Replace TS_execute's TS_EXEC_CALC_NOT flag with TS_EXEC_SKIP_NOT.

It's fairly silly that ignoring NOT subexpressions is TS_execute's
default behavior.  It's wrong on its face and it encourages errors
of omission.  Moreover, the only two remaining callers that aren't
specifying CALC_NOT are in ts_headline calculations, and it's very
arguable that those are bugs: if you've specified "!foo" in your
query, why would you want to get a headline that includes "foo"?

Hence, rip that out and change the default behavior to be to calculate
NOT accurately.  As a concession to the slim chance that there is still
somebody somewhere who needs the incorrect behavior, provide a new
SKIP_NOT flag to explicitly request that.

Back-patch into v13, mainly because it seems better to change this
at the same time as the previous commit's rejiggering of TS_execute
related APIs.  Any outside callers affected by this change are
probably also affected by that one.

Discussion: https://postgr.es/m/CALT9ZEE-aLotzBg-pOp2GFTesGWVYzXA3=mZKzRDa_OKnLF7Mg@mail.gmail.com

src/backend/utils/adt/tsginidx.c

@@ -248,7 +248,7 @@ gin_tsquery_consistent(PG_FUNCTION_ARGS)
 
 		res = TS_execute(GETQUERY(query),
 						 &gcv,
-						 TS_EXEC_CALC_NOT | TS_EXEC_PHRASE_NO_POS,
+						 TS_EXEC_PHRASE_NO_POS,
 						 checkcondition_gin);
 	}
 
@@ -286,7 +286,7 @@ gin_tsquery_triconsistent(PG_FUNCTION_ARGS)
 
 		if (TS_execute(GETQUERY(query),
 					   &gcv,
-					   TS_EXEC_CALC_NOT | TS_EXEC_PHRASE_NO_POS,
+					   TS_EXEC_PHRASE_NO_POS,
 					   checkcondition_gin))
 			res = recheck ? GIN_MAYBE : GIN_TRUE;
 	}

src/backend/utils/adt/tsgistidx.c

@@ -348,7 +348,7 @@ gtsvector_consistent(PG_FUNCTION_ARGS)
 
 		PG_RETURN_BOOL(TS_execute(GETQUERY(query),
 								  key,
-								  TS_EXEC_PHRASE_NO_POS | TS_EXEC_CALC_NOT,
+								  TS_EXEC_PHRASE_NO_POS,
 								  checkcondition_bit));
 	}
 	else
@@ -359,7 +359,7 @@ gtsvector_consistent(PG_FUNCTION_ARGS)
 		chkval.arre = chkval.arrb + ARRNELEM(key);
 		PG_RETURN_BOOL(TS_execute(GETQUERY(query),
 								  (void *) &chkval,
-								  TS_EXEC_PHRASE_NO_POS | TS_EXEC_CALC_NOT,
+								  TS_EXEC_PHRASE_NO_POS,
 								  checkcondition_arr));
 	}
 }

src/backend/utils/adt/tsrank.c

@@ -697,7 +697,7 @@ Cover(DocRepresentation *doc, int len, QueryRepresentation *qr, CoverExt *ext)
 		fillQueryRepresentationData(qr, ptr);
 
 		if (TS_execute(GETQUERY(qr->query), (void *) qr,
-					   TS_EXEC_CALC_NOT, checkcondition_QueryOperand))
+					   TS_EXEC_EMPTY, checkcondition_QueryOperand))
 		{
 			if (WEP_GETPOS(ptr->pos) < ext->p)
 			{

src/backend/utils/adt/tsvector_op.c

@@ -1627,9 +1627,9 @@ TS_phrase_execute(QueryItem *curitem, void *arg, uint32 flags,
 			 * We need not touch data->width, since a NOT operation does not
 			 * change the match width.
 			 */
-			if (!(flags & TS_EXEC_CALC_NOT))
+			if (flags & TS_EXEC_SKIP_NOT)
 			{
-				/* without CALC_NOT, report NOT as "match everywhere" */
+				/* with SKIP_NOT, report NOT as "match everywhere" */
 				Assert(data->npos == 0 && !data->negate);
 				data->negate = true;
 				return TS_YES;
@@ -1875,7 +1875,7 @@ TS_execute_recurse(QueryItem *curitem, void *arg, uint32 flags,
 	switch (curitem->qoperator.oper)
 	{
 		case OP_NOT:
-			if (!(flags & TS_EXEC_CALC_NOT))
+			if (flags & TS_EXEC_SKIP_NOT)
 				return TS_YES;
 			switch (TS_execute_recurse(curitem + 1, arg, flags, chkcond))
 			{
@@ -2038,7 +2038,7 @@ ts_match_vq(PG_FUNCTION_ARGS)
 	chkval.operand = GETOPERAND(query);
 	result = TS_execute(GETQUERY(query),
 						&chkval,
-						TS_EXEC_CALC_NOT,
+						TS_EXEC_EMPTY,
 						checkcondition_str);
 
 	PG_FREE_IF_COPY(val, 0);

src/include/tsearch/ts_utils.h

@@ -183,10 +183,12 @@ typedef TSTernaryValue (*TSExecuteCallback) (void *arg, QueryOperand *val,
  */
 #define TS_EXEC_EMPTY			(0x00)
 /*
- * If TS_EXEC_CALC_NOT is not set, then NOT expressions are automatically
- * evaluated to be true.  Useful in cases where NOT isn't important (ranking).
+ * If TS_EXEC_SKIP_NOT is set, then NOT sub-expressions are automatically
+ * evaluated to be true.  This was formerly the default behavior.  It's now
+ * deprecated because it tends to give silly answers, but some applications
+ * might still have a use for it.
  */
-#define TS_EXEC_CALC_NOT		(0x01)
+#define TS_EXEC_SKIP_NOT		(0x01)
 /*
  * If TS_EXEC_PHRASE_NO_POS is set, allow OP_PHRASE to be executed lossily
  * in the absence of position information: a true result indicates that the