[TxMt] The file association war

[Allan Odgaard]

On 21/9/2006, at 16:54, Matthew Anderson wrote:

> This discussion made me curious about exactly how this works in OS  
> X.  If anyone is curious: [...]

Thanks -- I wanted to write up something on the blog, because I  
occasionally actually get what could be called hate mail regarding  
this plus I have a one-star rating on version tracker with this as  
the reason.

> [...] I think all of your customizations of preferred applications  
> are stored here:
>
>   ~/Library/Preferences/com.apple.LaunchServices.plist
>
> I haven't confirmed this for certain, but I imagine that the 'file  
> association war' mostly occurs in this plist

It does keep your customizations, yes. The problem however is, that  
generally users have no customizations, and that is when the problem  
arise.

If e.g. you install SubEthaEdit, and it says it can open cc files,  
the system will check if there is any hardwired binding for cc files,  
as there isn’t, it will see which apps can open cc files, if none are  
“apple default”, then it will randomly pick one.

Seeing how the user only has SEE to open cc files, that’s all fine,  
he gets SEE to open all his various text files.

Then one day he decides to try out TM, now there are suddenly two  
apps which can open cc files, and if both are in /Applications, the  
system appears to randomly pick one of them [1], so 50% of the time,  
the system will now open all the users files with TM instead of SEE,  
and the user will think that this is the doing of TM.





[1] It might actually be, that the system picks the newest one,  
logically that wouldn’t be a bad assumption, that the newest app  
which can handle a document type, is the one the user wants to use  
for that document type -- but for people trying out new software, it  
would almost always be a bad heuristic.