Use package name when Fire runs from __main__.py

When a package is executed via python -m, show the package name in help
output instead of __main__.py. Fixes #76.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: Hasan Özdemir

fire/core.py

@@ -103,7 +103,7 @@ def Fire(component=None, command=None, name=None, serialize=None):
         code 2. When used with the help or trace flags, Fire will raise a
         FireExit with code 0 if successful.
   """
-  name = name or os.path.basename(sys.argv[0])
+  name = name or _InferCommandName()
 
   # Get args as a list.
   if isinstance(command, str):
@@ -275,6 +275,18 @@ def _PrintResult(component_trace, verbose=False, serialize=None):
     Display(output, out=sys.stdout)
 
 
+def _InferCommandName():
+  """Return a sensible CLI name when Fire is invoked via python -m package."""
+  argv0 = sys.argv[0]
+  base = os.path.basename(argv0)
+  if base == '__main__.py':
+    package = sys.modules['__main__'].__package__  # pylint: disable=no-member
+    if package:
+      return package
+    return os.path.basename(os.path.dirname(os.path.abspath(argv0)))
+  return base
+
+
 def _DisplayError(component_trace):
   """Prints the Fire trace and the error to stdout."""
   result = component_trace.GetResult()

fire/fire_test.py

@@ -21,6 +21,7 @@
 import fire
 from fire import test_components as tc
 from fire import testutils
+from fire.core import _InferCommandName
 
 
 class FireTest(testutils.BaseTestCase):
@@ -57,6 +58,15 @@ def testFireDefaultName(self):
                                     stderr=None):
         fire.Fire(tc.Empty)
 
+  def testInferCommandNameForMainModule(self):
+    with mock.patch.object(sys, 'argv', ['sample/__main__.py']):
+      with mock.patch.object(sys.modules['__main__'], '__package__', 'sample'):
+        self.assertEqual(_InferCommandName(), 'sample')
+
+  def testInferCommandNameForScript(self):
+    with mock.patch.object(sys, 'argv', ['sample/cli.py']):
+      self.assertEqual(_InferCommandName(), 'cli.py')
+
   def testFireNoArgs(self):
     self.assertEqual(fire.Fire(tc.MixedDefaults, command=['ten']), 10)