[llvm-dev] [monorepo] Exception in migrate-downstream-fork during monorepo transition

[David Greene via llvm-dev]

It's probably worth filing a GitHub issue here:

https://github.com/jyknight/llvm-git-migration/issues

                        -David

"Nagurne, James via llvm-dev" <llvm-dev at lists.llvm.org> writes:

> Our team decided to try out the conversion process utilizing the tool
> from https://llvm.org/docs/Proposals/GitHubMove.html#basic-migration
>
> However, we’re currently blocked by an issue that I’d hope at least
> one other group who had used this script would have run into. I’m
> wondering if we’ve missed something fundamental, or if there’s a new,
> more robust process in place and the documentation is out of date.
>
> When running the script, I get the exception:
>
> …
>
> File "../llvm-git-migration/migrate-downstream-fork.py", line 151, in
> commit_filter
>
> candidate_upstreams = [self.svn_to_newrev[p[0]] for p in
> parent_svn_info]
>
> KeyError: 181274
>
> svn_to_newrev is the mapping which help bridge the gap between old and
> new repos using the common svn revision.
>
> In the monorepo, there’s commit 2f2aeb9b. It seems to be an
> amalgamation of 3 svn revisions.
>
> The log for this commit contains:
>
> llvm-svn: 181277
>
> llvm-svn: 181274
>
> llvm-svn: 181273
>
> However, when dumping out the svn_to_newrev map, I only get one
> reference to this commit:
>
> 181273: '2f2aeb9b6912046e9ea21ae259932c103333c444',
>
> 181274 is not present at all. This is a problem for commits whose
> parents include clang mirror commit f9abf237
>
> https://github.com/llvm-mirror/clang/commit/f9abf23757fd6d417e20f1862dcf9a2794c76f16
>
> The apparent assumption is that 1 monorepo commit is 1 svn revision,
> but this commit seems to break that assumption.
>
> Any information or help is greatly appreciated! I loathe to attempt
> applying all of our changes manually, and would be happy to patch the
> script if there is in fact an error J
>
> I haven’t tested it, but I’d bet the way to reproduce this would be:
>
> 1) Checkout the llvm-mirror for clang
>
> 2) Make a branch off of f9abf2375 and make a commit or two
>
> 3) Attempt to use the migration script to move that branch onto the
> monorepo
>
> Because that seems to be precisely what we did to cause the error.
>
> Regards,
>
> J.B. Nagurne
>
> Code Generation
>
> Texas Instruments
>
>
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