output.file can create multiple files on reopen

[vitoyucepi]

Describe the bug
I've found out that sometimes output.file can create two different files if the file name has seconds in it. This happens because the file name function is called several times, and the current time is near the round second.

To Reproduce

def file_name()
    a = time.string('/tmp/%H_%M_%S.mp3')
    print('file name is #{a}')
    a
end

output.file(
    reopen_delay=1.0,
    reopen_when={true},
    %ffmpeg(format="mp3", %audio(codec="libmp3lame", samplerate=48000, b="320k")),
    file_name,
    sine(480.)
)

2023/01/10 19:53:22 [/tmp/19_53_18.mp3:3] Re-opening output pipe.
file name is /tmp/19_53_22.mp3
file name is /tmp/19_53_22.mp3
file name is /tmp/19_53_22.mp3
2023/01/10 19:53:23 [/tmp/19_53_18.mp3:3] Re-opening output pipe.
file name is /tmp/19_53_23.mp3
file name is /tmp/19_53_23.mp3
file name is /tmp/19_53_24.mp3
2023/01/10 19:53:25 [/tmp/19_53_18.mp3:3] Re-opening output pipe.
file name is /tmp/19_53_25.mp3
file name is /tmp/19_53_25.mp3
file name is /tmp/19_53_25.mp3

#stat 19_53_23.mp3 
  File: 19_53_23.mp3
  Size: 43245     	Blocks: 88         IO Block: 4096   regular file
Device: 0,30	Inode: 69095       Links: 1
Access: (0644/-rw-r--r--)  Uid: (10000/ UNKNOWN)   Gid: (10001/ UNKNOWN)
Access: 2023-01-10 19:53:23.976039781 +0000
Modify: 2023-01-10 19:53:25.016028702 +0000
Change: 2023-01-10 19:53:25.016028702 +0000
 Birth: 2023-01-10 19:53:23.976039781 +0000
#stat 19_53_24.mp3 
  File: 19_53_24.mp3
  Size: 0         	Blocks: 0          IO Block: 4096   regular empty file
Device: 0,30	Inode: 69096       Links: 1
Access: (0644/-rw-r--r--)  Uid: (10000/ UNKNOWN)   Gid: (10001/ UNKNOWN)
Access: 2023-01-10 19:53:24.012706057 +0000
Modify: 2023-01-10 19:53:24.012706057 +0000
Change: 2023-01-10 19:53:24.012706057 +0000
 Birth: 2023-01-10 19:53:24.012706057 +0000

Expected behavior
I think that between reopen tries should be exactly the reopen_delay time, but it drifts slightly forward.
The file name function should not be called several times.

Version details

• OS: ubuntu:22.04 in docker
• Version: 2.1.3

Install method
Deb package from liquidsoap releases at github

Common issues
N/A