Oh wow, I totally forgot about that thread from last year. There was some more discussion [1], a PR with reference implementation of this change [2] and even a PR in the wild that this change would have caught [3]. Thank you for linking to it!
[1] https://github.com/elixir-lang/elixir/issues/11331 [2] https://github.com/elixir-lang/elixir/pull/11333 [3] https://github.com/phoenixframework/phoenix/pull/4559/files > On 16 Aug 2022, at 13:19, Sabiwara Yukichi <sabiw...@gmail.com> wrote: > > It seems really close to this discussion: > https://groups.google.com/g/elixir-lang-core/c/1wixK5zNBEw/m/FVNpANbPBQAJ > <https://groups.google.com/g/elixir-lang-core/c/1wixK5zNBEw/m/FVNpANbPBQAJ>. > > I don't think this would solve the issue completely though: should we then > warn for nested maps like `[%{}] =` or `{:ok, %{}} =`? (which might be > intended) > Also, people might be writing `%{name: "foo"} =` actually meaning `%{name: > "foo"} ==`, but I don't think we should warn on these. > > > my recommendation is to always do `assert actual == expected` and `assert > > expected = actual`, never `assert expected == actual` > > I really like this suggestion you made in the previous thread, it helps a lot > distinguishing between matches and equality, maybe it could be encouraged in > the official docs? > > > > Le mar. 16 août 2022 à 19:17, Wojtek Mach <woj...@wojtekmach.pl > <mailto:woj...@wojtekmach.pl>> a écrit : > Just to be clear what I proposed was not a change in the compiler, just > changing ExUnit's assert macro to emit the warning under that specific > scenario. > >> On 16 Aug 2022, at 11:59, Ben Wilson <benwilson...@gmail.com >> <mailto:benwilson...@gmail.com>> wrote: >> >> To me this feels like a good use of credo or similar linter, not something >> that the Elixir compiler itself should warn about. `assert %{} = x` isn't >> the most idiomatic way to match but it isn't incoherent or invalid, just >> probably not best practice. >> >> On Tuesday, August 16, 2022 at 5:55:09 AM UTC-4 woj...@wojtekmach.pl >> <mailto:woj...@wojtekmach.pl> wrote: >> Hi, >> >> Developers can easily shoot themselves in the foot if they write: >> >> assert %{} = x >> >> but really what they meant was to write: >> >> assert %{} == x >> >> The mistake is writing `=` instead of `==`, an easy one to make. The >> difference is of course that the former will succeed on _any_ map and the >> latter will _only_ succeed on an _empty_ map. >> >> I'd like to propose ExUnit warn on `assert %{} = x` and tell users to >> instead write `assert is_map(x)`. >> >> Thoughts? >> >> P.S. In my projects I'd either write `assert actual == expected` OR `assert >> expected = actual` and never `assert expected == actual` exactly because it >> is easy to make the mistake. Maybe there is a Credo check to enforce such >> style. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "elixir-lang-core" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to elixir-lang-core+unsubscr...@googlegroups.com >> <mailto:elixir-lang-core+unsubscr...@googlegroups.com>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/elixir-lang-core/b70a4bb4-14d4-4ea3-8b49-45b408abf750n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/elixir-lang-core/b70a4bb4-14d4-4ea3-8b49-45b408abf750n%40googlegroups.com?utm_medium=email&utm_source=footer>. > > > -- > You received this message because you are subscribed to the Google Groups > "elixir-lang-core" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to elixir-lang-core+unsubscr...@googlegroups.com > <mailto:elixir-lang-core+unsubscr...@googlegroups.com>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elixir-lang-core/D3AD3ABD-1F0F-48F8-B9C2-A3E6B67E8EB1%40wojtekmach.pl > > <https://groups.google.com/d/msgid/elixir-lang-core/D3AD3ABD-1F0F-48F8-B9C2-A3E6B67E8EB1%40wojtekmach.pl?utm_medium=email&utm_source=footer>. > > -- > You received this message because you are subscribed to the Google Groups > "elixir-lang-core" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to elixir-lang-core+unsubscr...@googlegroups.com > <mailto:elixir-lang-core+unsubscr...@googlegroups.com>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elixir-lang-core/CANnyohY3LT826R%3D3h%3DNhhNMjias-LKfUuHRhpnL_SQxMDvxiag%40mail.gmail.com > > <https://groups.google.com/d/msgid/elixir-lang-core/CANnyohY3LT826R%3D3h%3DNhhNMjias-LKfUuHRhpnL_SQxMDvxiag%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. To unsubscribe from this group and stop receiving emails from it, send an email to elixir-lang-core+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/elixir-lang-core/8168110E-341A-4C3E-89AE-7AC92ACBEC82%40wojtekmach.pl.
