Potential for loss of history with svn2git

[Nicolás Alvarez]

2017-12-17 2:09 GMT-03:00 John Lawlor <jk.lawlor at gmail.com>:
> Hi,
>
> I have encountered this problem with svn2git. It may be more to do with poor
> repository structure in SVN, but it's worth highlighting all the same.
>
> Let's say we have the following in SVN:
>
> svn/projects/Modules/framework/file-appender/trunk
> svn/projects/Modules/framework/file-appender/branches
> svn/projects/Modules/framework/file-appender/tags
>
> svn/projects/Modules/framework/file-manager/trunk
> svn/projects/Modules/framework/file-manager/branches
> svn/projects/Modules/framework/file-manager/tags
>
> This is a pretty standard layout. However, for some reason the SVN
> administrator gave developers write access to Modules. Really, I think
> Modules should never have existed, it should probably be more like:
>
> svn/projects/file-appender
> svn/projects/file-manager
>
> This results in several places for history to be recorded in the SVN tree.
> If someone checks out 'Modules', they can make commits above 'trunk' into
> say file-appender:
>
> (from svn log)
>
> Changed paths:
> A Modules/framework/file-manager/trunk/pom.xml
>
> If you subsequently convert file-appender to git, using a rule like:
>
> match /projects/Modules/framework/file-appender/trunk
>
> the commit recorded at the Modules level will not appear in your converted
> repository. This makes sense as the commit wasn't made in 'trunk', it was
> made at 'Modules'.
>
> I am just wondering if this is really a problem or not. You might be missing
> the commit but I am thinking, should 'pom.xml' be modified later at 'trunk',
> the contents of the file will still be there from the commit made in the
> wrong place.
>
> What can and does happen though is if the file is never modified in 'trunk',
> after being created in 'Modules', it will be lost. It has no history in
> trunk, hence it doesn't exist.

I have no idea what you mean with "several places for history to be
recorded in the SVN tree" or "at the Modules level" etc...

If someone modifies
/projects/Modules/framework/file-appender/trunk/pom.xml, then "match
/projects/Modules/framework/file-appender/trunk/" will obviously match
it, since it's a prefix of the full path being modified. It doesn't
matter what you checked out when making the commit. Checking out /a/b
and making a change to c/d.txt and checking out /a and making a change
to b/c/d.txt gives exactly the same result: a commit that changes
/a/b/c/d.txt. The two cases aren't distinguishable in the resulting
SVN repository, and svn2git will work the same.

I see in your example you mention a change is done in file-manager,
and then you convert file-appender. I assume that's just a mistake in
your email? :)

-- 
Nicolás
Award-winning git repo surgeon