registrar: add templatefilter to mark a function as template filter (API) This patch also adds loadfilter() to templatefilters, because this combination helps to figure out how they cooperate with each other. Listing up loadfilter() in dispatch.extraloaders causes implicit loading template filter functions at loading (3rd party) extension. This change requires that "templatefilter" attribute of (3rd party) extension is registrar.templatefilter or so.

revset: inline _getaliasarg() function This function is now much simpler than before. Inlining small functions helps to extract a reusable alias processor.

revset: drop redundant check for unknown alias arguments Since _parsealiasdefn() rejects unknown alias arguments, _checkaliasarg() is unnecessary. New test is added to make sure unknown '$n' symbols are rejected.

revset: move tagging of alias arguments from tokenization to parsing phase In short, this patch moves the hack from tokenizedefn() to _relabelaliasargs(), which is called after parsing. This change aims to eliminate tight dependency on the revset tokenizer. Before this patch, we had to rewrite an alias argument to a pseudo function: "$1" -> "_aliasarg('$1')" ('symbol', '$1') -> ('function', ('symbol', '_aliasarg'), ('string', '$1')) This was because the tokenizer must generate tokens that are syntactically valid. By moving the process to the parsing phase, we can assign a unique tag to an alias argument. ('symbol', '$1') -> ('_aliasarg', '$1') Since new _aliasarg node never be generated from a user input, we no longer have to verify a user input at findaliases(). The test for _aliasarg("$1") is removed as it is syntactically valid and should pass the parsing phase.

revset: add test that should fail if '_aliasarg' tag is removed I'm going to refactor the alias processing functions. We need '_aliasarg' tag to limit the scope of the alias expansion, but it wasn't covered by the test. This patch adds the test that should fail if '_aliasarg' were 'symbol'. This is the first half of the second part of the "template alias" series. The whole series will consist of the following parts: 1. make parsed template tree to be compatible with parser functions (1d461ee26e1b and 73d01cba5810) 2. refactor alias processing to be less dependent on revset module (1/2 in this series) 3. extract reusable component to parser module 4. clean up it 5. extend it to support template syntax 6. add debugging/testing functions of template aliases 7. add alias expansion routine to templater

templater: do not strip non-quote characters from template config Before this patch, the first and last characters were stripped from ui.logtemplate and template.* if they were the same. It could lead to a strange result as quotes are optional. See the test for example.

rebase: fix crash when rebase aborts while rebasing obsolete revisions Before this patch, rebase --continue would crash when trying to resume a rebase of obsolete revisions whose successors were in the destination. This patch adds logic to recompute the mapping when rebase is resumed. This patch also adds a test that showcased the crash before the code change.

rebase: refactor of error handling code path for rebaseskipobsolete This patch extracts the error handling code path to go in a separate function. In the next patch we will able to reuse this logic and avoid duplicated code.

destutil: show message and hint at updating to the closed head as warning

destutil: make messages at updating to the closed head usual form This patch makes messages at updating to the closed head usual form for Mercurial as below: one line description of the problem with no period (a suggestion about how to move forward or get more info)