I m like 99 certain that this is the case but I m just looki

Question

I m like 99 certain that this is the case but I m just looking to confirm when I have a task that creates a piece of mutable data say a dictionary and I pass it downstream to two different tasks both tasks get a reference to the original dict right So if one task edits it there risk for conflict ex ```with Flow foo as f a = task lambda x key x value b = task lambda y y pop key a c = task lambda z z get key a ```

Anna Geller · Answer

no risk under the hood Prefect creates a copy of a task and passes the same a data dependency to both b and c you can see it well when you visualize the flow

Anna Geller · Answer

if you want to be 100 about anything don t take my word for it but instead test it out run it print the data and you ll be then 100 sure smile

kevin · Answer

hmm yea i tried altering the flow to look like this ```with Flow foo as f a = task lambda x key x value b = task lambda y y pop key a c = task lambda z z key a ``` and I get a KeyError when it hits `c`

kevin · Answer

it seems like the reference object is shared between the two tasks

Kevin Kho · Answer

That is news to me but I can also believe it you could wrap the lambda input into a deepcopy to be sure this works right

kevin · Answer

for task c

Kevin Kho · Answer

```with Flow foo as f a = task lambda x key x value b = task lambda y deepcopy y pop key a c = task lambda z z key a ```

Kevin Kho · Answer

Like that I dunno not sure

kevin · Answer

yea that gave me all tasks succeeded

kevin · Answer

we re on a pretty old version of prefect ` ==0 14 14 `

kevin · Answer

if that changes anything

Kevin Kho · Answer

I dont think the prefect version will affect this I think it s just the execution creates a dict which is mutable and it just gets updated instead of copies created

kevin · Answer

yea it seems pythonically reasonable to have that be the case