[Monotone-devel] Ancestry Graph

[Brian Campbell]

The information currently output by the agraph information is not as 
useful as it could be. I'm considering adding some more functionality, 
and wonder what people think of these ideas.

First of all, it outputs in VCG format, and I cannot find a working 
link to a copy of xvcg. It seems that xvcg stopped being updated in 
1995, so its viability in the future is questionable. GraphViz is much 
more widely used, actively maintained, and there are more tools which 
use its DOT file format, so it would probably be good to have monotone 
output dot format files, rather than xvcg format. What do people think 
of having me update it to output DOT format? Has someone already done 
this? I know I've found a perl script online which already converts the 
xvcg output of monotone into DOT format, but I don't know if anyone's 
integrated anything like that into monotone. Right now I'm using a 
hacked up version of that script to prototype my ideas, but I'd really 
like to integrate them into monotone, so they aren't dependent on the 
output format of the agraph and ls certs commands.

Also, I have found that it's very helpful to include in nodes 
information like the author, date, and first line of the changelog. I 
am not sure exactly how information like this should be handled. Not 
everyone wants the same set of information output. Also, it might be 
nice to be able to color nodes based on either author or branch, but 
again, that's something that people would want to do on an individual 
basis. I'm not sure exactly how I should handle this. One possibility 
is outputting a graph with all the possible information, and having a 
tool to munge it to the form that people want. If the format were 
originally DOT, it might be kind of annoying to format the text labels, 
because I would need to output key/value pairs for all of the various 
things people might like to see, and then manipulate those into a 
nicely readable version for the final output, and in dot, all you have 
is a string for a label, which isn't very convenient for selecting 
various different pieces of information. Another format, possibly an 
ad-hoc one, might work better. Another option is to pass some sort of 
format string specifying what information should be printed out to the 
agraph command, and having monotone generate the appropriate DOT file 
with the label already formatted. Any thoughts as to which I should do?

Finally, when I display the first line of the changelog, in a lot of 
cases, people put information that duplicates what's already available 
(like their name, email address, and the date). Do you think that maybe 
we should decide on a convention where the first line of the changelog 
is a summary of what changed, or allow people to prefix a line in the 
changelog with "summary:", or add an extra cert for a name for the 
change, like darcs does? This last one might also help if you could use 
the name as a selector. Although tags also sort of do this already, so 
it might be redundant. I just think it would be nice to have something 
descriptive attached to all or most manifests which could be displayed 
in the ancestry graph or in logs and could be used to select a 
particular manifest in a selector.

Anyhow, if anyone has any ideas about how this should be done, or has 
already done some of it, let me know.