Add documentation to auto_preview_timeout mentioning minus value for immediate update

[mark.m.mcmahon@…]

The TracIni section mentions to use 0 to disable the automatic preview.

I also thought that the following might be useful when setting this value:

• It cannot be a floating point number (has to be a whole number)
• Setting a minus value will update the preview immediately.

The attached patch will update the doc string for auto_preview_timeout.

[mark.m.mcmahon@…]

Patch to doc string for auto_preview_timeout

[Remy Blank]

Does it really update immediately for negative values? I couldn't remember :) So the improved documentation is certainly welcome.

[mark.m.mcmahon@…]

Yes - tested on Trac 0.12dev-r9359.

Are there any concerns that should be noted by setting it to a minus value? I love the fact it is updated immediately - but I have worries that it may cause problems with server load (though my servers are very lightly loaded)

[Remy Blank]

Replying to mark.m.mcmahon@…:

Are there any concerns that should be noted by setting it to a minus value? I love the fact it is updated immediately - but I have worries that it may cause problems with server load (though my servers are very lightly loaded)

Yes, we should probably warn about that. And also check that this effect is indeed desired, and not just an unwanted side-effect.

[Christian Boos]

Perhaps we should allow fractional delays (there was already a patch for FloatOption from eblot) if we want "real time" updates, but having an instantaneous update (is that one for every keypress?) is really too much I think. So better be able to specify e.g. 0.2 than -1 …

[Remy Blank]

Replying to cboos:

Perhaps we should allow fractional delays (there was already a patch for FloatOption from eblot) if we want "real time" updates,

Yes, I agree with that. I almost did that when I implemented the feature, but then didn't want to make the patch more complicated for review, and finally forgot about it.

but having an instantaneous update (is that one for every keypress?)

Every keypress would trigger an update, but they are serialized, so no new update request is sent until the reply to the previous one has been received.

Ok, let's do the FloatOption thing.

[Remy Blank]

That would be #7432.

[mark.m.mcmahon@…]

This sounds good to me too - in fact I tried a Float first.

New doc string would be ?

Inactivity timeout in seconds after which the automatic wiki preview 
triggers an update. Set this to 0 to disable automatic preview. This 
option can contain floating point values for example 0.2, 1.5. 
''The lower the setting the more requests will be made to the server.''
The default value is 2 seconds. (''since 0.12'')

[Remy Blank]

Changed [trac] auto_preview_timeout to a FloatOption, and fixed the docstring accordingly in [9364]. Negative values now also disable the automatic preview.