Background / current role:
I'm a software engineer and I've been working almost alone on a project which has an impact on the whole company (big company 10,000+ employees). The project has been resumed after a few years of inactivity with plenty of tech debt. It's extremely hard to do estimations because almost daily I discover something bad which delays me.
Two months ago I asked my manager if somebody else could help me on this project, and my manager assigned another engineer to this project. Then he asked me for estimations and it was estimated that this project would be completed in mid January (with 2.5 people assigned).
In practice this very talented engineer in the last month has managed to work on this project only one week, due to being busy with some other tasks (manager knows about it).
My situation with the temporary internal role:
I just managed to get an informal offer for temporary position in a different department of my company -- the position will last until mid May next year.
Now, when I went to my manager to tell him that I would like to start with the temporary position in the other department he told me that he wants me to finish my project first.
The project isn't going smoothly both for its nature and lack of resources, so I doubt I'm going to complete it by mid January -- as things are now, February or March are a better guess.
My manager would like to keep me on this project until it's done. While the temporary position is only until mid May.
Also, if the start date is too late, they might not be interested in me anymore.
If anything goes wrong I'm very tempted to resign, but again the problem is that I would be still stuck in this role for the three months of notice. The relationship is definitely compromised.
I am looking for suggestions on how to proceed in this situation.
- My manager does not gain anything from me moving to the temp role;
- I'd like to stay with this company because every few months there are good positions available in other departments. Not too secondary for me, good company perks.