fix: keep stepped range progress totals aligned

marimo/_plugins/stateless/status/_progress.py

@@ -392,6 +392,7 @@ def __init__(
         self.step: int = 1
         self.collection = collection
         self._is_async = isinstance(collection, AsyncIterable)
+        total_was_provided = total is not None
 
         if collection is not None:
             if total is None:
@@ -404,7 +405,7 @@ def __init__(
                         "A `total` must be provided."
                     )
 
-            if isinstance(collection, range):
+            elif total_was_provided and isinstance(collection, range):
                 self.step = cast(range, collection).step
 
         elif total is None:

tests/_plugins/stateless/status/test_progress.py

@@ -167,6 +167,22 @@ def test_progress_without_context():
             pass
 
 
+def test_progress_with_stepped_range_without_total() -> None:
+    assert runtime_context_installed() is False
+
+    progress = progress_bar(range(0, 10, 2))
+    assert list(progress) == [0, 2, 4, 6, 8]
+    assert (progress.progress.current, progress.progress.total) == (5, 5)
+
+
+def test_progress_with_stepped_range_and_total() -> None:
+    assert runtime_context_installed() is False
+
+    progress = progress_bar(range(0, 10, 2), total=10)
+    assert list(progress) == [0, 2, 4, 6, 8]
+    assert (progress.progress.current, progress.progress.total) == (10, 10)
+
+
 async def sleep(seconds):
     import asyncio