hgweb: open mapfile using templater.open_template() This will help us read templates from resources in frozen binaries. Differential Revision: https://phab.mercurial-scm.org/D8899

hgweb: simplify a constant-length list by converting to literal tuple The call to `.append()` has been unnecessary since d3dbdca92458 (hgweb: don't choke when an inexistent style is requested (issue1901), 2009-11-12). Differential Revision: https://phab.mercurial-scm.org/D8898

hgweb: remove some accesses to private member uimod._unset Differential Revision: https://phab.mercurial-scm.org/D8897

templater: try to read %include in mapfiles from resources The "show" style is an example of a style that uses an "%include" statement in its definition. This patch makes `hg log --style show` work. This takes the number of failing tests with PyOxidizer from 72 to 62. Differential Revision: https://phab.mercurial-scm.org/D8896

templater: unroll loop over mapfile directories I'll rewrite the handling of the `templatedir()` case in the next patch, so the two cases will be more different and the loop won't make as much sense. Differential Revision: https://phab.mercurial-scm.org/D8895

templater: make open_template() read from resources if in frozen binary This takes the number of failing tests with PyOxidizer from 87 to 72. Differential Revision: https://phab.mercurial-scm.org/D8894

templater: pass opened file-like object to templatespec I think I said earlier that I planned to create a special templatespec variant for built-in templates. That was true (I planned that), but I ended up (in this patch) just adding a file-like object to the `mapfile_templatespec()` variant instead. Differential Revision: https://phab.mercurial-scm.org/D8893

templater: replace templatepath() with function that also opens the file For frozen binaries, such as those created by PyOxidizer, I plan to make it so the templatespec can keep an opened file/resource to read from instead of needing a file path. Having `templatepath()` return an opened file should help with that. At this point, it's just a wasteful extra opening of mapfiles that we'll open again later. I'll update the read-side next so it reads from the file-like object without opening the file again. Differential Revision: https://phab.mercurial-scm.org/D8892

templater: start passing resource to read from into _readmapfile() This patch makes it so we pass in a file-like resource to read from instead of having `_readmapfile()` open the file. This is one more step towards making `_readmapfile()` able to read resources opened by from `importlib.resources`. We still need to pass in the mapfile path because it's used for loading dependent mapfiles from `%include` and `__base__`, and it's also used for giving the user better error messages. Besides that, one can safely call `_readmapfile()` with any file-like resource after this patch. Differential Revision: https://phab.mercurial-scm.org/D8891

templater: move stylemap() to hgweb_mod, since that's its only user `stylemap()` even has an error message that mentions "hgweb templates", so it seems that it's meant specifically for hgweb. Differential Revision: https://phab.mercurial-scm.org/D8890