The most common and most likely answer to this crossword clue is the 8 letter word ROOMMATE
I've seen this crossword clue in Financial Times
R
O
O
M
M
A
T
E
Buddy explains!

The straight part
We know that "one sharing digs" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one sharing digs = roommate.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ROOMMATE mean?
ROOMMATE noun- A person with whom one shares a room, as at university etc.
- A person (UK: flatmate, housemate, AU: sharemate) sharing the same home (sharehome).