Margins quit being reserved at the edge of the screen after upgrading to 0.9.2

[cole-mk]

Problem description

In my rc.xml I have margins set
<margin top="6" bottom="3" left="3" right="3" output="" />

After upgrading to 0.9.2, my waybar instances are positioned all the way at the top and bottom of the screen, and maximized windows extend all the way to the left and right edges.

I have tried copying the latest rc.xml.all to my config directory and only setting margins. I have also tried installing the labwc-git package from the AUR, which I believe pulls the latest commit from this repo. Neither of those things helped. However, downgrading labwc to version 0.9.1 does restore the margins.

Thank you for taking the time to look at this!

Steps to reproduce

1. Set margins to some value in rc.xml.
2. reconfigure or restart labwc
3. Open a program and maximize its window.

labwc build source

Release

labwc version

0.9.2

labwc environment

From a TTY or some display manager like lightdm

Distribution

Arch linux

[tokyo4j]

Sorry, this is due to my PR #2667. As a quick fix, you can remove output="" to restore the old behavior.

Like #3006, the cause is that we no longer skip empty values in <margin />. I guess we have the same issue in <touch deviceName="" mapToOutput="" mouseEmulation="no"/> advertised in rc.xml.all.

Now I think we underestimated the number of users who use empty values in rc.xml as "ignore" and we should restore the old behavior. @johanmalm @Consolatis What do you think?

[cole-mk]

As a quick fix, you can remove output="" to restore the old behavior.

Thank you! Its working as expected now.

[johanmalm]

My intuitive feel is that we should leave it as it is. I'm not basing that sentiment on logical reasoning or analysis, but merely on the fact that we've not had much feedback regarding this, and by now other users might have started relying on it the way it is.

In the manual it says output is optional; if this attribute is not provided (rather than leaving it an empty string) the margin will be applied to all outputs. which makes me think that the behavior described in this issue has always been like it.

Ref:

• https://labwc.github.io/labwc-config.5.html#margin

[johanmalm]

However, downgrading labwc to version 0.9.1 does restore the margins.

Sorry - just saw this. Right, so something has changed, but it's curious that the man page seems to describe the new behavior (unless I'm thinking about this the wrong way).

[tokyo4j]

Sorry - just saw this. Right, so something has changed, but it's curious that the man page seems to describe the new behavior (unless I'm thinking about this the wrong way).

Right, but rc.xml.all also says: If output is left empty, the margin will be applied to all outputs. So at least we should update either of those two documentations.

I have a mixed feeling about this. I'm regretting that I was too optimistic about empty value handling in my config parser refactor, but I also wonder it's worth restoring the old behavior (i.e. ignore empty values).

Pros for keeping the current behavior:

• Keeping an empty string just as empty string feels a bit more natural. I guess the reason we used to just ignore empty strings is that we used to handle every nodes in rcxml.c: entry() and it early-returned when the content was empty.
• Perhaps we can extend the use of empty strings in the future? (ref: rcxml: allow empty values in <libinput> #3011 (comment))

Pros for restoring the old behavior:

• More backward compatibility (though we already released 0.9.2 which broke this)