project.ci: add --hint parameter

This is a stupid workaround for testing other CI systems on GitHub
Actions.

3 files changed, 36 insertions, 11 deletions

diff --git a/project/ci/boost.py b/project/ci/boost.py
index 1b47710..b1bf8de 100644
--- a/project/ci/boost.py
+++ b/project/ci/boost.py
@@ -29,6 +29,13 @@ def _parse_args(argv=None):
                         type=Linkage.parse,
                         help='how the libraries link to the runtime')
 
+    # The hint parameter is basically a workaround for when this is run on a
+    # CI, _but_ testing another CI is desired.  This shouldn't be used in a
+    # real CI workflow.
+    parser.add_argument('--hint', metavar='CI_NAME',
+                        choices=Dirs.all_ci_names(),
+                        help='CI system to use')
+
     parser.add_argument('b2_args', metavar='B2_ARG',
                         nargs='*', default=[],
                         help='additional b2 arguments, to be passed verbatim')
@@ -40,7 +47,7 @@ def build_ci(dirs, argv=None):
     args = _parse_args(argv)
     with setup_logging():
         if dirs is None:
-            dirs = Dirs.detect()
+            dirs = Dirs.detect(args.hint)
 
         version = dirs.get_boost_version()
         build_dir = dirs.get_build_dir()
diff --git a/project/ci/cmake.py b/project/ci/cmake.py
index 83a80e8..1694a5e 100644
--- a/project/ci/cmake.py
+++ b/project/ci/cmake.py
@@ -21,6 +21,12 @@ def _parse_args(argv=None):
         description=Dirs.get_cmake_help(),
         formatter_class=argparse.RawDescriptionHelpFormatter)
 
+    # The hint parameter is basically a workaround for when this is run on a
+    # CI, _but_ testing another CI is desired.  This shouldn't be used in a
+    # real CI workflow.
+    parser.add_argument('--hint', metavar='CI_NAME',
+                        choices=Dirs.all_ci_names(),
+                        help='CI system to use')
     parser.add_argument('--install', action='store_true',
                         help='install the project')
     parser.add_argument('--boost', metavar='DIR', dest='boost_dir',
@@ -36,7 +42,7 @@ def build_ci(dirs, argv=None):
     args = _parse_args(argv)
     with setup_logging():
         if dirs is None:
-            dirs = Dirs.detect()
+            dirs = Dirs.detect(args.hint)
 
         src_dir = dirs.get_src_dir()
         if args.subdir:
diff --git a/project/ci/dirs.py b/project/ci/dirs.py
index f1b1c57..60fbdf8 100644
--- a/project/ci/dirs.py
+++ b/project/ci/dirs.py
@@ -17,14 +17,20 @@ from project.utils import env
 
 class Dirs(abc.ABC):
     @staticmethod
-    def detect():
+    def detect(hint=None):
         matching = [ci for ci in _ALL_CI_LIST if ci.this_one()]
         if len(matching) == 0:
             raise RuntimeError('no CI system was detected')
-        if len(matching) > 1:
-            names = ', '.join(ci.get_name() for ci in matching)
-            raise RuntimeError(f"can't select a single CI system out of these: {names}")
-        return matching[0]
+        if len(matching) == 1:
+            return matching[0]
+        # The hint parameter is basically a workaround for when this is run
+        # on a CI, _but_ testing another CI is desired.
+        if hint is not None:
+            for ci in matching:
+                if ci.get_name() == hint:
+                    return ci
+        names = ', '.join(ci.get_name() for ci in matching)
+        raise RuntimeError(f"can't select a single CI system out of these: {names}")
 
     def __init__(self):
         pass
@@ -77,25 +83,31 @@ class Dirs(abc.ABC):
         pass
 
     @staticmethod
+    def all_ci_names():
+        return [ci.get_name() for ci in _ALL_CI_LIST]
+
+    @staticmethod
+    def join_ci_names():
+        return ', '.join(Dirs.all_ci_names())
+
+    @staticmethod
     def get_boost_help():
-        names = ', '.join(ci.get_name() for ci in _ALL_CI_LIST)
         return f'''Download & build Boost during a CI run.
 
 This is similar to running both project.boost.download & project.boost.build,
 but auto-fills some parameters from environment variables.
 
-The supported CI systems are: {names}.
+The supported CI systems are: {Dirs.join_ci_names()}.
 '''
 
     @staticmethod
     def get_cmake_help():
-        names = ', '.join(ci.get_name() for ci in _ALL_CI_LIST)
         return f'''Build a CMake project during a CI run.
 
 This is similar to running project.cmake.build, but auto-fills some parameters
 from environment variables.
 
-The supported CI systems are: {names}.
+The supported CI systems are: {Dirs.join_ci_names()}.
 '''