      return WAL_RETRY;
+    }else{
+      assert( mxReadMark<=pWal->hdr.mxFrame );
+      pWal->readLock = (i16)mxI;
+    }
   }
   return rc;
 }
@@ -3737,12 +3739,12 @@ int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
 
     SEH_TRY {
       /* Restore the clients cache of the wal-index header to the state it
-      ** was in before the client began writing to the database. 
+      ** was in before the client began writing to the database.
       */
       memcpy(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr));
-  
-      for(iFrame=pWal->hdr.mxFrame+1; 
-          ALWAYS(rc==SQLITE_OK) && iFrame<=iMax; 
+
+      for(iFrame=pWal->hdr.mxFrame+1;
+          ALWAYS(rc==SQLITE_OK) && iFrame<=iMax;
           iFrame++
       ){
         /* This call cannot fail. Unless the page for which the page number
diff --git a/src/where.c b/src/where.c
index 20ebaa8cd..c9698699b 100644
--- a/src/where.c
+++ b/src/where.c
@@ -7144,6 +7144,7 @@ whereBeginError:
   ){
     if( (db->flags & SQLITE_VdbeAddopTrace)==0 ) return;
     sqlite3VdbePrintOp(0, pc, pOp);
+    sqlite3ShowWhereTerm(0); /* So compiler won't complain about unused func */
   }
 #endif
 
diff --git a/src/window.c b/src/window.c
index acc6ea854..8373e3641 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1751,7 +1751,7 @@ static void windowAggStep(
       sqlite3VdbeAddOp3(v, bInverse? OP_AggInverse : OP_AggStep,
                         bInverse, regArg, pWin->regAccum);
       sqlite3VdbeAppendP4(v, pFunc, P4_FUNCDEF);
-      sqlite3VdbeChangeP5(v, (u8)nArg);
+      sqlite3VdbeChangeP5(v, (u16)nArg);
       if( pWin->bExprArgs ){
         sqlite3ReleaseTempRange(pParse, regArg, nArg);
       }