Combine buildSelectList into buildPropertyName

[LionelZoubritzky-IGN]

This PR merges the two existing implementations of select: one used to exist for the GpfGetFeatures codepath and another for GpfGetFeatureById. They are now grouped into buildPropertyName, which returns a propertyName with the following convention:

• propertyName is the empty string if and only if the caller is GpfCountFeatures.

• The geometry can be requested by two different causes:

  • either the tool is GpfGetFeaturesLayer or GpfGetFeatureByIdLayer, in which case it is always requested.
  • either the tool is GpfGetFeatures or GpfGetFeatureById, in which case it is requested if and only if spatial_extra is not empty.

  Be it one case or the other, when the geometry is requested, its name is resolved and included in propertyName. Otherwise, propertyName does not include the name of the geometry.

• Apart from the geometry, the rest of propertyName are the list of the selected properties. If select is undefined or empty, it is the list of all non-geometric properties of the typename in the catalog.

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When the name of the geometry is required, it is resolved by checking that there is a unique geometric property in the catalog. This name is required in two situations:

• Either the geometry is requested as part of the output of the request: this corresponds to the aforementioned cases, either a Layer tool or a non-empty spatial_extra
• Either the geometry name only is needed in order to build a CQL filter: this occurs when there is a spatial_filter in the query.

When the geometry name has been resolved, it is stored in the geometryProperty field of the CompiledQuery. It serves as a resolved cache, and also in the case where the catalog is desynced with the actual upstream WFS service: when this occurs and the required geometric property is absent from upstream, a dedicated error is thrown to identify this problem. The geometryProperty field of the CompiledQuery is used in this error, so this field needs to be populated whenever the geometry name is required, including when it is only used as part of a CQL filter (i.e. even if the geometry itself is not requested in the output).

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This PR also changes the behavior of requests on typenames that have either no or multiple geometries. Before, those used to throw an error on any request: now, they only throw an error if the geometry is required (spatial_filter / Layer tool / spatial_extra).

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Finally, rename attachFeatureRefs into postProcessFeatureCollection to more accurately reflect that this function handles all the post-processing, and does not only attach feature refs anymore.

[esgn]

The default parameter geometryProperty = getGeometryProperty(featureType) is evaluated whenever the argument is not provided, even when the geometry is not needed (no select, no spatial_extras). Yet getGeometryProperty throws on a type without any geometry property.

Consequence: a bare gpf_get_feature_by_id on wfs_scot:doc_urba or wfs_scot:doc_urba_com (the 2 geometry-less types in the embedded catalog) now fails before even issuing the WFS request, whereas it worked on main. The old buildPropertyName in byId.ts only resolved the geometry when necessary — that was the invariant documented by the comment removed along with the function.

[LionelZoubritzky-IGN]

Thank you for catching that regression! Addressed and tested in 25871c3

Additionally, when doing a GetFeatureById with empty select and spatial_extra, the query used to have an empty propertyName, which implies fetching the entire geometry, and then discarding it (and replacing it will null). The refactor already changed that, and the latest commit tests this case. It also add tests for the case of collection without geometries, like wfs_scot:doc_urba.

[esgn]

Have a look at gpf_get_features_layer { typename: "wfs_scot:doc_urba" } => I assume this will cause an error on the proxy side.

[LionelZoubritzky-IGN]

Good catch, thanks! Fixed in 65402f6
This surfaced another issue but I'm opening a separate PR for that: #185

[esgn]

First review

[esgn]

Second review