A non-local extension of the shear-modified Gurson model for porous plasticity is proposed, which is capable of preventing spurious strain localization and suitable for predicting crack initiation and growth under general loading conditions. In the extended model, the progression of shear failure is separated from flat dimple rupture by the assumption that these failure mechanisms are characterized by a deviatoric and a dilatational material length parameter, respectively. The two length parameters are introduced through a delocalization process based on the non-local integral approach evaluated on the current configuration. A comprehensive numerical investigation is conducted to disclose the influence of these length parameters. For this purpose, five different specimen geometries are considered covering a wide range of stress triaxialities including pure shear. It is observed that separation of the length parameters is essential for predicting crack branching driven by shear localization, e.g., the flat dimple-to-shear failure transition of a crack that approaches and penetrates a free surface.