Changelist analogy confusing

C. Michael Pilato cmpilato at
Thu Aug 14 09:47:39 CDT 2008

James Kistruck wrote:
> Hi,
> Sorry, I don't have a patch for this - I'm just getting started with SVN.
> I find Gmail tags a confusing analogy for changelists (Ch.3).  The whole 
> point of tags (over folders) is that you can have a 1:M mapping between 
> content and groupings.  One piece of content can be a member of many 
> groups, through its set of tags.
> Changelists don't allow that.. They enforce a 1:1 mapping between 
> content and groupings, so that a given piece of content (file) exists in 
> at most one group (changelist).  This is exactly like a directory 
> hierarchy, or the "files and folders paradigm" that Ch.3 suggests has 
> been surpassed by changelists.
> A more helpful analogy might be that of separating music tracks into 
> genres.  Any given track can be a member of only one genre (in most 
> virtual jukeboxes, if not in real life!), but there is no implicit 
> ordering of genres.  You can view your tracks by genre, but that doesn't 
> prevent you viewing them in another way (say by artist).
> James.

James, thanks for the feedback.  Sorry the analogy doesn't work for you. 
Part of the reason I choose the tags/labels analogy was to be a little 
forward-looking.  Nobody believes that the limitation of a single changelist 
per file in Subversion is altogether ideal.  So by describing the state of 
the feature as most of the Subversion developers think of it, plus the 
current limitation it carries, the text more accurately describes the 
intended design of the feature.

The decision to use this analogy has also been affirmed by the various 
in-person encounters I've had with folks just hearing about the feature 
(I've given multiple public talks about Subversion 1.5's features).  They 
"get" the analogy, even with the current limitation.

That's not to say anything negative about you, of course -- most analogies 
are imperfect because the recipient has mental baggage around the analogous 
concept that the producer of the analogy didn't anticipate.  For example, 
your jukebox genre analogy doesn't hit me perfectly because the available 
genres are often pre-defined, not able to be arbitrarily named like 
changelists or labels or tags can.

C. Michael Pilato <cmpilato at> |

"The Christian ideal has not been tried and found wanting.  It has
  been found difficult; and left untried."  -- G. K. Chesterton

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