On 15-10-2025 6:21, Theodore Brown wrote:
On Tue, October 14 2025 at 18:08 Juliette Reinders Folmer wrote:
Dear Theodore and list,
I've been looking into the "Deprecate semicolon after case in switch statement"
PHP 8.5 deprecation [1]
with the aim of adding a sniff for this to the PHPCompatibility standard and
I'm noticing an oddity for
which I would like to clarify whether this is intentional or an oversight.
As demonstrated in the example code provided in the deprecation RFC, both
switch `case` condition
statements, as well as `default` statements, can be ended with a semicolon.
So when I first read the RFC, I interpreted the proposal to include both `case`
as well as `default`,
as, in my mind, `default` is just a special `case` in a switch.
However, the RFC explicitly only talked about deprecating the use of a
semicolon after a
`case` statement and the implementation has followed this to the letter. [2]
The net result of this, is that you can now have a `switch` statement with
semicolons
terminating `case` statements and `default` statements, where the former
(`case`) will
result in a deprecation notice, while the latter (`default`) will not. For an
example, see [3]
This feels inconsistent to me and counter to the intention of the RFC, which is
stated to be:
Case statements followed by a semicolon can cause confusion, as a developer may
think they
behave differently in some way from regular case statements (e.g. preventing
fallthrough),
when they do not.
Which leaves me wondering what the reason was not to _also_ deprecate the use
of a semicolon
to terminate a `default` statement in a switch ? I can't find any discussion
about this in the
original mailing list thread [4].
Anyone would care to clarify ?
Hi Juliette,
Thank you for pointing out the discrepancy. You are correct that `default` is
just a special
case statement, and the intention in the RFC was to output the deprecation
message for default cases
as well (the example in the RFC included a default case followed by a semicolon
to highlight this).
The fact that a deprecation message isn't shown for default cases is an
oversight on my part
when I implemented the RFC. The merged implementation correctly updated the AST
for default
case statements followed by a semicolon to support the deprecation message, but
I failed to
notice that when the compiler code loops over switch cases, there is a
`continue` statement
when handling the default case which prevents reaching the code for the
deprecation.
I opened a follow-up pull request to fix this, which can hopefully be merged
before
PHP 8.5 is released: https://github.com/php/php-src/pull/20172
Hi Theodore,
Ah! That explains it. Bugs happen to the best of us. Glad to hear I
didn't misunderstand the intention of the RFC.
Thanks for clarifying and for the new PR to update the deprecation
implementation. Here's me hoping it will be merged soon.
Smile,
Juliette
