Fix missing f-strings, deprecated datetime, stale pylint directives

- Add f-prefix to three RuntimeError format strings in attributes.py
  that were printing literal {self.name} instead of the attribute name
- Replace deprecated datetime.utcnow() with datetime.now(timezone.utc)
  in all four export functions
- Update hardcoded version fallback from 1.1.0 to 2.0.0 and narrow
  bare except to except Exception in exporters.py
- Remove obsolete pylint no-self-use directives from reporting.py
  and iznn/__init__.py

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: CodeReclaimers

neat/attributes.py

@@ -86,7 +86,7 @@ def validate(self, config):
         min_value = getattr(config, self.min_value_name)
         max_value = getattr(config, self.max_value_name)
         if max_value < min_value:
-            raise RuntimeError("Invalid min/max configuration for {self.name}")
+            raise RuntimeError(f"Invalid min/max configuration for {self.name}")
 
 
 class IntegerAttribute(BaseAttribute):
@@ -130,7 +130,7 @@ def validate(self, config):
         min_value = getattr(config, self.min_value_name)
         max_value = getattr(config, self.max_value_name)
         if max_value < min_value:
-            raise RuntimeError("Invalid min/max configuration for {self.name}")
+            raise RuntimeError(f"Invalid min/max configuration for {self.name}")
 
 
 class BoolAttribute(BaseAttribute):
@@ -174,7 +174,7 @@ def mutate_value(self, value, config):
     def validate(self, config):
         default = str(getattr(config, self.default_name)).lower()
         if default not in ('1', 'on', 'yes', 'true', '0', 'off', 'no', 'false', 'random', 'none'):
-            raise RuntimeError("Invalid default value for {self.name}")
+            raise RuntimeError(f"Invalid default value for {self.name}")
 
 
 class StringAttribute(BaseAttribute):

neat/export/exporters.py

@@ -5,7 +5,7 @@
 NEAT network (FeedForward, Recurrent, CTRNN, IZNN) to the JSON format.
 """
 
-from datetime import datetime
+from datetime import datetime, timezone
 from .json_format import FORMAT_VERSION, get_function_info
 
 
@@ -15,9 +15,9 @@ def _get_neat_version():
         import neat
         if hasattr(neat, '__version__'):
             return neat.__version__
-        return "1.1.0"
-    except:
-        return "1.1.0"
+        return "2.0.0"
+    except Exception:
+        return "2.0.0"
 
 
 def export_feedforward(network, metadata=None):
@@ -72,7 +72,7 @@ def export_feedforward(network, metadata=None):
         "format_version": FORMAT_VERSION,
         "network_type": "feedforward",
         "metadata": {
-            "created_timestamp": datetime.utcnow().isoformat() + "Z",
+            "created_timestamp": datetime.now(timezone.utc).isoformat(),
             "neat_python_version": _get_neat_version(),
         },
         "topology": {
@@ -84,11 +84,11 @@ def export_feedforward(network, metadata=None):
         "nodes": nodes,
         "connections": connections
     }
-    
+
     # Add optional metadata if provided
     if metadata:
         data["metadata"].update(metadata)
-    
+
     return data
 
 
@@ -144,7 +144,7 @@ def export_recurrent(network, metadata=None):
         "format_version": FORMAT_VERSION,
         "network_type": "recurrent",
         "metadata": {
-            "created_timestamp": datetime.utcnow().isoformat() + "Z",
+            "created_timestamp": datetime.now(timezone.utc).isoformat(),
             "neat_python_version": _get_neat_version(),
         },
         "topology": {
@@ -156,11 +156,11 @@ def export_recurrent(network, metadata=None):
         "nodes": nodes,
         "connections": connections
     }
-    
+
     # Add optional metadata if provided
     if metadata:
         data["metadata"].update(metadata)
-    
+
     return data
 
 
@@ -218,7 +218,7 @@ def export_ctrnn(network, metadata=None):
         "format_version": FORMAT_VERSION,
         "network_type": "ctrnn",
         "metadata": {
-            "created_timestamp": datetime.utcnow().isoformat() + "Z",
+            "created_timestamp": datetime.now(timezone.utc).isoformat(),
             "neat_python_version": _get_neat_version(),
         },
         "topology": {
@@ -230,11 +230,11 @@ def export_ctrnn(network, metadata=None):
         "nodes": nodes,
         "connections": connections
     }
-    
+
     # Add optional metadata if provided
     if metadata:
         data["metadata"].update(metadata)
-    
+
     return data
 
 
@@ -298,7 +298,7 @@ def export_iznn(network, metadata=None):
         "format_version": FORMAT_VERSION,
         "network_type": "iznn",
         "metadata": {
-            "created_timestamp": datetime.utcnow().isoformat() + "Z",
+            "created_timestamp": datetime.now(timezone.utc).isoformat(),
             "neat_python_version": _get_neat_version(),
         },
         "topology": {

neat/iznn/__init__.py

@@ -147,7 +147,6 @@ def reset(self):
             n.reset()
 
     def get_time_step_msec(self):
-        # pylint: disable=no-self-use
         # TODO: Investigate performance or numerical stability issues that may
         # result from using this hard-coded time step.
         return 0.05

neat/reporting.py

@@ -128,7 +128,6 @@ def end_generation(self, config, population, species_set):
             print(f"Generation time: {elapsed:.3f} sec")
 
     def post_evaluate(self, config, population, species, best_genome):
-        # pylint: disable=no-self-use
         fitnesses = [c.fitness for c in population.values()]
         fit_mean = mean(fitnesses)
         fit_std = stdev(fitnesses)

progress-20260314.md

@@ -0,0 +1,43 @@
+# Progress Log — 2026-03-14
+
+## Code quality review and bug fixes
+
+Performed a full code review of the neat-python codebase, scanning all core modules for defects, typos, stale comments, and quality issues. Identified 11 issues total; fixed 5 in this session.
+
+### Fixed: Missing f-string prefixes in attribute validation (attributes.py)
+
+Three `raise RuntimeError(...)` calls in `FloatAttribute.validate`, `IntegerAttribute.validate`, and `BoolAttribute.validate` were plain strings instead of f-strings, so error messages would print the literal text `{self.name}` instead of the attribute name.
+
+- `neat/attributes.py:89` — FloatAttribute
+- `neat/attributes.py:133` — IntegerAttribute
+- `neat/attributes.py:177` — BoolAttribute
+
+### Fixed: Hardcoded fallback version and bare except in exporters (export/exporters.py)
+
+`_get_neat_version()` had a hardcoded fallback of `"1.1.0"` but the project version is `2.0.0`. Also used a bare `except:` clause which catches SystemExit, KeyboardInterrupt, etc. Changed fallback to `"2.0.0"` and narrowed to `except Exception:`.
+
+### Fixed: Deprecated datetime.utcnow() in exporters (export/exporters.py)
+
+All four exporter functions (`export_feedforward`, `export_recurrent`, `export_ctrnn`, `export_iznn`) used `datetime.utcnow().isoformat() + "Z"` which is deprecated since Python 3.12. Replaced with `datetime.now(timezone.utc).isoformat()` which produces a timezone-aware ISO 8601 string with `+00:00` suffix.
+
+### Fixed: Obsolete pylint directives (reporting.py, iznn/__init__.py)
+
+Removed `# pylint: disable=no-self-use` comments from two locations. The `no-self-use` check was removed from pylint in version 2.14.
+
+- `neat/reporting.py:131` — StdOutReporter.post_evaluate
+- `neat/iznn/__init__.py:150` — IZNN.get_time_step_msec
+
+### Other issues identified but not yet fixed
+
+1. **Destructive pickling side effects** — `DefaultGenomeConfig.__getstate__` and `DefaultSpeciesSet.__getstate__` call `next()` on `itertools.count` objects, advancing the counter on the original object.
+2. **FeedForwardNetwork.create mutates genome** — Writing to `cg.weight` when `random_values` or `unique_value` is set corrupts the genome. Also `if unique_value:` is falsy for 0.0.
+3. **best_genome tracking ignores fitness_criterion** — Always uses `>` even when `fitness_criterion = min`.
+4. **fitness_criterion attribute may not be set** — When `no_fitness_termination=True` and criterion is not max/min/mean.
+5. **Dead None check in stagnation.py:56** — `prev_fitness` can never be None.
+6. **Weaker connection filter in RecurrentNetwork/CTRNN** — Should match the stricter filter used by IZNN.
+
+### Files modified
+- `neat/attributes.py`
+- `neat/export/exporters.py`
+- `neat/reporting.py`
+- `neat/iznn/__init__.py`