Use NEVER and ALWAYS macros to confirm that the return value from

sqlite3ExprSkipCollateAndLikely() is never NULL in some of its use cases.

FossilOrigin-Name: 76d2eb86e109fc3cbdba2e8175c22ed7660b59bb9315f6c55c565587f33ad43b

manifest

@@ -1,5 +1,5 @@
-C Add\sALWAYS()\sto\sconditionals\sassociated\swith\sSHM\slocking\sthat\sare\salways\strue.
+C Use\sNEVER\sand\sALWAYS\smacros\sto\sconfirm\sthat\sthe\sreturn\svalue\sfrom\nsqlite3ExprSkipCollateAndLikely()\sis\snever\sNULL\sin\ssome\sof\sits\suse\scases.
-D 2020-11-06T16:48:55.396
+D 2020-11-08T20:44:30.361
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -489,7 +489,7 @@ F src/date.c dace306a10d9b02ee553d454c8e1cf8d3c9b932e137738a6b15b90253a9bfc10
 F src/dbpage.c 8a01e865bf8bc6d7b1844b4314443a6436c07c3efe1d488ed89e81719047833a
 F src/dbstat.c 3aa79fc3aed7ce906e4ea6c10e85d657299e304f6049861fe300053ac57de36c
 F src/delete.c 927cf8f900583e79aca8f1a321979e0a8f053babd9a690b44b38f79de2cc09fe
-F src/expr.c 2cfe739c81e9751123b900dee54f6d34f8ec4b747515a51f1771de8e2840650d
+F src/expr.c 0d196ed5a2ebf96be7e8df88add4fabfad0dce16c0fed81a4b8f6a26e259797f
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 83372403298e6a7dd989a47aaacdbaa5b4307b5199dbd56e07d4896066b3de72
 F src/func.c 2333eb4277f55a5efdc12ef754e7d7ec9105d257b2fd00301d23ce1e8fa67dc0
@@ -535,9 +535,9 @@ F src/pragma.h 8dc78ab7e9ec6ce3ded8332810a2066f1ef6267e2e03cd7356ee00276125c6cf
 F src/prepare.c 270170a239c0f66bd3c228f373afe24447c2614a6829ae22080babc64f241931
 F src/printf.c 30e92b638fac71dcd85cdea1d12ecfae354c9adee2c71e8e1ae4727cde7c91ed
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
-F src/resolve.c 97b91fb25d86881ff20c9ad2ad98412c6c1bb5f7d6c9bb044db250cbc9cfcd4b
+F src/resolve.c 1948a92ca9eab776632816b97e57c61d933474a78aad4f4ef835c916a83dbb1c
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c 507c541942d78a9af1d4680e6addf60b677d8fc6d55f0b0a047a01759f0c0386
+F src/select.c 31387e56f5e6d1adc798dfa04b946001289a61e65acf4615f7b7130f121f3b9c
 F src/shell.c.in c0b4aea11596235e4206d671568590f9516f6db63755e82661cb75b662e3cbf2
 F src/sqlite.h.in ff32663b457306eb88c3039868280aa39da31162ed69c4e71fa8e028684e7277
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -624,10 +624,10 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 69e770e96fd56cc21608992bf2c6f1f3dc5cf2572d0495c6a643b06c3a679f14
 F src/wal.h c3aa7825bfa2fe0d85bef2db94655f99870a285778baa36307c0a16da32b226a
 F src/walker.c 3df26a33dc4f54e8771600fb7fdebe1ece0896c2ad68c30ab40b017aa4395049
-F src/where.c 03d35ea488e694849923e28ccdce1ef377a5c3738405b5323ff97eb9aa7569c1
+F src/where.c 21f472adb5217f907d7e6d3aa8194f181ded3c04696933992a8632cf51a5ec5e
 F src/whereInt.h 59077fbd0b3d01bc8715e746c86a99ebf4c85bde8a57077ec04d2a23e59666ec
 F src/wherecode.c a3a1aff30fe99a818d8e7c607980f033f40c68d890e03ed25838b9dbb7908bee
-F src/whereexpr.c 2a05552e808047a93845278c98c6ca64a265fa8e9ffd087c161bb11bfe339866
+F src/whereexpr.c 3a463e156ea388083c501502229c2c7f4f5c6b5330ea59bdf40d6eb6e155a25f
 F src/window.c edd6f5e25a1e8f2b6f5305b7f5f7da7bb35f07f0d432b255b1d4c2fcab4205aa
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test ce1aafc86e110685b324e9a763eab4f2a73f737842ec3b687bd965867de90627
@@ -1883,7 +1883,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 991ca9b26bacd8f6b64498057fe28f2068466a220f372fd365b6685f583f0e92
+P b599e89076d60afede7d2b3503b9338ca863d0c2d25799afe4080a6186386ea9
-R f26b9e90b790a8d006742a6dcee07267
+R 7beca53d7c8d22c465c9d56afbdf86de
 U drh
-Z 453afee97587daa6fc13b031ff46a5e1
+Z c36c228a67de698bd35d3d99e8941c75

manifest.uuid

@@ -1 +1 @@
-b599e89076d60afede7d2b3503b9338ca863d0c2d25799afe4080a6186386ea9
+76d2eb86e109fc3cbdba2e8175c22ed7660b59bb9315f6c55c565587f33ad43b

src/expr.c

@@ -3623,6 +3623,7 @@ void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
 */
 static void exprToRegister(Expr *pExpr, int iReg){
   Expr *p = sqlite3ExprSkipCollateAndLikely(pExpr);
+  if( NEVER(p==0) ) return;
   p->op2 = p->op;
   p->op = TK_REGISTER;
   p->iTable = iReg;
@@ -4610,6 +4611,7 @@ int sqlite3ExprCodeTemp(Parse *pParse, Expr *pExpr, int *pReg){
   int r2;
   pExpr = sqlite3ExprSkipCollateAndLikely(pExpr);
   if( ConstFactorOk(pParse)
+   && ALWAYS(pExpr!=0)
    && pExpr->op!=TK_REGISTER
    && sqlite3ExprIsConstantNotJoin(pExpr)
   ){

src/resolve.c

@@ -1284,6 +1284,7 @@ static int resolveCompoundOrderBy(
       Expr *pE, *pDup;
       if( pItem->done ) continue;
       pE = sqlite3ExprSkipCollateAndLikely(pItem->pExpr);
+      if( NEVER(pE==0) ) continue;
       if( sqlite3ExprIsInteger(pE, &iCol) ){
         if( iCol<=0 || iCol>pEList->nExpr ){
           resolveOutOfRangeError(pParse, "ORDER", i+1, pEList->nExpr);
@@ -1463,6 +1464,7 @@ static int resolveOrderGroupBy(
   for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
     Expr *pE = pItem->pExpr;
     Expr *pE2 = sqlite3ExprSkipCollateAndLikely(pE);
+    if( NEVER(pE2==0) ) continue;
     if( zType[0]!='G' ){
       iCol = resolveAsName(pParse, pSelect->pEList, pE2);
       if( iCol>0 ){

src/select.c

@@ -1995,7 +1995,7 @@ int sqlite3ColumnsFromExprList(
       /* If the column contains an "AS <name>" phrase, use <name> as the name */
     }else{
       Expr *pColExpr = sqlite3ExprSkipCollateAndLikely(pEList->a[i].pExpr);
-      while( pColExpr->op==TK_DOT ){
+      while( ALWAYS(pColExpr!=0) && pColExpr->op==TK_DOT ){
         pColExpr = pColExpr->pRight;
         assert( pColExpr!=0 );
       }

src/where.c

@@ -235,6 +235,16 @@ static void createMask(WhereMaskSet *pMaskSet, int iCursor){
   pMaskSet->ix[pMaskSet->n++] = iCursor;
 }
 
+/*
+** If the right-hand branch of the expression is a TK_COLUMN, then return
+** a pointer to the right-hand branch.  Otherwise, return NULL.
+*/
+static Expr *whereRightSubexprIsColumn(Expr *p){
+  p = sqlite3ExprSkipCollateAndLikely(p->pRight);
+  if( ALWAYS(p!=0) && p->op==TK_COLUMN ) return p;
+  return 0;
+}
+
 /*
 ** Advance to the next WhereTerm that matches according to the criteria
 ** established when the pScan object was initialized by whereScanInit().
@@ -265,8 +275,7 @@ static WhereTerm *whereScanNext(WhereScan *pScan){
         ){
           if( (pTerm->eOperator & WO_EQUIV)!=0
            && pScan->nEquiv<ArraySize(pScan->aiCur)
-           && (pX = sqlite3ExprSkipCollateAndLikely(pTerm->pExpr->pRight))->op
+           && (pX = whereRightSubexprIsColumn(pTerm->pExpr))!=0
-               ==TK_COLUMN
           ){
             int j;
             for(j=0; j<pScan->nEquiv; j++){
@@ -462,7 +471,8 @@ static int findIndexCol(
 
   for(i=0; i<pList->nExpr; i++){
     Expr *p = sqlite3ExprSkipCollateAndLikely(pList->a[i].pExpr);
-    if( p->op==TK_COLUMN
+    if( ALWAYS(p!=0)
+     && p->op==TK_COLUMN
      && p->iColumn==pIdx->aiColumn[iCol]
      && p->iTable==iBase
     ){
@@ -526,6 +536,7 @@ static int isDistinctRedundant(
   */
   for(i=0; i<pDistinct->nExpr; i++){
     Expr *p = sqlite3ExprSkipCollateAndLikely(pDistinct->a[i].pExpr);
+    if( NEVER(p==0) ) continue;
     if( p->op==TK_COLUMN && p->iTable==iBase && p->iColumn<0 ) return 1;
   }
 
@@ -2811,6 +2822,7 @@ static int indexMightHelpWithOrderBy(
   if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
   for(ii=0; ii<pOB->nExpr; ii++){
     Expr *pExpr = sqlite3ExprSkipCollateAndLikely(pOB->a[ii].pExpr);
+    if( NEVER(pExpr==0) ) continue;
     if( pExpr->op==TK_COLUMN && pExpr->iTable==iCursor ){
       if( pExpr->iColumn<0 ) return 1;
       for(jj=0; jj<pIndex->nKeyCol; jj++){
@@ -3789,6 +3801,7 @@ static i8 wherePathSatisfiesOrderBy(
     for(i=0; i<nOrderBy; i++){
       if( MASKBIT(i) & obSat ) continue;
       pOBExpr = sqlite3ExprSkipCollateAndLikely(pOrderBy->a[i].pExpr);
+      if( NEVER(pOBExpr==0) ) continue;
       if( pOBExpr->op!=TK_COLUMN ) continue;
       if( pOBExpr->iTable!=iCur ) continue;
       pTerm = sqlite3WhereFindTerm(&pWInfo->sWC, iCur, pOBExpr->iColumn,
@@ -3915,6 +3928,7 @@ static i8 wherePathSatisfiesOrderBy(
           pOBExpr = sqlite3ExprSkipCollateAndLikely(pOrderBy->a[i].pExpr);
           testcase( wctrlFlags & WHERE_GROUPBY );
           testcase( wctrlFlags & WHERE_DISTINCTBY );
+          if( NEVER(pOBExpr==0) ) continue;
           if( (wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY))==0 ) bOnce = 0;
           if( iColumn>=XN_ROWID ){
             if( pOBExpr->op!=TK_COLUMN ) continue;

src/whereexpr.c

@@ -1451,6 +1451,7 @@ static void exprAnalyze(
 void sqlite3WhereSplit(WhereClause *pWC, Expr *pExpr, u8 op){
   Expr *pE2 = sqlite3ExprSkipCollateAndLikely(pExpr);
   pWC->op = op;
+  assert( pE2!=0 || pExpr==0 );
   if( pE2==0 ) return;
   if( pE2->op!=op ){
     whereClauseInsert(pWC, pExpr, 0);