help: merge section about uisetup() and extsetup() They are technically the same callback, called only once per process. The section name "ui setup" is confusing, so shouldn't be used.

help: add internals.extensions topic I think it's better to include the API overview in core as we now have the internals section in our help system. Retrieved from the wiki, and formatted as reST. Several wiki links are removed since they are invalid in the help. The sections about example extension are removed at all as they seemed too verbose. https://www.mercurial-scm.org/wiki/WritingExtensions

commandserver: send raw progress information to message channel This is pretty basic implementation to support GUI progress bar.

commandserver: make getpass() request distinct from normal prompt Otherwise, GUI clients would have to parse the prompt text.

commandserver: attach prompt default and choices to message These attributes are important to provide a GUI prompt to user.

test-commandserver: clean up quoting and location of dbgui extension This helps embedding '$' in the script.

ui: extract helpers to write message with type or label This provides a 'type' attribute to command-server clients, which seems more solid than relying on 'ui.<type>' labels. In future patches, type='progress' will be added to send raw progress information.

commandserver: add experimental option to use separate message channel This is loosely based on the idea of the TortoiseHg's pipeui extension, which attaches ui.label to message text so the command-server client can capture prompt text, for example. https://bitbucket.org/tortoisehg/thg/src/4.7.2/tortoisehg/util/pipeui.py I was thinking that this functionality could be generalized to templating, but changed mind as doing template stuff would be unnecessarily complex. It's merely a status message, a simple serialization option should suffice. Since this slightly changes the command-server protocol, it's gated by a config knob. If the config is enabled, and if it's supported by the server, "message-encoding: <name>" is advertised so the client can stop parsing 'o'/'e' channel data and read encoded messages from the 'm' channel. As we might add new message encodings in future releases, client can specify a list of encoding names in preferred order. This patch includes 'cbor' encoding as example. Perhaps, 'json' should be supported as well.

commandserver: fix reference before assignment error in pipeservice cleanup Spotted by the next patch.

dispatch: pass around ui.fmsg channel This will be set by the command server. See the next patch.

test-subrepo: document why share magically works even if subrepos are missing I was confused how it's working while reviewing fb490d798be0, "share: reload repo after adjusting it in postshare()."

packaging: add Fedora 29 target Differential Revision: https://phab.mercurial-scm.org/D5254

store: pass in decoded filename to narrow matcher

test-narrow-clone-stream: include no usefncache case which is broken Since 9aeb9e2d28a7, encoded filenames are filtered by the narrow matcher, which is clearly wrong.

test-narrow-clone-stream: include uppercase letter in filename This makes encoded filenames differ from the original names.