tour: Range and Close example code fails to run

[ollipa]

Context: https://tour.golang.org/concurrency/4

The example code fails to run in the section "Range and Close" with an error message:

/usr/local/go/src/sync/pool.go:9:2: read /usr/local/go/src/runtime/symtab_test.go: read /usr/local/go/src/runtime/symtab_test.go: cannot allocate memory

Program exited.

The code compiles and runs if I change any line in the example code (eg. adding a new empty line).

[bgadrian]

The problem doesn't reproduce 100% of the times, you need to open a new tab (after a few runs or when you modify the txt it works.
From what I could debug is a matter of encoding or missing characters from the initial HTML text value.

The first request does NOT work (returns error).
The 2nd is the correct one (it works).
The differences is at the last 3 lines, after Println(i)

curl 'https://tour.golang.org/compile' -H 'cookie: ' -H 'origin: https://tour.golang.org' -H 'accept-encoding: gzip, deflate, br' -H 'accept-language: en-GB,en;q=0.9,en-US;q=0.8,ro;q=0.7' -H 'x-requested-with: XMLHttpRequest' -H 'pragma: no-cache' -H 'user-agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36' -H 'content-type: application/x-www-form-urlencoded; charset=UTF-8' -H 'accept: application/json, text/javascript, */*; q=0.01' -H 'cache-control: no-cache' -H 'authority: tour.golang.org' -H 'referer: https://tour.golang.org/concurrency/4' -H 'dnt: 1' --data 'version=2&body=package+main%0A%0Aimport+(%0A%09%22fmt%22%0A)%0A%0Afunc+fibonacci(n+int%2C+c+chan+int)+%7B%0A%09x%2C+y+%3A%3D+0%2C+1%0A%09for+i+%3A%3D+0%3B+i+%3C+n%3B+i%2B%2B+%7B%0A%09%09c+%3C-+x%0A%09%09x%2C+y+%3D+y%2C+x%2By%0A%09%7D%0A%09close(c)%0A%7D%0A%0Afunc+main()+%7B%0A%09c+%3A%3D+make(chan+int%2C+10)%0A%09go+fibonacci(cap(c)%2C+c)%0A%09for+i+%3A%3D+range+c+%7B%0A%09%09fmt.Println(i)%0A%09%7D%0A%7D%0A' --compressed

curl 'https://tour.golang.org/compile' -H 'cookie: ' -H 'origin: https://tour.golang.org' -H 'accept-encoding: gzip, deflate, br' -H 'accept-language: en-GB,en;q=0.9,en-US;q=0.8,ro;q=0.7' -H 'x-requested-with: XMLHttpRequest' -H 'pragma: no-cache' -H 'user-agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36' -H 'content-type: application/x-www-form-urlencoded; charset=UTF-8' -H 'accept: application/json, text/javascript, */*; q=0.01' -H 'cache-control: no-cache' -H 'authority: tour.golang.org' -H 'referer: https://tour.golang.org/concurrency/4' -H 'dnt: 1' --data 'version=2&body=package+main%0A%0Aimport+(%0A%09%22fmt%22%0A)%0A%0Afunc+fibonacci(n+int%2C+c+chan+int)+%7B%0A%09x%2C+y+%3A%3D+0%2C+1%0A%09for+i+%3A%3D+0%3B+i+%3C+n%3B+i%2B%2B+%7B%0A%09%09c+%3C-+x%0A%09%09x%2C+y+%3D+y%2C+x%2By%0A%09%7D%0A%09close(c)%0A%7D%0A%0Afunc+main()+%7B%0A%09c+%3A%3D+make(chan+int%2C+10)%0A%09go+fibonacci(cap(c)%2C+c)%0A%09for+i+%3A%3D+range+c+%7B%0A%09%09fmt.Println(i)%0A%09%7D%0A%09%0A%7D%0A' --compressed