Merge pull request SCons#4480 from Repiteo/non-serializable

Explicitly wrap non-serializable values in json dump

Author: bdbaddog

CHANGES.txt

@@ -44,6 +44,7 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
       prototype when including a header file.
 
   From Thaddeus Crews:
+    - Explicitly wrap non-serializable values in json dump
     - Implemented SCons.Util.sctyping as a safe means of hinting complex types. Currently
       only implemented for `Executor` as a proof-of-concept.
 

RELEASE.txt

@@ -80,6 +80,8 @@ IMPROVEMENTS
 - The NewParallel scheduler now only adds threads as new work requiring execution
   is discovered, up to the limit set by -j. This should reduce resource utilization
   when the achievable parallelism in the DAG is less than the -j limit.
+- Dumping an environment with `json` formatting will now explicitly specify if a given
+  value cannot be serialized.
 
 
 PACKAGING

SCons/Environment.py

@@ -1720,7 +1720,7 @@ def Dump(self, key=None, format: str='pretty'):
         elif fmt == 'json':
             import json
             def non_serializable(obj):
-                return str(type(obj).__qualname__)
+                return '<<non-serializable: %s>>' % type(obj).__qualname__
             return json.dumps(cvars, indent=4, default=non_serializable)
         else:
             raise ValueError("Unsupported serialization format: %s." % fmt)

SCons/EnvironmentTests.py

@@ -3177,11 +3177,12 @@ def test_NoClean(self) -> None:
     def test_Dump(self) -> None:
         """Test the Dump() method"""
 
-        env = self.TestEnvironment(FOO = 'foo')
+        env = self.TestEnvironment(FOO='foo', FOOFLAGS=CLVar('--bar --baz'))
         assert env.Dump('FOO') == "'foo'", env.Dump('FOO')
         assert len(env.Dump()) > 200, env.Dump()    # no args version
 
         assert env.Dump('FOO', 'json') == '"foo"'    # JSON key version
+        self.assertEqual(env.Dump('FOOFLAGS', 'json'), '"<<non-serializable: CLVar>>"')
         import json
         env_dict = json.loads(env.Dump(format = 'json'))
         assert env_dict['FOO'] == 'foo'    # full JSON version