base_url for many projects is painful

[doki_pen <doki_pen@…>]

Setting the base_url in hundreds of ini files, and changing them with a hostname change is painful. I've attached a patch for a parent_base_url trac.ini setting that can be used in a parent trac.ini.

[doki_pen <doki_pen@…>]

Add a parent_base_url setting.

[osimons]

It would be useful, and it was also briefly raised by me on #5064 a while back.

As I see it, there are two alternatives:

1. Like your patch introduce a new setting for 'parent'.
2. Or, introduce substitusion in the original base_url so that you can write base_url = http://myhost/trac/$folder for instance.

Regardless, many places in Trac and not least external plugins and scripts make reference to the base_url setting, so I expect a fair amount of breakage for any change in setting or calculation (like the story with #5064). I need other devs to chime in with their opinion before anything gets committed.

[doki_pen <doki_pen@…>]

I originally tried using the interpolation feature in ConfigParser? to do something like this

# parent.trac.ini
[trac]
parent_base_url = http://myhost/trac

# trac.ini
[inherit]
file = parent.trac.ini

[trac]
base_url = %(parent_base_url)/myproject

But discovered that it doesn't work. The inheritance feature is implemented at a higher level then the interpolation feature. Perhaps this should work and the is what should be changed, but it seemed more difficult.

[dave@…]

Mightn't it be easier as environ?