Hello,
I've started using Gitflow Workflow as specified in https://www.atlassian.com/git/workflows#!workflow-gitflow.
Now I'm having issues with feedbacks and I'm not sure if I'm doing something wrong or is it the way it should be.
I borrowed graph from the link above and it looks like this.

Now suppose that we have two feature branches. First one which ends with commit A and second one which ends with commit B.
Suppose that there are some issues with feature B and it goes to next releases. In meantime there are few similar to A branches which ends merged into develop.
Branch develop has evolved because of my feature branches. That's why at some point my branch B can't be merged into develop.
It seems to me reasonable that pull request which has been opened on my feature branch should be mergeable before review is started.
I also think that developer which maintain branch B should leave it in mergeable state and it should be his responsibility to fix it since he has largest knowledge about implementation.
So there is a question are my assumptions wrong?
If not, there is next question. How can I bring my branch B to mergeable state?
I see two options:
A. merging upstream develop branch into my feature branch B
B. create new fresh version of feature branch B (let's call it B-v2) which base on upstream develop, after that merge branch B into B-v2 and resolve conflicts. (this solution was presented on some blog I've found)
About A option it looks like bad thing to me because in my pull request I have changesets which were merged from develop and has nothing in common with my feature.
About B option it seems to me that Stash was not created for this use case:
* I have to create new branch and merge old one into new one even if conflict is pretty simple
* I have to create new pull request on new branch
* I'm not able to delete old pull request (as stated here)
I would assume that pull request should evolve with feature. But with B option it looks impossible.
So I have that feeling that I'm doing something wrong. How this process should look like? What am I missing?