love.filesystem.lines is closing the file when it reaches the eof?

[hyreia]

I didn't see it in the documentation and I am wondering if this is expected behavior.

Code: Select all

function love.load()
  local file = love.filesystem.newFile("example")
  local ok, err = file:open("r")
  if not ok then assert(ok, err) end

  print("Is file open: "..tostring(file:isOpen()))
  for line in file:lines() do
    print(line)
    print("File is still open: "..tostring(file:isOpen()))
  end
  print("Is file open after reading in all the lines: "..tostring(file:isOpen()))
  
  print("When I try to close the file it returns: "..tostring(file:close()))
  
end

Returns this:

Is file open: true
First line.
File is still open: true
Second line.
File is still open: true
Third line.
File is still open: true
Here's a fourth.
File is still open: true
A fifth.
File is still open: true
A minor fall.
File is still open: true
A major lift.
File is still open: true
The broken code composing
File is still open: true
hallelujah
File is still open: true
Is file open after reading in all the lines: false
When I try to close the file it returns: false

I stumbled across this when trying to use this https://love2d.org/wiki/SICK and was wondering why I kept getting unexpected behavior.

So, I can work around this, but I'm wondering if there's any other gotchas like this. Like does read() work this way?
Also I noticed file:open() doesn't like full filepaths like using love.filesystem.getWorkingDirectory()...'/'..filename, it always says the file doesn't exist.

[kov_serg]

Do it by hand

Code: Select all

local function lines(f) return function() return f:read"l" end end

local f,err=io.open("dummy.lua","rb") if err then error(err) end
for line in lines(f) do print(line) end
f:close()

[hyreia]

Potentially related, I'm starting to wonder if this is a Windows 11 issuee. I recently had to upgrade and now it sometimes calls a resize event (love.resize) if I click out of the game window and click back in, yet it passes NO values into the resize event (w and h are nil). So it'll crash if I don't check them.

[RNavega]

I didn't see it in the documentation and I am wondering if this is expected behavior.

Checking the source, yes, the file is explicitly closed if :lines() reaches EOF:

• (11.x) https://github.com/love2d/love/blob/11. ... #L328-L333

• (12.x) https://github.com/love2d/love/blob/mai ... #L330-L335

Does sound like a useful thing to have in the wiki.
It turns out that forum users can edit the wiki, so I went and added a Note section to the File:lines() entry.

[dusoft]

I didn't see it in the documentation and I am wondering if this is expected behavior.

Checking the source, yes, the file is explicitly closed if :lines() reaches EOF:

• (11.x) https://github.com/love2d/love/blob/11. ... #L328-L333

• (12.x) https://github.com/love2d/love/blob/mai ... #L330-L335

Does sound like a useful thing to have in the wiki.
It turns out that forum users can edit the wiki, so I went and added a Note section to the File:lines() entry.

Thanks, RNavega. Users can edit wiki indeed and they also should, if they encounter strange behavior or broken code examples. This way they help others in the community.