Hello all,
A while back I reported an issue to the Windows Git project
<https://github.com/git-for-windows/git/issues/2218> that I observed in
Git for Windows 2.21.
The error message "Server does not allow request for unadvertised object"
is reported when a commit updating a submodule pointer points to a commit
that does not exist in the repository for that submodule, even if later
commits in the branch points to a commit that do exist in the submodule
repo.
This circumstance can easily occur if a developer (e.g)
* interactively rebases a branch "foo" in the submodule (e.g to integrate
commits from another branch before a larger rebase)
* commits the resulting submodule pointer "A" in the branch to the parent
repo
* then do further rebasing in the submodule, e.g to move up on top of the
"bar" branch
* commits that pointer "B" to the parent repo
* forgets to squash the history in the parent repo
* pushes the updated submodule "foo" branch to the online repo. (NOTE:
"B" is pushed, not "A")
* pushes the parent module branch to its online repo
When the parent repo is pulled by another developer, or an autobuild
system, the fetch operation fails with the message "Server does not allow
request for unadvertised object". A second fetch will complete
successfully.
IMO this kind of check should only happen if a commit with pointer to a
missing submodule is actively checked out. At most the above message
should be a warning, not a fatal error.
For manual fetch operations this is mostly a nuisance, but for
autobuilders this breaks the update operation, and the entire build
operation fails. That is unacceptable behavior in an automatic system
(errors if it breaks the checkout, yes; issues that are not relevant to
the actual checkout, no).
This issue prevents upgrading past 2.17 (since 2.18 and 2.19 had other
blocking issues, and 2.20 apparently introduced this issue). I have not
tested 2.22+ since I have not noticed any changelog messages that seem
related.
A test case can be found in issue 2218, linked above.
For reference, we do have a server-side git hook that verifies that
submodule pointers for the production branch is correct and exists in the
submodule's repo, and also is on branches that follows certain naming
conventions.
As an aside, I think this kind of error message would be have been better
suited as either a client-side push check, to prevent pushes of references
to such missing commits (Smartgit seems to have something like it, but I
think it only checks for the current branch in the submodule, not all
submodule reference commits). Alternatively, there could be a check of
this server-side.
Related to this, but not as problematic, just irritating, and also seen in
2.17, is a message "warning: Submodule in commit deadbee at path: '(NULL)'
collides with a submodule named the same. Skipping it." I think it is
related to recreating a git modules file on a different branch.
--
Sincerely,
Yngve N. Pettersen
Vivaldi Technologies AS
