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hyperfiddle 2026-01-19
Dustin Getz (Hyperfiddle) 2026-01-19T15:19:40.216919Z
This is a brutal enough Clojure footgun that I wanted to share: interaction between #_ and #?(:clj …) with no :cljs branch
(ns dustingetz.scratch)
#_#?(:clj 1)
(def foo 42) ; under cljs compilation, the #_ targets this def
(println foo) ; Use of undeclared Var dustingetz.scratch/foo🤯 8
😭 3
$ clj-kondo --lint test.cljc --lang cljs
test.cljc:4:10: error: Unresolved symbol: foo
linting took 14ms, errors: 1, warnings: 0I know Cursive has some clj-kondo integration, but it might only run with --lang clj
shaunlebron 2026-01-20T17:46:38.637639Z
Wow. Yeah I was reading earlier that reader conditionals are ignored instead of returning nil on unspecified platforms. And I've seen people use #_#_ to ignore the next two forms, so likewise "conditional ignores" and "explicit ignores" stack together I guess
Dustin Getz (Hyperfiddle) 2026-01-19T15:22:12.100299Z
this Clojure rough edge is the source of probably several spooky Electric compiler errors that I have personally experienced, it presents like a "clear shadow cache" kind of bug where there is no apparent link between the error and the program
😵💫 1
avocade 2026-01-21T16:48:22.456429Z
Yes, I have personally shot myself in the foot several times commenting out reader conditionals like this. Very painful and hair-tearing experiences, sometimes including a feeling of slowly going insane. Bad cocktail 🍸
No linter catches it?