Possible breakage with ClojureScript 1.10.439

[arichiardi]

Hello!

I have noticed some possible breakage with the new ClojureScript 1.10.439. The way humane pretty prints the diff will likely break. I have not tried but I am copying that piece of code somewhere around here as well and it broke 😄

The repro looks like this:

[Rebel readline] Type :repl/help for online help info
cljs.user=> (require '[cljs.pprint :as pprint])
cljs.user=> (require '[goog.string :as gstring])
cljs.user=> (import '[goog.string StringBuffer])
nil
cljs.user=> (defn with-pretty-writer* [f]
       #_=>   (binding [*sb* (StringBuffer.)
       #_=>             *out* (pprint/get-pretty-writer (StringBufferWriter. *sb*))]
       #_=>     (f)))

#'cljs.user/write*
cljs.user=> (defn- write* [s]
       #_=>   (cljs.core/-write cljs.core/*out* s))

cljs.user=> (with-pretty-writer* #(write* "test"))
TypeError: Cannot read property "append" from undefined
	 cljs$core$IWriter$_write$arity$2 (.cljs_nashorn_repl/cljs/core.cljs:874:17)
	 cljs$core$_write (.cljs_nashorn_repl/cljs/core.cljs:750:1)
	 <anonymous> (.cljs_nashorn_repl/cljs/pprint.cljs:212:14)
	 cljs.core/-write (.cljs_nashorn_repl/cljs/core.cljs:750:1)
	 <anonymous> (.cljs_nashorn_repl/cljs/pprint.cljs:525:18)
	 cljs$core$_write (.cljs_nashorn_repl/cljs/core.cljs:750:1)
	 (<NO_SOURCE_FILE> <eval>:3:0)
	 (<NO_SOURCE_FILE> <eval>:2:0)
	 (<NO_SOURCE_FILE> <eval>:11:0)
	 (<NO_SOURCE_FILE> <eval>:1:0)
	 (<NO_SOURCE_FILE> <eval>:1:0)
	 (<NO_SOURCE_FILE> <eval>:1:0)

I will try to put together a fix but can't promise and of course we are on our own for using the binding that way 😄

[arichiardi]

Confirmed on Slack:

mfikes [< 1 minute ago]
Yes that binding of sb and its use in the same binding won’t work

[immoh]

Confirmed, seeing this when tests fail (PhantomJS):

actual: #object[TypeError TypeError: undefined is not an object (evaluating 'self__.sb.append')]