For the Boys (1991)
Only rings half the bell: ex-spouses. Don't remember auditions and/or troops performing.
Hey, Rookie (1944)
He's organizing the show, and she's gonna get in...
Can you remember which war? WWI, WWII, Korea, Vietnam, later?
If it was an American musical (meaning it was financed by American sources), I have a list of those. Here's a link to them with the requirement they also have genre War (which your film may not have; remember IMDb is built by contributors, and when I watched a slew of musicals from Sept2017-Mar2019, I rarely checked if it had enough genres.)
https://www.imdb.com/list/ls021062047/?sort=list_order,asc&st_dt=&mode=detail&page=1&...For instance, I don't see on this subset of War genre Music/als the film
Tonight and Every Night (1945)
which is definitely a war film (London is being bombed, people die.) Nor is the 1991 film I started this post with.
You can use the Refine feature to turn off the War restriction, and/or add others.
Restricting with Keywords might help, but again, keywords are user-contributed, so may be absent in the most obvious of cases.
If the film might have been British, you can edit the search shown in the description, replacing &countries=us with &countries=gb.