updated in accordance with the new pyreq API

* Removed the decorator, because it's not applicable to new
  python_requires API.
* Similarly removed private _Meta class, which was hacky anyway.
* Removed automatic dependency on b2 package in development mode.
* Updated tests.

README.adoc

@@ -23,35 +23,34 @@ package:
 
 [source,python]
 ----
-from conans import python_requires
-b2 = python_requires("b2-helper/[>=0.7.1]@grisumbras/stable")
+class MyConan(ConanFile):
+    python_requires = "b2-helper/[>=0.7.1]@grisumbras/stable"
 ----
 
 == Usage
 
-=== Using decorator
+=== Using mixin
 
-The simplest way to use the package is via the class decorator
+The simplest way to use the package is via the mixin class:
 
 [source,python]
 ----
-@b2.build_with_b2
 class MyConan(ConanFile):
-    name = "..."
-    version = "..."
-    settings = "os", "arch", "compiler", "build_type"
+    python_requires = "b2-helper/[>=0.7.1]@grisumbras/stable"
+    python_requires_extend = "b2-helper.Mixin"
 ----
 
-The decorator provides default implementations for methods `build`, `package`
+The mixin provides default implementations for methods `build`, `package`
 and `test`. In order for it to work without any customization, project's
 jamroot file should be in `conanfile.source_folder` and the project should
 require no configuration beyond toolset initialization. If customization is
 required, the `ConanFile` subclass should override method `b2_setup_builder`:
 
 [source,python]
 ----
-@b2.build_with_b2
 class MyConan(ConanFile):
+    python_requires_extend = "b2-helper.Mixin"
+
     def b2_setup_builder(self, builder):
         builder.source_folder = "src"
         builder.build_folder = "build"
@@ -66,52 +65,15 @@ If you need to build specific targets, you can sepcify them via
 
 [source,python]
 ----
-@b2.build_with_b2
 class MyConan1(ConanFile):
-  b2_build_targets = "foo"
+    python_requires_extend = "b2-helper.Mixin"
+    b2_build_targets = "foo"
 
-@b2.build_with_b2
 class MyConan2(ConanFile):
-  b2_build_targets = "foo", "bar"
-----
-
-By default the decorator adds a build requirement on Boost.Build
-_in development mode_. If you wish to disable that set its keyword argument
-`build_require_b2` to `False`:
-
-[source,python]
-----
-@b2.build_with_b2(build_require_b2=False)
-class MyConan(ConanFile):
-    ...
+    python_requires_extend = "b2-helper.Mixin"
+    b2_build_targets = "foo", "bar"
 ----
 
-Alternatively, if you want to use a specific version of Boost.Build, set that
-keyword argument to a conan reference:
-
-[source,python]
-----
-@b2.build_with_b2(build_require_b2="boost_build/4.0.0@mycompany/stable)
-class MyConan(ConanFile):
-    ...
-----
-
-=== Using mixin
-
-Another convenient way to use the package is via a mixin class:
-
-[source,python]
-----
-class MyConan(b2.Mixin, ConanFile):
-    name = "..."
-    version = "..."
-    settings = "os", "arch", "compiler", "build_type"
-----
-
-Using mixin is equivalent to using the class decorator. Note, that since
-`ConanFile` class defines methods `build`, `package` and so on, it is important
-to put the mixin before it in the base class list.
-
 === Using helper
 
 The helper can be used by itself pretty much the same way as standard build

conanfile.py

@@ -31,13 +31,6 @@ def package_info(self):
         self.info.header_only()
 
 
-b2_reference = "b2/[>=4.0.0]"
-
-
-def join_arguments(args):
-    return " ".join(filter(None, args))
-
-
 def jamify(s):
     """
     Convert a valid Python identifier to a string that follows Boost.Build
@@ -640,12 +633,6 @@ def b2_setup_builder(self, builder):
 
         return builder
 
-    def build_requirements(self):
-        """Adds build requirement on b2 in development mode."""
-
-        if getattr(self, "_b2_reference", None) and self.develop:
-            self.build_requires(self._b2_reference)
-
     def build(self):
         """Configures and builds default targets."""
 
@@ -791,6 +778,7 @@ def configure(self):
                 file.write("  <%s>%s\n" % (k, path_escaped(v)))
             file.write("  ;\n")
 
+
     def build(self, *targets):
         """
         Run Boost.Build and build targets `targets` using the active options,
@@ -842,49 +830,8 @@ def _build(self, targets):
             self.conanfile.run(join_arguments(args))
 
 
-def build_with_b2(wrapped=None, build_require_b2=True):
-    def helper(wrapped):
-        meta = metaclass(build_require_b2)
-        return six.add_metaclass(meta)(wrapped)
-
-    if wrapped is None:
-        return helper
-    else:
-        return helper(wrapped)
-
-
-def metaclass(build_require_b2=True):
-    if build_require_b2 and not isinstance(build_require_b2, six.string_types):
-        return _Meta
-    else:
-        class _MetaWithCustomRef(_Meta):
-            reference = build_require_b2
-        return _MetaWithCustomRef
-
-
-def _subclass_index(lst, cls):
-    index = [i for (i, base) in enumerate(lst) if issubclass(base, cls)]
-    if index:
-        return index[0]
-    else:
-        return -1
-
-
-class _Meta(type):
-    reference = b2_reference
-
-    def __new__(cls, name, bases, namespace):
-        mixin_index = _subclass_index(bases, Mixin)
-        if mixin_index < 0:
-            cf_index = _subclass_index(bases, ConanFile)
-            if cf_index > -1:
-                bases = list(bases)
-                bases.insert(cf_index, Mixin)
-                bases = tuple(bases)
-
-        namespace["_b2_reference"] = cls.reference
-
-        return type.__new__(cls, name, bases, namespace)
+def join_arguments(args):
+    return " ".join(filter(None, args))
 
 
 def path_escaped(path):

test_package/build-targets/conanfile.py

@@ -9,11 +9,13 @@
     ConanFile,
     tools,
 )
-from get_helper_package import b2
+from get_helper_package import package_ref
 
 
-@b2.build_with_b2
 class MyConan(ConanFile):
+    build_requires = "b2/[*]"
+    python_requires = package_ref
+    python_requires_extend = "b2-helper.Mixin"
     exports_sources = "*.jam", "*.cpp"
 
     b2_build_targets = "install1", "install2"

test_package/build_folder/conanfile.py

@@ -5,12 +5,14 @@
 
 
 from conans import ConanFile
-from get_helper_package import b2
+from get_helper_package import package_ref
 import os
 
 
-@b2.build_with_b2
 class B2ToolTestConan(ConanFile):
+    build_requires = "b2/[*]"
+    python_requires = package_ref
+    python_requires_extend = "b2-helper.Mixin"
     exports_sources = "*.cpp", "*.jam"
 
     def b2_setup_builder(self, builder):

test_package/conanfile.py

@@ -1,3 +1,9 @@
+# Copyright (c) 2020 Dmitry Arkhipov <[email protected]>
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+
 from conans import (
     ConanFile,
     tools,
@@ -8,9 +14,6 @@
 class TestB2Helper(ConanFile):
     _tests = (
         "minimal",
-        "explicit_require_b2",
-        "custom_build_requires",
-        "custom_b2_reference",
         "source_folder",
         "build_folder",
         "options",

test_package/default-properties/conanfile.py

@@ -5,11 +5,14 @@
 
 
 from conans import ConanFile
-from get_helper_package import b2
+from get_helper_package import package_ref
 
 
-@b2.build_with_b2
 class B2ToolTestConan(ConanFile):
+    build_requires = "b2/[*]"
+    python_requires = package_ref
+    python_requires_extend = "b2-helper.Mixin"
+
     settings = "os", "compiler", "build_type", "arch",
     options = {"shared": [True, False]}
     default_options = {"shared": False}

test_package/free/conanfile.py

@@ -5,12 +5,14 @@
 
 
 from conans import ConanFile
-from get_helper_package import b2
+from get_helper_package import package_ref
 import os
 
 
-@b2.build_with_b2
 class B2ToolTestConan(ConanFile):
+    build_requires = "b2/[*]"
+    python_requires = package_ref
+    python_requires_extend = "b2-helper.Mixin"
     exports_sources = "*.cpp", "*.hpp", "*.jam"
 
     def b2_setup_builder(self, builder):

test_package/minimal/conanfile.py

@@ -5,11 +5,13 @@
 
 
 from conans import ConanFile
-from get_helper_package import b2
+from get_helper_package import package_ref
 
 
-b2.build_with_b2
 class MyConan(ConanFile):
     """This is pretty much the bare minimum package definition"""
 
+    build_requires = "b2/[*]"
+    python_requires = package_ref
+    python_requires_extend = "b2-helper.Mixin"
     exports_sources = "*.jam", "*.cpp"

test_package/modules/get_helper_package.py

@@ -9,4 +9,3 @@
 
 
 package_ref = os.environ.get("PACKAGE_REFERENCE")
-b2 = python_requires(package_ref)

test_package/options/conanfile.py

@@ -5,11 +5,13 @@
 
 
 from conans import ConanFile
-from get_helper_package import b2
+from get_helper_package import package_ref
 
 
-@b2.build_with_b2
 class B2ToolTestConan(ConanFile):
+    build_requires = "b2/[*]"
+    python_requires = package_ref
+    python_requires_extend = "b2-helper.Mixin"
     exports_sources = "*.cpp", "*.jam"
 
     def b2_setup_builder(self, builder):