Changes to the struct update syntax

[Eiji]

@josevalim

The argument to deprecate the struct update syntax is to reduce the language surface.

Reasonable, but standalone not enough from DX experience.

@josevalim

While I believe the above is an improvement to Elixir v1.19.0-rc.0, as it forces people to pattern match before we potentially deprecate struct updates, we still need to decide if we want to deprecate the struct update syntax in v1.20 or later.

By default I prefer a flexibility in the code. However if there is a real value for a developer in exchange (as you have described) then it’s not just an another proposal, but a new good practice that’s better to be followed.

@josevalim

The main argument is that, if you have a long function, %User{user | ...} is a reminder and a type assertion of the type of the struct, while %{user | ...} would require you to keep more context in your head.

Let’s see it by example … I may not agree with some credo checks and they can even give sometimes a false-positives, but after some time I’ve realised that my code have much better quality. In theory I have forced myself to change a style, but in practice I’m more proud of my code than before and I believe that the best argument that could be raised.

So YES, please deprecate it!

Edit: Would there be any problem to ask for a patch release for db_connection and postgrex? I saw that you did that for ecto already:

v3.12.6 (2025-06-11)

Fix deprecations on Elixir v1.19.