Re: How to pre-empt git pull merge error?

Thomas Rast [off-list ref] writes:

Antoine Pelisse [off-list ref] writes:

quoted

quoted

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On Wed, 27 Nov 2013 15:17:27 +0000
Pete Forman [off-list ref] wrote:

quoted

I am looking for a way of detecting up front whether a git pull or
git merge would fail. The sort of script I want to perform is to
update a server.

    git fetch
    git okay
    stop server
    backup data
    git merge
    start server

I don't know a simple way to do the pre-merge check without actually
doing the merge (other than patching git merge to add a --dry-run
option)

Wouldn't that be a nice use-case for git-recursive-merge --index-only
($gmane/236753) ?

Possibly, but most of the use-cases for merge --dry-run are better
answered by the XY Problem question:

Can you step back and explain what the *underlying* goal is?

The above sounds a lot like a deployment script, and such scripts are
almost always better served by using an actual deployment tool, or
failing that, by using some form of checkout -f instead, to ensure
that they get whatever they are supposed to deploy.

(Using a merge to update is really terrible in the face of
non-fast-forward updates, especially when caused by rewriting history
to not include some commits.)

It is a deployment script and updates are fast-forward. There was a
problem on a test server where a file had been hacked to investigate an
issue. The next deploy failed with the merge error.

There are three approaches, which might all be done with git or an
actual deployment tool.

1. test early, bail out if deploy would fail
2. set target to good state before applying the merge
2a. discard changes
2b. stash changes

I intend to use (1). First I will need to clean up the stray files or add
more entries into .gitignore.

  test -z "$(git status --porcelain)"


-- 
Pete Forman
http://petef.22web.org/payg.html