templatekw: add {reporoot} keyword The "%b" in filename format string will be replaced with "{reporoot|basename}".

templatefilters: add dirname() filter This is different from stripdir() in that the last component is always removed.

templater: add function to help substituting patterns in template string This will be used to rewrite a filename pattern to a template string.

templater: extract function scanning template string This provides a tokenizer-level view of template fragments, and will be used to substitute patterns in outermost 'string' tokens.

tests: expand test coverage for updating phases Consolidating the tests demonstrated that there are behavior differences when pushing phases between bundle1 and bundle2. A reason for this is the behavior of legacy pushes where the client queries the state of phases and then conditionally updates phases after an "unbundle" is processed. This behavior is expected. The tests were incomplete because they only tested the case of a publishing repo. In this commit, we add a variant for a non-publishing repo. We still see some differences between the legacy and bundle2 exchanges. But they are less pronounced. The behavior of not firing a pushkey hook when phases are updated as part of changegroup application feels weird to me. I'm not sure if this is a feature or a bug. By the time the "pushkey" or "phases" bundle2 part is applied, the phases have already been moved on a publishing repository. We fire the "pushkey" hook regardless, even though it would be a no-op. This is the part that feels the most buggy.

tests: consolidate test-push-http.t and test-push-http-bundle1.t These tests were initially copies of each other. Now that we have #testcases support in .t tests, we can consolidate them. The changes to test-push-http.t reflect the differences between that file and test-push-http-bundle1.t. The variances in phases push behavior are the biggest differences. The test will be updated in a subsequent commit to make the differences more clear and to expand test coverage. For now, let's just port the differences verbatim to get the tests consolidated.

tests: port value-less unbundle capability test to test-push-http.t This test is present in test-push-http-bundle1.t. Let's add it to test-push-http.t to further unify the tests.

tests: add phase testing to test-push-http-bundle1.t test-push-http.t and test-push-http-bundle1.t were initially copies. Now that we have support for inline test variants, we can combine them. One of the variances between the tests is testing of phase moving. We add the missing code to test-push-http-bundle1.t.

cmdutil: narrow scope of KeyError in makefilename() It seemed too broad to catch a standard Python exception.

node: make bin() be a wrapper instead of just an alias This includes a full backout of 59affe7e and 30d0cb27. Per the review of the former, we'd rather adapt the API to behave like it used to (at least for now), and take a second run at it if it shows up in our performance numbers. I ran perfrevlogindex with and without this change and it didn't make a measurable difference, so maybe it's fine (despite my intuition to the contrary). Differential Revision: https://phab.mercurial-scm.org/D2279