bundle2: fix raising errors during heads checking If the heads on the server differ from the ones reported seen by the client at bundle time, we raise a PushRaced exception. However, the part raising the exception was broken. To fix it, we move the PushRaced class in the error module so it can be accessible everywhere without an import cycle. A test is also added to prevent regression.

bundle2: gracefully handle UnknownPartError during unbundle Same as for Abort error, we catch the error, encode it into a bundle2 reply (expected by the client) and stream this reply. The client processing of the error will raise the exception again.

bundle2: catch UnknownPartError during local push When doing local push, UnknownPartError from the server will be raised directly to the client. We need to catch them too.

bundle2: catch UnknownPartError during pull We narrow the exception catching while pulling.

bundle2: catch UnknownPartError during push We narrow the exception catching while unbundling the push reply.

bundle2: use a more specific UnknownPartError when no handler is found KeyError is very generic, we need something more specific for proper error handling.

bundle2: make error testing more modular We have more than Abort to test.

bundle2: gracefully handle abort during unbundle Clients expect a bundle2 reply to their bundle2 submission. So we catch the Abort error and turn it into a bundle2 containing a part transporting the exception data. The unbundling of this reply will raise the error again.

bundle2: decorate exception raised during bundle processing This is a small hack to help us do some graceful error handling in bundle2 without major refactoring. See embedded comment for details.

histedit, i18n: replace '+' with concatenation to make hggettext happy