DM-23359: Add support for __file__ in config files

python/lsst/pex/config/config.py

@@ -981,7 +981,7 @@ def load(self, filename, root="config"):
         """
         with open(filename, "r") as f:
             code = compile(f.read(), filename=filename, mode="exec")
-            self.loadFromStream(stream=code, root=root)
+            self.loadFromStream(stream=code, root=root, filename=filename)
 
     def loadFromStream(self, stream, root="config", filename=None):
         """Modify this Config in place by executing the Python code in the
@@ -1017,9 +1017,10 @@ def loadFromStream(self, stream, root="config", filename=None):
         lsst.pex.config.Config.saveFromStream
         """
         with RecordingImporter() as importer:
+            globals = {"__file__": filename}
             try:
                 local = {root: self}
-                exec(stream, {}, local)
+                exec(stream, globals, local)
             except NameError as e:
                 if root == "config" and "root" in e.args[0]:
                     if filename is None:
@@ -1032,7 +1033,7 @@ def loadFromStream(self, stream, root="config", filename=None):
                     print(f"Config override file {filename!r}"
                           " appears to use 'root' instead of 'config'; trying with 'root'", file=sys.stderr)
                     local = {"root": self}
-                    exec(stream, {}, local)
+                    exec(stream, globals, local)
                 else:
                     raise
 

setup.cfg

@@ -14,6 +14,7 @@ exclude =
   tests/.tests,
   testLib.py,
   ticket1914.py
+  tests/config/filename.py
 
 [tool:pytest]
 addopts = --flake8

tests/config/filename.py

@@ -0,0 +1,3 @@
+
+config.filename = __file__
+config.number = 5

tests/test__file__.py

@@ -0,0 +1,52 @@
+# This file is part of pex_config.
+#
+# Developed for the LSST Data Management System.
+# This product includes software developed by the LSST Project
+# (http://www.lsst.org).
+# See the COPYRIGHT file at the top-level directory of this distribution
+# for details of code ownership.
+#
+# This software is dual licensed under the GNU General Public License and also
+# under a 3-clause BSD license. Recipients may choose which of these licenses
+# to use; please see the files gpl-3.0.txt and/or bsd_license.txt,
+# respectively.  If you choose the GPL option then the following text applies
+# (but note that there is still no warranty even if you opt for BSD instead):
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import unittest
+import lsst.pex.config as pexConf
+
+TESTDIR = os.path.dirname(os.path.abspath(__file__))
+
+
+class FileConfig(pexConf.Config):
+    number = pexConf.Field("FileConfig.number", int, default=0)
+    filename = pexConf.Field("FileConfig.filename", str, default=None)
+
+
+class FilenameTestCase(unittest.TestCase):
+    """Check that __file__ can be used in a config file."""
+
+    def test__file(self):
+        c = FileConfig()
+        confFile = os.path.join(TESTDIR, "config", "filename.py")
+        c.load(confFile)
+        self.assertEqual(c.filename, confFile)
+        self.assertEqual(c.number, 5)
+
+
+if __name__ == "__main__":
+    unittest.main()