[fpc-other] Git & SVN

[Mark Morgan Lloyd]

On 23/05/17 14:10, Mark Morgan Lloyd wrote:

> One question if I may. Subversion has revision numbers like 12345, and
> it's comparatively easy to query that and build it into a piece of
> software's version information. It's also trivial for a developer to
> look at the revision that he's currently working with, to say whether
> it's older or newer than revision 12345, and to get a log of what the
> relative changes were by /only/ knowing the revision number.
> Now I don't deny for a moment that Git has its advantages for
> distributed working. But am I correct in my understanding that it has
> nothing that maps directly onto the monotonic revision list of
> traditional VCSs including Subversion?

Apologies for the poor threading, but not all ML messages get through 
our gateway.

Thanks for the explanation Graeme, I hope that I'm not the only person 
here to find that instructive. So in the context of what I asked

 >   [reportdesigner (reportdesigner)]$ git describe
 >   v1.4.1-787-g45f932c1
 >
 > What does that output tell me:
 >   * Whatever code I'm working on is follow on from the "v1.4.1"
 >     release.
 >   * This line of [development] history has seen "787" commits
 >     since the v1.4.1 release.

says explicitly that the modification with the hash g45f932c1 takes the 
project on the Git repository under consideration to something that 
could usefully be described as v1.4.1-787, and you can use that in 
conversation without having to be online to a repository.

If multiple people were committing directly to the same repository (I 
presume Git supports that)  presumably they'd see a consistent sequence 
of version identifiers, i.e. very much like Subversion.

What happens in the case where there's multiple repositories? How 
brutally would each one have to be whacked before it was guaranteed that 
every one had the same correspondence of release-commit tuples and 
hashes? Could this be /forced/ at the project level and what 
implications would that have on the amount of data transferred to 
synchronise them?

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]