difference between onBufferOpen and onBufPaneOpen?

[matthias314]

I initially thought that the onBufferOpen callback would be only called once if a file is opened in several panes while onBufPaneOpen would be called once for each pane. However, this is not the case. As far as I can tell, every call to onBufPaneOpen is preceded by a call to onBufferOpen. (As an exception, the log buffers only triggers onBufferOpen.) What is the rationale behind this duplication? It seems to be that anything one does inside onBufferOpen could be done inside onBufPaneOpen.

[Andriamanitra]

It's not really duplication, Buffer and BufPane are different. Every BufPane has a Buffer inside it, but you may:

• open a new Buffer in a BufPane that is already open (for example by running open asd.txt), or
• open a BufPane with a Buffer that is already open (for example by running log because the log buffer is already opened at startup – not sure if there are other cases when this happens).

To demonstrate this I added the following event handlers to my ~/.config/micro/init.lua:

local micro = import("micro")

function onBufferOpen(buf)
    micro.Log(string.format("opened Buffer (name='%s')", buf:GetName()))
end

function onBufPaneOpen(bp)
    micro.Log(string.format("opened BufPane (id=%d) with Buffer (name='%s')", bp:ID(), bp.Buf:GetName()))
end

and ran micro -debug to produce the following log.txt (I've added annotations for the commands I ran):

2024/12/14 04:54:12 Micro started
2024/12/14 04:54:12 opened Buffer (name='No name')
2024/12/14 04:54:12 opened BufPane (id=0) with Buffer (name='No name')
2024/12/14 04:54:12 opened Buffer (name='Log')
2024/12/14 04:54:12 opened Buffer (name='No name')
2024/12/14 04:54:12 opened BufPane (id=1) with Buffer (name='No name')

# open asd.txt
2024/12/14 04:54:18 opened Buffer (name='asd.txt')

# open asdf.txt
2024/12/14 04:54:24 opened Buffer (name='asdf.txt')

# tab asdfsd.txt
2024/12/14 04:54:30 opened Buffer (name='asdfsd.txt')
2024/12/14 04:54:30 opened BufPane (id=2) with Buffer (name='asdfsd.txt')

# help
2024/12/14 04:54:34 opened Buffer (name='help.md')
2024/12/14 04:54:34 opened BufPane (id=3) with Buffer (name='Help help')

# log
2024/12/14 04:54:37 opened BufPane (id=4) with Buffer (name='Log')

# raw
2024/12/14 04:54:41 opened Buffer (name='No name')
2024/12/14 04:54:41 opened BufPane (id=0) with Buffer (name='No name')