[gdal-dev] FileGDBs and FIDs of -21121

[Even Rouault]

oh, I've managed to reproduce. This is a bug in the OpenFileGDB driver. 
Fix to follow soon

Le 27/08/2024 à 22:31, Seth G a écrit :
> Thanks Even for the details.
>
> Sorry, the FID is correctly populated (with an autogenerated FID values starting from 1). However the unique ID of the feature is exported in a separate attribute field, and it is in this field that all values are present in the FileGDB except for the record with -21121:
>
> FID UniqueId
> 1      -21119
> 2     -21120
> 3     NULL (this should be -21121)
> ...
>
> Looks like this could be a MapServer rather than GDAL issue so I'll debug further,
>
> Seth
>
> --
> web:https://geographika.net & https://mapserverstudio.net
> twitter: @geographika
>
> On Tue, Aug 27, 2024, at 10:03 PM, Even Rouault wrote:
>> Seth,
>>
>> I'm not totally sure to understand the exact scenario. -21121 is a
>> special value for OGRField, which is a distinct concept that the Feature
>> ID, and normally it shouldn't prevent setting Integer64 fields to the
>> value as this canary is set in 2 fields of OGRField.
>>
>> from osgeo import ogr
>> layer_defn = ogr.FeatureDefn("test")
>> layer_defn.AddField(ogr.FieldDefn("i64", ogr.OFTInteger64))
>>    layer_defn.AddFieldDefn(ogr.FieldDefn("i64", ogr.OFTInteger64))
>> f = ogr.Feature(layer_defn)
>> f["i64"] = -21121
>> f.DumpReadable()
>> OGRFeature(test):-1
>>     i64 (Integer64) = -21121
>>
>> But what is sure is that the OpenFileGDB driver will error out if you
>> pass to CreateFeature() a feature with a FID < -1,  = 0 or > INT32_MAX,
>> since the FileGDB format only supports FID in the range [1, INT32_MAX],
>> and -1 is the OGRNullFID special constant to indicate that you let the
>> driver automatically assign a FID.
>>
>> With GeoJSON, you would likely have an issue with features of FID = -1
>> which would get assign a FID by the driver. Basically most formats will
>> struggle with negative or null FIDs
>>
>> What is perhaps missing in MapServer is a FORMATOPTION "SET_FID=FALSE"
>> for drivers such as FileGDB  (or "FID_VALID_MIN" and "FIX_VALID_MAX" ?)
>> to limit the scope of calls to OGR_F_SetFID() by MapServer.
>>
>> Even
>>
>>
>> Le 27/08/2024 à 21:32, Seth G via gdal-dev a écrit :
>>> Hi all,
>>>
>>> I'm using a GDAL within MapServer to export features as a FileGDB. Using the following OUTPUTFORMAT:
>>>
>>>       OUTPUTFORMAT
>>>           NAME "FileGDB"
>>>           DRIVER "OGR/OpenFileGDB"
>>>           MIMETYPE "application/x-ogc­filegdb"
>>>           FORMATOPTION "STORAGE=filesystem"
>>>           FORMATOPTION "FORM=zip"
>>>           FORMATOPTION "FILENAME=result.gdb.zip"
>>>           FORMATOPTION "LCO:FID=FID"
>>>       END
>>>
>>> I ran into an issue where a single feature Id is being set to NULL. After checking various database queries and configs it looks like the issue is when a feature id is -21121 and data exported to a FileGDB. When using GeoJSON the Id is returned correctly.
>>>
>>> I searched in the GDAL codebase and found that this is a "magic" number: https://github.com/search?q=repo%3AOSGeo%2Fgdal%20-21121&type=code
>>>
>>> #define OGRUnsetMarker -21121
>>>
>>> Is there any way round this other than using different Ids?
>>>
>>> Thanks,
>>>
>>> Seth
>>>
>>>
>>>
>>> --
>>> web:https://geographika.net & https://mapserverstudio.net
>>> twitter: @geographika
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