v0.0.437 properly handle $group in wmo extraModPipeline

wmo/collection.go

@@ -125,3 +125,17 @@ func (c *Coll[TData]) createToken(fieldPrimary string, dirPrimary ct.SortDirecti
 		Extra:          ct.Extra{},
 	}, nil
 }
+
+func (c *Coll[TData]) needsDoubleSort(ctx context.Context) bool {
+	for _, ppl := range c.extraModPipeline {
+		for _, stage := range ppl(ctx) {
+			for _, bsone := range stage {
+				if bsone.Key == "$group" {
+					// a group stage in extraModPipeline results in unsorted data, which means the caller must sort again after these pipeline stages...
+					return true
+				}
+			}
+		}
+	}
+	return false
+}

wmo/queryFind.go

@@ -36,6 +36,14 @@ func (c *Coll[TData]) Find(ctx context.Context, filter bson.M, opts ...*options.
 		pipeline = langext.ArrConcat(pipeline, ppl(ctx))
 	}
 
+	if c.needsDoubleSort(ctx) {
+		for _, opt := range opts {
+			if opt != nil && opt.Sort != nil {
+				pipeline = append(pipeline, bson.D{{Key: "$sort", Value: opt.Sort}})
+			}
+		}
+	}
+
 	for _, opt := range opts {
 		if opt != nil && opt.Projection != nil {
 			pipeline = append(pipeline, bson.D{{Key: "$project", Value: opt.Projection}})

wmo/queryList.go

@@ -35,7 +35,7 @@ func (c *Coll[TData]) List(ctx context.Context, filter ct.Filter, pageSize *int,
 		sortDirSecondary = nil
 	}
 
-	paginationPipeline, err := createPaginationPipeline(c, inTok, sortPrimary, sortDirPrimary, sortSecondary, sortDirSecondary, pageSize)
+	paginationPipeline, doubleSortPipeline, err := createPaginationPipeline(c, inTok, sortPrimary, sortDirPrimary, sortSecondary, sortDirSecondary, pageSize)
 	if err != nil {
 		return nil, ct.CursorToken{}, exerr.
 			Wrap(err, "failed to create pagination").
@@ -56,6 +56,10 @@ func (c *Coll[TData]) List(ctx context.Context, filter ct.Filter, pageSize *int,
 		pipeline = langext.ArrConcat(pipeline, ppl(ctx))
 	}
 
+	if c.needsDoubleSort(ctx) {
+		pipeline = langext.ArrConcat(pipeline, doubleSortPipeline)
+	}
+
 	cursor, err := c.coll.Aggregate(ctx, pipeline)
 	if err != nil {
 		return nil, ct.CursorToken{}, exerr.Wrap(err, "mongo-aggregation failed").Any("pipeline", pipeline).Str("collection", c.Name()).Build()
@@ -136,14 +140,14 @@ func (c *Coll[TData]) ListWithCount(ctx context.Context, filter ct.Filter, pageS
 	return data, token, count, nil
 }
 
-func createPaginationPipeline[TData any](coll *Coll[TData], token ct.CursorToken, fieldPrimary string, sortPrimary ct.SortDirection, fieldSecondary *string, sortSecondary *ct.SortDirection, pageSize *int) ([]bson.D, error) {
+func createPaginationPipeline[TData any](coll *Coll[TData], token ct.CursorToken, fieldPrimary string, sortPrimary ct.SortDirection, fieldSecondary *string, sortSecondary *ct.SortDirection, pageSize *int) ([]bson.D, []bson.D, error) {
 
 	cond := bson.A{}
 	sort := bson.D{}
 
 	valuePrimary, err := coll.getTokenValueAsMongoType(token.ValuePrimary, fieldPrimary)
 	if err != nil {
-		return nil, exerr.Wrap(err, "failed to get (primary) token-value as mongo-type").Build()
+		return nil, nil, exerr.Wrap(err, "failed to get (primary) token-value as mongo-type").Build()
 	}
 
 	if sortPrimary == ct.SortASC {
@@ -160,7 +164,7 @@ func createPaginationPipeline[TData any](coll *Coll[TData], token ct.CursorToken
 
 		valueSecondary, err := coll.getTokenValueAsMongoType(token.ValueSecondary, *fieldSecondary)
 		if err != nil {
-			return nil, exerr.Wrap(err, "failed to get (secondary) token-value as mongo-type").Build()
+			return nil, nil, exerr.Wrap(err, "failed to get (secondary) token-value as mongo-type").Build()
 		}
 
 		if *sortSecondary == ct.SortASC {
@@ -203,15 +207,17 @@ func createPaginationPipeline[TData any](coll *Coll[TData], token ct.CursorToken
 
 	} else {
 
-		return nil, exerr.New(exerr.TypeInternal, "unknown ct mode: "+string(token.Mode)).Any("token.Mode", token.Mode).Build()
+		return nil, nil, exerr.New(exerr.TypeInternal, "unknown ct mode: "+string(token.Mode)).Any("token.Mode", token.Mode).Build()
 
 	}
 
 	pipeline = append(pipeline, bson.D{{Key: "$sort", Value: sort}})
 
+	pipelineSort := mongo.Pipeline{bson.D{{Key: "$sort", Value: sort}}}
+
 	if pageSize != nil {
 		pipeline = append(pipeline, bson.D{{Key: "$limit", Value: int64(*pageSize + 1)}})
 	}
 
-	return pipeline, nil
+	return pipeline, pipelineSort, nil
 }