Fix QRCode.clear() to properly reset the QRCode object.

qrcode/main.py

@@ -81,6 +81,7 @@ def __init__(
     ):
         _check_box_size(box_size)
         _check_border(border)
+        self.clear()
         self.version = version
         self.error_correction = int(error_correction)
         self.box_size = int(box_size)
@@ -91,7 +92,6 @@ def __init__(
         self.image_factory = image_factory
         if image_factory is not None:
             assert issubclass(image_factory, BaseImage)
-        self.clear()
 
     @property
     def version(self) -> int:
@@ -123,6 +123,7 @@ def clear(self):
         self.modules_count = 0
         self.data_cache = None
         self.data_list = []
+        self._version = None
 
     def add_data(self, data, optimize=20):
         """

qrcode/tests/regression/test_pil_clear.py

@@ -0,0 +1,55 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import pytest
+
+import qrcode
+from qrcode.constants import PIL_AVAILABLE
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+
+@pytest.mark.skipif(not PIL_AVAILABLE, reason="PIL is not installed")
+def test_qrcode_clear_resets_size(tmp_path: Path):
+    """
+    Test that QRCode.clear() properly resets the QRCode object.
+
+    Regression test for:
+
+        QRCode class not resizing down between runs
+        https://github.com/lincolnloop/python-qrcode/issues/392
+    """
+    test1_path = tmp_path / "test1.png"
+    test2_path = tmp_path / "test2.png"
+    test3_path = tmp_path / "test3.png"
+
+    # Create a QR code instance
+    qr = qrcode.QRCode(version=None)
+
+    # Generate first QR code
+    qr.add_data("https://example.com/")
+    qr.make(fit=True)
+    img1 = qr.make_image()
+    img1.save(test1_path)
+
+    # Clear and generate second QR code with different data
+    qr.clear()
+    qr.add_data("https://example.net/some/other/path")
+    qr.make(fit=True)
+    img2 = qr.make_image()
+    img2.save(test2_path)
+
+    # Clear and generate third QR code with same data as first
+    qr.clear()
+    qr.add_data("https://example.com/")
+    qr.make(fit=True)
+    img3 = qr.make_image()
+    img3.save(test3_path)
+
+    # Check that the first and third QR codes are identical.
+    with test1_path.open("rb") as file1, test3_path.open("rb") as file3:
+        assert file1.read() == file3.read(), (
+            "First and third QR codes should be identical after clearing"
+        )