v0.0.637 allow calling coll.Paginat() with limit=0 (to get only counts)

wmo/queryList.go

@@ -454,7 +454,7 @@ func createPaginationPipeline[TData any](coll *Coll[TData], token ct.CTKeySort,
 	} else if token.Mode == ct.CTMEnd {
 
 		// false
-		pipeline = append(pipeline, bson.D{{Key: "$match", Value: bson.M{"$expr": bson.M{"$eq": bson.A{"1", "0"}}}}})
+		pipeline = append(pipeline, bson.D{{Key: "$match", Value: PipelineNoMatch}})
 
 	} else {
 

wmo/queryPaginate.go

@@ -149,6 +149,10 @@ func (c *Coll[TData]) createPaginatedQuery(ctx context.Context, filter pag.Mongo
 	pipelineList := langext.ArrConcat(pipelineFilter, pipelineSort, pipelinePaginate, extrModPipelineResolved, pipelineSort)
 	pipelineTotalCount := langext.ArrConcat(pipelineFilter, pipelineCount)
 
+	if limit != nil && *limit <= 0 {
+		pipelineList = mongo.Pipeline{bson.D{{Key: "$match", Value: PipelineNoMatch}}} // always false | return nothing
+	}
+
 	cursorList, err := c.coll.Aggregate(ctx, pipelineList)
 	if err != nil {
 		return 0, nil, nil, exerr.Wrap(err, "mongo-aggregation failed").Any("pipeline", pipelineList).Str("collection", c.Name()).Build()

wmo/util.go

@@ -0,0 +1,10 @@
+package wmo
+
+import (
+	"git.blackforestbytes.com/BlackForestBytes/goext/langext"
+	"go.mongodb.org/mongo-driver/v2/bson"
+)
+
+var ObjectIDZero = langext.Must(bson.ObjectIDFromHex("000000000000000000000000"))
+
+var PipelineNoMatch = bson.M{"_id": ObjectIDZero, "$expr": bson.M{"$eq": bson.A{"1", "0"}}} // always false | returns nothing