QgsZonalStatistics.calculateStatistics() incomplete outputs

[nicogodet]

Describe the bug
Input:

QgsZonalStatistics.calculateStatistics(
  raster.dataProvider(),
  feat.geometry(),
  raster.rasterUnitsPerPixelX(),
  raster.rasterUnitsPerPixelY(),
  1,
  QgsZonalStatistics.Statistic.All
)

Output:

{0: 6.324437375868002}

The dictionary only contains Variance.
Since I specify QgsZonalStatistics.Statistic.All, output should contains all stats.

If I pass a specific stat like QgsZonalStatistics.Statistic.Mean or QgsZonalStatistics.Statistic.Median, the output is correct.
If I build the argument to contain only 2 stats, output is wrong again and contains the only the last stat listed in All.
All = Count | Sum | Mean | Median | StDev | Max | Min | Range | Minority | Majority | Variety | Variance
Mix of Mean and Median will return Median, Median and Max return Max, ...
Examples:
Input:

stats = QgsZonalStatistics.Statistic(QgsZonalStatistics.Statistic.Median | QgsZonalStatistics.Statistic.Mean)
# Both
QgsZonalStatistics.calculateStatistics(
  raster.dataProvider(),
  feat.geometry(),
  raster.rasterUnitsPerPixelX(),
  raster.rasterUnitsPerPixelY(),
  1,
  stats
)
# Only Median
QgsZonalStatistics.calculateStatistics(
  raster.dataProvider(),
  feat.geometry(),
  raster.rasterUnitsPerPixelX(),
  raster.rasterUnitsPerPixelY(),
  1,
  QgsZonalStatistics.Statistic.Median
)

Output:

# Both
{0: 4.880000114440918}
# Only median
{0: 4.880000114440918}

Input:

stats = QgsZonalStatistics.Statistic(QgsZonalStatistics.Statistic.Median | QgsZonalStatistics.Statistic.Max)
# Both
QgsZonalStatistics.calculateStatistics(
  raster.dataProvider(),
  feat.geometry(),
  raster.rasterUnitsPerPixelX(),
  raster.rasterUnitsPerPixelY(),
  1,
  stats
)
# Only Max
QgsZonalStatistics.calculateStatistics(
  raster.dataProvider(),
  feat.geometry(),
  raster.rasterUnitsPerPixelX(),
  raster.rasterUnitsPerPixelY(),
  1,
  QgsZonalStatistics.Statistic.Max
)

Output:

# Both
{0: 24.649999618530273}
# Only Max
{0: 24.649999618530273}

In addition, the key corresponds to nothing. It could be the integer set here : https://qgis.org/api/qgszonalstatistics_8h_source.html#l00051

[roya0045]

Is the OR operator truly the intended way to list things?

[nicogodet]

https://github.com/qgis/QGIS/blob/40988a8901bc746b4b5dc5601a01d03df1aafd65/src/analysis/processing/qgsalgorithmzonalstatisticsfeaturebased.cpp#L166L170

When the same function is called in a C++ script, it works fine.
But from Python, something fails...

[roya0045]

Possibly because they should be enum and python is not like c++ with stacking enums?

[nicogodet]

Or because QMap<QgsZonalStatistics::Statistic, QVariant> is not defined here : https://github.com/qgis/QGIS/blob/master/python/core/conversions.sip ?

Because stacking enums seems properly handled but it looks like the issue comes from the conversion from QMap to Dict