Question about dependecy resolution

[fernandocollova-endava]

Hi everyone! I'm working on a project with multiple branches, and I'm finding something funny when running my migrations...

I have a main branch that has the following revisions: A --> B --> C
And then a dev branch with B' --> C'

B' depends on B, and C' depends on C
And C has breaking changes that prevent you from running B' after it

Now, my expectation was that if I ran alembic upgrade dev@head I would get the following order of executions:

A --> B --> B' --> C --> C'

With the execution sort of jumping back and forth between the main and the dev branch following a sort of "chronological" order.

However, what I'm getting is

A --> B --> C --> B' --> C'

Is this the expected behavior? Is there anything I can do to get A --> B --> B' --> C --> C'?

Thanks, Fernando

[zzzeek]

if there's no relationship between C and B' then yes it's expected that these two migrations may occur in any order.

so if your migrations have an ordering requirement that C must occur after B', add this relationship using a dependency, that is, the depends_on label. see that documented section for examples, here you'd want to make C dependent on B'.

[fernandocollova-endava]

Works like a charm! I didn't get from the docs that this was the case, and reading them again, I don't think there is an example of this "crossed" dependency between branches... do you think I could contribute some docs for that? Or am I missing something (more 😅)?