Shebang parsing is slightly different when using the --check flag

[not-an-aardvark]

• Version: 7.8.0 (although this has existed since the --check flag was introduced in 5.0.0)
• Platform: macOS
• Subsystem: cli

When loading a module, Node finds the end of a shebang comment by searching for a \r or \n character.

When using the --check flag, Node finds the end of a shebang comment by searching for a character that is not matched by . in a regex.

The characters \u2028 and \u2029 are considered linebreaks in JS, so they aren't matched by . in a regex. As a result, a file with \u2028 or \u2029 in the shebang will load successfully as a module, but will cause an error when parsed with the --check flag.

Example file (contains \u2028 after bin):

#!/usr/bin
/env node
console.log("foo")

The same thing applies when piping code from stdin.

[TimothyGu]

We should probably have a require('internal/module').stripShebang to standardize the behavior.

[gibfahn]

Adding good first contribution, although it's more of a second or third contribution. The change landed in #12202, what's needed here is a test or tests for the behaviour.

[guylil]

Hi,

I am pretty new to contributing here,
Where should I put the test?
Thanks!
@gibfahn

[TimothyGu]

@guylil Actually sorry, this issue was already fixed in #12202 but we forgot to close it. Doing that now.

[not-an-aardvark]

We decided to leave it open because the fix didn't have any tests. #12202 (comment)

[TimothyGu]

@not-an-aardvark Ah oops.