fs.writeFileSync options.mode not work when file already exists

[gemwuu]

echo 1 > a && ls -l a
# -rw-rw-r-- 1 admin admin 2 Aug 24 18:29 a

node -e "fs.writeFileSync('./a', 'echo world', {mode: 0o755})" && ls -l a
# -rw-rw-r-- 1 admin admin 10 Aug 24 18:29 a

./a
# bash: ./a: Permission denied

Even we specify the mode to be 0o755, fs.writeFileSync still doesn't change to file mode which is 0o644.

So the installer which uses fs.writeFileSync L63 won't make esbuild executable.

This is a default behavior on POSIX when trying to write Buffer to an existing file.

PR#1547 shall fix it.

[hyrious]

ref: nodejs/node#2249

[evanw]

This is true. However, how does this behavior manifest when you install esbuild? What are the steps to reproduce the problem you are experiencing, and on what system?

[gemwuu]

This is true. However, how does this behavior manifest when you install esbuild? What are the steps to reproduce the problem you are experiencing, and on what system?

I cusomized a npm installer, it would change the esbuild/bin/esbuild to default 0o644 when writing files into disk, and esbuild postinstall tries to overwrite bin/esbuild using a platform-specific npm package (e.g. esbuild-linux-arm64).

In this case, bin/esbuild won't have the 0o755 pemissions, so it's better to chmod than writeFile with mode 0o755.