fix: change stderr to stdout

[SocketSomeone]

No description provided.

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@swc/cli	Patch

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[kdy1]

Can you describe the reason?

[magic-akari]

The use of stderr for outputting information is intentional and by design.
Could you explain why you wish to switch to stdout?

[SocketSomeone]

Can you describe the reason?

The use of stderr for outputting information is intentional and by design. Could you explain why you wish to switch to stdout?

It seems that the current version of library is using the wrong stream for its messages. In our company, we rely on reading logs from stderr to detect issues and stop the build when something goes wrong. However, it feels odd to encounter "successful errors" in the error stream. shrug

[SocketSomeone]

• stdout (Standard Output): Used for regular program output, particularly results or information that is the intended product of the program's execution.

• stderr (Standard Error): Reserved for diagnostic messages, errors, warnings, or any information unrelated to the normal output.

Messages like "Successfully compiled ${filename} with swc" looks as information of program execution.

[magic-akari]

It seems that the current version of library is using the wrong stream for its messages. In our company, we rely on reading logs from stderr to detect issues and stop the build when something goes wrong. However, it feels odd to encounter "successful errors" in the error stream. shrug

I recommend using exit code detection instead of relying on stderr to determine errors. This is because stderr output could be tips, warnings, or any other information.

• stdout (Standard Output): Used for regular program output, particularly results or information that is the intended product of the program's execution.
• stderr (Standard Error): Reserved for diagnostic messages, errors, warnings, or any information unrelated to the normal output.

Messages like "Successfully compiled ${filename} with swc" looks as information of program execution.

What you cited is correct; for the SWC CLI, stdout should only be the compilation output.
If the output is a file, stdout should be empty.

The "Successfully compiled" message, however, is a notification unrelated to the normal output and is expected to be emitted to stderr.

[magic-akari]

Return zero exit code on success, non-zero on failure. Exit codes are how scripts determine whether a program succeeded or failed, so you should report this correctly. Map the non-zero exit codes to the most important failure modes.

Send output to stdout. The primary output for your command should go to stdout. Anything that is machine readable should also go to stdout—this is where piping sends things by default.

Send messaging to stderr. Log messages, errors, and so on should all be sent to stderr. This means that when commands are piped together, these messages are displayed to the user and not fed into the next command.

"Successfully compiled" is displayed to the user and should not be piped to the next command, so it is reasonable to output it to stderr.

This is an excellent CLI design guide, which I believe is worth referring to: https://clig.dev/

[SocketSomeone]

@magic-akari Thank you for attention and advice! We will try to use exit code! I think it can be closed.