setup-rust: remove the legacy 'direct-ffi' variant

This variant have been abandoned for a while. Keeping it around just get people
confused.

rust/Cargo.lock

@@ -217,14 +217,6 b' dependencies = ['
 ]
 
 [[package]]
-name = "hgdirectffi"
-version = "0.1.0"
-dependencies = [
- "hg-core 0.1.0",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
 name = "lazy_static"
 version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"

rust/Cargo.toml

@@ -1,3 +1,3 b''
 [workspace]
-members = ["hg-core", "hg-direct-ffi", "hg-cpython"]
+members = ["hg-core", "hg-cpython"]
 exclude = ["chg", "hgcli"]

setup.py

@@ -3,6 +3,7 b''
 #
 # 'python setup.py install', or
 # 'python setup.py --help' for more options
+from __future__ import print_function
 
 import os
 
@@ -141,7 +142,9 b" hgrustext = os.environ.get('HGWITHRUSTEX"
 # TODO record it for proper rebuild upon changes
 # (see mercurial/__modulepolicy__.py)
 if hgrustext != 'cpython' and hgrustext is not None:
-    hgrustext = 'direct-ffi'
+    if hgrustext:
+        print('unkown HGWITHRUSTEXT value: %s' % hgrustext, file=sys.stderr)
+    hgrustext = None
 
 import ctypes
 import errno
@@ -543,7 +546,7 b' class hgbuildext(build_ext):'
         # Build Rust standalon extensions if it'll be used
         # and its build is not explictely disabled (for external build
         # as Linux distributions would do)
-        if self.distribution.rust and self.rust and hgrustext != 'direct-ffi':
+        if self.distribution.rust and self.rust:
             for rustext in ruststandalones:
                 rustext.build('' if self.inplace else self.build_lib)
 
@@ -1391,29 +1394,6 b' class RustExtension(Extension):'
             )
 
 
-class RustEnhancedExtension(RustExtension):
-    """A C Extension, conditionally enhanced with Rust code.
-
-    If the HGWITHRUSTEXT environment variable is set to something else
-    than 'cpython', the Rust sources get compiled and linked within
-    the C target shared library object.
-    """
-
-    def __init__(self, mpath, sources, rustlibname, subcrate, **kw):
-        RustExtension.__init__(
-            self, mpath, sources, rustlibname, subcrate, **kw
-        )
-        if hgrustext != 'direct-ffi':
-            return
-        self.extra_compile_args.append('-DWITH_RUST')
-        self.libraries.append(rustlibname)
-        self.library_dirs.append(self.rusttargetdir)
-
-    def rustbuild(self):
-        if hgrustext == 'direct-ffi':
-            RustExtension.rustbuild(self)
-
-
 class RustStandaloneExtension(RustExtension):
     def __init__(self, pydottedname, rustcrate, dylibname, **kw):
         RustExtension.__init__(
@@ -1453,7 +1433,7 b' extmodules = ['
         include_dirs=common_include_dirs,
         depends=common_depends,
     ),
-    RustEnhancedExtension(
+    Extension(
         'mercurial.cext.parsers',
         [
             'mercurial/cext/charencode.c',
@@ -1463,16 +1443,9 b' extmodules = ['
             'mercurial/cext/pathencode.c',
             'mercurial/cext/revlog.c',
         ],
-        'hgdirectffi',
-        'hg-direct-ffi',
         include_dirs=common_include_dirs,
         depends=common_depends
-        + [
-            'mercurial/cext/charencode.h',
-            'mercurial/cext/revlog.h',
-            'rust/hg-core/src/ancestors.rs',
-            'rust/hg-core/src/lib.rs',
-        ],
+        + ['mercurial/cext/charencode.h', 'mercurial/cext/revlog.h',],
     ),
     Extension(
         'mercurial.cext.osutil',