This question is related to, but different from Homebrew install specific version of formula? (since that question deals with different versions of the formula, while I'm taking about the --HEAD installs with the same formula but a different commit).
I often install nightly versions of the fish shell with brew install fish --HEAD, see also https://github.com/fish-shell/fish-shell/wiki/Development-builds#macos.
I recently found a regression and I'd like to install a two-week-old nightly version of fish in the same way. In other words, I'd like to do exactly the same procedure as brew install --HEAD, but using a specific commit in the fish-shell repo instead of today's master branch commit.
Is this possible with Homebrew?