Changing colours in Scatter Plot from table does not work

[Hrovatin]

When setting colours in Scatter Plot using data from Table the colour in scatter plot does not change.

To Reproduce

For example: gbfA_avg is plotted (selected as attribute in Table) and colour is set to red in Colour widget, but this is not reproduced in Scatter Plot.

Orange version:
3.24
Operating system:
Ubuntu

[janezd]

Not a duplicate, yet a close relative of #3944. Domain.__hash__ relies on Variable.__hash__, which is just ordinary hash (based on instance id) and does not reflect changes of a variable instance.

There's no point in fixing this now because in #3925 (assuming it will be merged), Variable.__hash__ sums the hash of name, type and compute_value. We should add colors, and -- @Hrovatin thanks for reporting this and reminding us! -- DiscreteVariable.__hash__ must also include values for DiscreteVariable otherwise #3944 will reappear.

[janezd]

I can no longer reproduce this after we removed Variable.make and after fixes in #4041.

@Hrovatin, apologies for wasting your time with dysfunctional Color widget on Friday. Can you try with #4041 (when you're back to work)?

@VesnaT, I don't know what fixed it -- and I don't like this. The Color widget now constructs a new Variable on every change, but this Variable should be considered equal to the previous because color is not (and must not be) included in __hash__ and __eq__. If plot update is nevertheless triggered, it may be prudent to check whether there are any situations in which it is triggered although it shouldn't be. Please check it when/if you have time.

[VesnaT]

Nothing fixed it - it was never an issue. Even though the data does not change (i. e. self._invalidated = False), the points properties are still updated (check handleNewSignals() in OWDataProjectionWidget).

The problem this issue addresses is changing a color for a variable with more than 10 values. The variable's values are then shown as 10 most common values plus Other (with a different color palette). Replacing the palette covers up the color change.

[VesnaT]

Speaking of Variable's __hash__ and __eq__: Shouldn't they consider self.attributes somehow? I know dictionary is not hashable, but how can two variables with different attributes be equal.

[janezd]

So this issue can be closed?

As for __hash__ and attributes: it boils down to definition of equality. Two discrete variables can now be equal even though they have different values. What matters is name, type and compute_value. I was confused on Friday when I said we have to check other things, too. This should be a good definition in general, though in some places we'll need to check for "deeper" equality.