Unison developer here! Let's say you have some term:
B = "Hello "
and it hashes to #a3yx. Lets say you also have funcion:
A = B ++ "world" which hashes to #c7c1
when we store the A function, we actually store it as:
#c6c7 = #a3yx ++ "world"
Then later if you update the definition of B:
B = "Hello, "
and that function hashes to, #5e2b, when you tell unison to update B from #a3yx => #5e2b, it will look for all of the places that used to reference #a3yx, like your A function, and will see if those functions still typecheck with the replacement. If so, they are automatically updated. If not, we pretty print the definitions that didn't to a file for you to manually fix.
B = "Hello "
and it hashes to #a3yx. Lets say you also have funcion:
A = B ++ "world" which hashes to #c7c1
when we store the A function, we actually store it as:
#c6c7 = #a3yx ++ "world"
Then later if you update the definition of B:
B = "Hello, "
and that function hashes to, #5e2b, when you tell unison to update B from #a3yx => #5e2b, it will look for all of the places that used to reference #a3yx, like your A function, and will see if those functions still typecheck with the replacement. If so, they are automatically updated. If not, we pretty print the definitions that didn't to a file for you to manually fix.