Comment lines which are environment variable assignments in .env file are not ignored when using --env-file

[Simon-Prieul]

Version

v20.12.2

Platform

Linux arthur 6.8.0-76060800daily20240311-generic #202403110203171139393022.04~331756a SMP PREEMPT_DYNAMIC Mon M x86_64 x86_64 x86_64 GNU/Linux

Subsystem

No response

What steps will reproduce the bug?

I found a regression starting in Node v20.12.0 for the parsing of .env files with the CLI option --env-file
The comment lines (starting with #) should be ignored, which seem to no longer be the case

With the following index.js :

console.log(`Starting with node version ${process.version}`)
const vars = Object.entries(process.env).filter(([evName]) => {
  return evName.startsWith("FOO_")
})
console.log(vars)
console.log("count: " + vars.length)

and the following .env file :

# FOO_ONE=
FOO_TWO=fooTwoVal
FOO_AAA=

How often does it reproduce? Is there a required condition?

No response

What is the expected behavior? Why is that the expected behavior?

When running the command node --env-file .env index.js
The expected behavior is the output should be the same that when running with Node v20.11.1 :

[ [ 'FOO_AAA', '' ], [ 'FOO_TWO', 'fooTwoVal' ] ]
count: 2

Indeed, in the .env file, the FOO_ONE variable was commented, and should not be set

What do you see instead?

When running the command node --env-file .env index.js
The ouptut is :

[ [ 'FOO_AAA', '' ], [ 'FOO_ONE', '' ], [ 'FOO_TWO', 'fooTwoVal' ] ]
count: 3

You can see that FOO_ONE was set to an empty string whereas it was not set in the .env file (the line # FOO_ONE= is present but it should be ignored as it is a comment line)

Additional information

Note that the bug seems to be present in Node v21.7.3 too

[IlyasShabi]

Thanks for reporting this @Simon-Prieul
The issue has been addressed in this PR
I identified a minor bug that occurs when the env file ends with KEY= (without a value) and EOF is not a newline character. I'm adding a commit to resolve this in the same PR

[Simon-Prieul]

Thanks for reporting this @Simon-Prieul The issue has been addressed in this PR I identified a minor bug that occurs when the env file ends with KEY= (without a value) and EOF is not a newline character. I'm adding a commit to resolve this in the same PR

@IlyasShabi From what I have tested, the issue is not restricted to the .env ending with KEY= or EOF not being a newline character. Even if my test .env file does not fill those conditions, the bug still occurs.

For instance with the following (with a newline at the end) :

# FOO_ONE=fooOneVal
FOO_TWO=fooTwoVal

The output is still wrong: [ [ 'FOO_ONE', 'fooOneVal' ], [ 'FOO_TWO', 'fooTwoVal' ] ] instead of the expected [ [ 'FOO_TWO', 'fooTwoVal' ] ] Sadly the commented line is still parsed and the FOO_ONE var is assigned 😞

[IlyasShabi]

@Simon-Prieul what I meant is that the issue you mentioned has been fixed in this PR #52406.
Additionally, I found another minor bug and also fixed within the same pull request