Fix stale comments related to KeyInfo. Add new assert()s associated with

memory management of KeyInfo.

FossilOrigin-Name: abd805bc76f14ede7359b029908179b7ca57e929c5918acae1403ef73ae0bd47

3 files changed, 19 insertions, 16 deletions

diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 994a3864c..230646200 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -2644,9 +2644,10 @@ struct FKey {
 ** argument to sqlite3VdbeKeyCompare and is used to control the
 ** comparison of the two index keys.
 **
-** Note that aSortOrder[] and aColl[] have nField+1 slots.  There
-** are nField slots for the columns of an index then one extra slot
-** for the rowid at the end.
+** The aSortOrder[] and aColl[] arrays have nAllField slots each. There
+** are nKeyField slots for the columns of an index then extra slots
+** for the rowid or key at the end.  The aSortOrder array is located after
+** the aColl[] array.
 */
 struct KeyInfo {
   u32 nRef;           /* Number of references to this KeyInfo object */
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index a6798e62d..2d63654d0 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -4202,24 +4202,17 @@ void sqlite3VdbeSerialGet(
   return;
 }
 /*
-** This routine is used to allocate sufficient space for an UnpackedRecord
-** structure large enough to be used with sqlite3VdbeRecordUnpack() if
-** the first argument is a pointer to KeyInfo structure pKeyInfo.
+** Allocate sufficient space for an UnpackedRecord structure large enough
+** to hold a decoded index record for pKeyInfo.
 **
-** The space is either allocated using sqlite3DbMallocRaw() or from within
-** the unaligned buffer passed via the second and third arguments (presumably
-** stack space). If the former, then *ppFree is set to a pointer that should
-** be eventually freed by the caller using sqlite3DbFree(). Or, if the
-** allocation comes from the pSpace/szSpace buffer, *ppFree is set to NULL
-** before returning.
-**
-** If an OOM error occurs, NULL is returned.
+** The space is allocated using sqlite3DbMallocRaw().  If an OOM error
+** occurs, NULL is returned.
 */
 UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(
   KeyInfo *pKeyInfo               /* Description of the record */
 ){
   UnpackedRecord *p;              /* Unpacked record to return */
-  int nByte;                      /* Number of bytes required for *p */
+  u64 nByte;                      /* Number of bytes required for *p */
   assert( sizeof(UnpackedRecord) + sizeof(Mem)*65536 < 0x7fffffff );
   nByte = ROUND8P(sizeof(UnpackedRecord)) + sizeof(Mem)*(pKeyInfo->nKeyField+1);
   p = (UnpackedRecord *)sqlite3DbMallocRaw(pKeyInfo->db, nByte);
@@ -4250,6 +4243,7 @@ void sqlite3VdbeRecordUnpack(
   Mem *pMem = p->aMem;
 
   p->default_rc = 0;
+  assert( p->pKeyInfo==pKeyInfo );
   assert( EIGHT_BYTE_ALIGNMENT(pMem) );
   idx = getVarint32(aKey, szHdr);
   d = szHdr;
@@ -4275,6 +4269,8 @@ void sqlite3VdbeRecordUnpack(
     ** warnings from MSAN. */
     sqlite3VdbeMemSetNull(pMem-1);
   }
+  testcase( u == pKeyInfo->nKeyField + 1 );
+  testcase( u < pKeyInfo->nKeyField + 1 );
   assert( u<=pKeyInfo->nKeyField + 1 );
   p->nField = u;
 }
diff --git a/src/vdbesort.c b/src/vdbesort.c
index 6b1b4cff5..90ab28cd5 100644
--- a/src/vdbesort.c
+++ b/src/vdbesort.c
@@ -969,7 +969,8 @@ int sqlite3VdbeSorterInit(
   assert( pCsr->eCurType==CURTYPE_SORTER );
   assert( sizeof(KeyInfo) + UMXV(pCsr->pKeyInfo->nKeyField)*sizeof(CollSeq*)
                < 0x7fffffff );
-  szKeyInfo = SZ_KEYINFO(pCsr->pKeyInfo->nKeyField);
+  assert( pCsr->pKeyInfo->nKeyField<=pCsr->pKeyInfo->nAllField );
+  szKeyInfo = SZ_KEYINFO(pCsr->pKeyInfo->nAllField);
   sz = SZ_VDBESORTER(nWorker+1);
 
   pSorter = (VdbeSorter*)sqlite3DbMallocZero(db, sz + szKeyInfo);
@@ -983,7 +984,12 @@ int sqlite3VdbeSorterInit(
     pKeyInfo->db = 0;
     if( nField && nWorker==0 ){
       pKeyInfo->nKeyField = nField;
+      assert( nField<=pCsr->pKeyInfo->nAllField );
     }
+    /* It is OK that pKeyInfo reuses the aSortFlags field from pCsr->pKeyInfo,
+    ** since the pCsr->pKeyInfo->aSortFlags[] array is invariant and lives
+    ** longer that pSorter. */
+    assert( pKeyInfo->aSortFlags==pCsr->pKeyInfo->aSortFlags );
     sqlite3BtreeEnter(pBt);
     pSorter->pgsz = pgsz = sqlite3BtreeGetPageSize(pBt);
     sqlite3BtreeLeave(pBt);