Rename SQLITE_FUNC_VARYING to SQLITE_FUNC_SLOCHNG - a more descriptive name

for what that bit means.

FossilOrigin-Name: ff5137a6dd8cb2a9b629b3a244f52665e9c9ebce

2 files changed, 10 insertions, 8 deletions

diff --git a/src/resolve.c b/src/resolve.c
index 9522f63ce..22df22394 100644
--- a/src/resolve.c
+++ b/src/resolve.c
@@ -729,15 +729,16 @@ static int resolveExprStep(Walker *pWalker, Expr *pExpr){
           return WRC_Prune;
         }
 #endif
-        if( pDef->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_VARYING) ){
+        if( pDef->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG) ){
           /* For the purposes of the EP_ConstFunc flag, date and time
           ** functions and other functions that change slowly are considered
           ** constant because they are constant for the duration of one query */
           ExprSetProperty(pExpr,EP_ConstFunc);
         }
         if( (pDef->funcFlags & SQLITE_FUNC_CONSTANT)==0 ){
-          /* DATETIME functions are considered non-deterministic because of
-          ** the 'now' capability */
+          /* Date/time functions that use 'now', and other functions like
+          ** sqlite_version() that might change over time cannot be used
+          ** in an index. */
           notValid(pParse, pNC, "non-deterministic functions", NC_IdxExpr);
         }
       }
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 8bbb91332..69315ed46 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1396,7 +1396,8 @@ struct FuncDestructor {
 #define SQLITE_FUNC_UNLIKELY 0x0400 /* Built-in unlikely() function */
 #define SQLITE_FUNC_CONSTANT 0x0800 /* Constant inputs give a constant output */
 #define SQLITE_FUNC_MINMAX   0x1000 /* True for min() and max() aggregates */
-#define SQLITE_FUNC_VARYING  0x2000 /* Function that change in the long term */
+#define SQLITE_FUNC_SLOCHNG  0x2000 /* "Slow Change". Value constant during a
+                                    ** single query - might change over time */
 
 /*
 ** The following three macros, FUNCTION(), LIKEFUNC() and AGGREGATE() are
@@ -1414,7 +1415,7 @@ struct FuncDestructor {
 **
 **   DFUNCTION(zName, nArg, iArg, bNC, xFunc)
 **     Like FUNCTION except it omits the SQLITE_FUNC_CONSTANT flag and
-**     adds the SQLITE_FUNC_VARYING flag.  Used for date & time functions
+**     adds the SQLITE_FUNC_SLOCHNG flag.  Used for date & time functions
 **     and functions like sqlite_version() that can change, but not during
 **     a single query.
 **
@@ -1439,13 +1440,13 @@ struct FuncDestructor {
   {nArg, SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
    SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0, 0}
 #define DFUNCTION(zName, nArg, iArg, bNC, xFunc) \
-  {nArg, SQLITE_FUNC_VARYING|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
+  {nArg, SQLITE_FUNC_SLOCHNG|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
    SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0, 0}
 #define FUNCTION2(zName, nArg, iArg, bNC, xFunc, extraFlags) \
   {nArg,SQLITE_FUNC_CONSTANT|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL)|extraFlags,\
    SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0, 0}
 #define STR_FUNCTION(zName, nArg, pArg, bNC, xFunc) \
-  {nArg, SQLITE_FUNC_VARYING|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
+  {nArg, SQLITE_FUNC_SLOCHNG|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
    pArg, 0, xFunc, 0, 0, #zName, 0, 0}
 #define LIKEFUNC(zName, nArg, arg, flags) \
   {nArg, SQLITE_FUNC_CONSTANT|SQLITE_UTF8|flags, \
@@ -2131,7 +2132,7 @@ struct Expr {
 #define EP_MemToken  0x010000 /* Need to sqlite3DbFree() Expr.zToken */
 #define EP_NoReduce  0x020000 /* Cannot EXPRDUP_REDUCE this Expr */
 #define EP_Unlikely  0x040000 /* unlikely() or likelihood() function */
-#define EP_ConstFunc 0x080000 /* A SQLITE_FUNC_CONSTANT or _VARYING function */
+#define EP_ConstFunc 0x080000 /* A SQLITE_FUNC_CONSTANT or _SLOCHNG function */
 #define EP_CanBeNull 0x100000 /* Can be null despite NOT NULL constraint */
 #define EP_Subquery  0x200000 /* Tree contains a TK_SELECT operator */