Okay. Stayed up to early but I got through this. Sparing you the detail of my test log, I set up two sites that were identical except one was called site1 and the other site2 (directory, database name, site name in WP) and they treated Roots differently (something for my own workflow/process testing). Everything was taken from master branches in my local clone repos. The master branches are clean clones from Github forks.
After setting up the directories from the WordPress-Skeleton repo and the Roots repo, but before installing WordPress or running npm install for Roots, I did the following.
Check site1, site2 for .htaccess in site root and site1/wp, site2/wp.
(site1 root: .htaccess 9/6, 12:14, site1/wp: no .htaccess)
(site2 root: .htaccess 9/6, 12:21, site1/wp: no .htaccess)
I checked frequently during the process and that’s how it stayed until…
Site1: Activate Roots, yes to the five questions.
Check site1 for .htaccess in site root and site1/wp.
(site1 root: .htaccess 9/6, 12:14, site1/wp: .htaccess 9/6 1:11)
Site1: navigate to Settings, Permalinks. Click Save Changes.
Check site1 for .htaccess in site root and site1/wp.
(site1 root: .htaccess 9/6, 12:14, site1/wp: .htaccess 9/6 1:13)
Site2: Activate Roots, yes to the five questions.
Check site2 for .htaccess in site root and site2/wp.
(site2 root: .htaccess 9/6, 12:21, site1/wp: .htaccess 9/6 1:14)
Site2: navigate to Settings, Permalinks. Click Save Changes.
Check site2 for .htaccess in site root and site2/wp.
(site2 root: .htaccess 9/6, 12:21, site1/wp: .htaccess 9/6 1:17)
Note that I checked .htaccess immediately before activating Roots in both themes and it was the same as the first check.
Based on this, both activating Roots (which sets permalinks and other rewrites in .htaccess) and saving permalink settings WordPress (which sets permalink rewrites in .htaccess) are writing .htaccess to the wp submodule. I’m going to suggest maybe that’s how it’s supposed to be.
Backing up this theory, I use a GUI tool for git and can inspect the changes in the wp submodule. The only change git detects is in .htaccess (for rewrites). There is no .gitignore in the wp submodule, so git should report any other changes.