Show the user any errors that the graphviz programs may produce.

[kilian]

I began to think about this, and naturally came to use the new subprocess module (to easily get stdout/stderr/returncode), but it only exists for python 2.4. What's the policy about python version requirements? May we use subprocess, or a more compatible os.system() function?

[Peter Kropf]

I don't have a problem with using 2.4+ specific modules.

[kilian]

Well, I asked because of Trac requirements:

To install Trac, the following software packages must be installed: 
Python, version >= 2.3. 
Python 2.4 is not supported on Windows since there are no Subversion bindings available for it.

So, if we introduce 2.4-isms in the plugin code, it won't work on Windows and 2.3 installations. Perhaps it's worth to work on a 2.3 compatible version of the GraphViz plugin, what do you think?

[Peter Kropf]

I suppose that I spoke too soon. If we can avoid it, the Graphviz module shouldn't impose a newer version of Python than Trac.

It's been a while since I've done any cross platform process control. Any reason why we can't use one of the popen series?

[kilian]

I don't think so, I just have to familiarize with those. :) Feel free to go ahead on this if you want.

[Peter Kropf]

Release v0.4 now used popen2 to control and communicate with the graphviz program processes. As a result, the code checks the return code and any text that the graphviz program sends to stderr is displayed to the user.

[Jeff Hammel]

(In [6543]) display single region on /query page if selected; refs #85 ; 2.5 hours

[Jeff Hammel]

Replying to k0s:

(In [6543]) display single region on /query page if selected; refs #85 ; 2.5 hours

sorry, wrongtrac