tests: avoid implicit bytes -> unicode -> bytes roundtrip on Python 2 Before the change, there were two implicit conversions: * The format string was converted to unicode because the substituted values were unicode. * When printing the message in log(), the string was converted from unicode to str.

cext: make HgRevlogIndex_GetParents private again The rust's direct-ffi code need to access this function. Now that it `direct-ffi` is no more. We can make this function `static` again. This change was suggested by `Yuya Nishihara`.

setup-rust: remove the legacy 'direct-ffi' variant This variant have been abandoned for a while. Keeping it around just get people confused.

hghave: add a `rust` keyword to detect the use of compiled rust code The content of some on disk cache can varies when using rust (because it is faster to do so in the rust variant). So we need to be able to detect this case for some test. Differential Revision: https://phab.mercurial-scm.org/D8162

nodemap: check that a simple lookup works fine I realised the code was not exercised much. Differential Revision: https://phab.mercurial-scm.org/D8180

debuginstall: print if Rust extensions are installed This should make it easier to use the Rust extensions. Another patch on will be exposing a version and more useful information, but it can only be done on top of this very patch, since it is targeting the stable branch and the API has already changed on the default branch. Differential Revision: https://phab.mercurial-scm.org/D8248

nodemap: fix missing r-prefix on regular expression Looking at this regular expression, it's pretty obvious from reading it that it wanted to match literal ., but since the r was missing on the pattern it was matching any character. I guess we're just lucky nothing bad happened as a result. This was automatically fixed by pyupgrade, but I split it out into its own change because it seemed important. Differential Revision: https://phab.mercurial-scm.org/D8254