Try to figure out if syntax makes a difference

Author: riedgar-ms

guidance/models/_model.py

@@ -546,7 +546,7 @@ def next(self, logits):
                             self._new_bytes_prob if self.compute_log_probs else 1.0,
                             self._captured_data,
                             self._captured_log_prob_data,
-                            self._token_count - self._last_token_count + 1,
+                            self._token_count - self._last_token_count,
                         )
 
                         self._last_token_count = self._token_count

tests/library/test_gen.py

@@ -74,7 +74,7 @@ def test_stop_quote(selected_model):
 
 
 def test_metrics_smoke(selected_model: models.Model):
-    lm = selected_model
+    lm = selected_model.copy()
     lm.reset_metrics()
 
     lm += "abcd"
@@ -99,7 +99,7 @@ def test_metrics_smoke(selected_model: models.Model):
 
 
 def test_metrics_select(selected_model: models.Model):
-    lm = selected_model
+    lm = selected_model.copy()
     lm.reset_metrics()
 
     lm += "This is a great day to "
@@ -118,6 +118,30 @@ def test_metrics_select(selected_model: models.Model):
     assert lm.engine_metrics.generated_tokens > prev_stats.generated_tokens
 
 
+def test_metrics_alt_expressions(selected_model: models.Model):
+    lm = selected_model.copy()
+    lm2 = selected_model.copy()
+    lm.reset_metrics()
+    lm2.reset_metrics()
+
+    prompt = "abcdefg"
+
+    lm += prompt + gen(max_tokens=10)
+    print(f"\nlm={str(lm)}")
+    print(f"{lm.engine_metrics=}\n")
+
+    lm2 += prompt
+    lm2 += gen(max_tokens=10)
+    print(f"\nlm2={str(lm2)}")
+    print(f"{lm2.engine_metrics=}\n")
+
+    assert str(lm) == str(lm2)
+    assert lm.engine_metrics.generated_tokens == 10
+    assert lm2.engine_metrics.generated_tokens == 10
+    assert lm.engine_metrics.forced_tokens == 0
+    assert lm2.engine_metrics.forced_tokens == 0
+
+
 def test_unicode(selected_model):
     # black makes this test ugly -- easier to read with fmt: off
     # fmt: off