REGR: close corrupt files in ExcelFile (pandas-dev#41806)

Author: twoertwein

doc/source/whatsnew/v1.2.5.rst

@@ -18,6 +18,7 @@ Fixed regressions
 - Fixed regression in :meth:`DataFrame.sum` and :meth:`DataFrame.prod` when ``min_count`` and ``numeric_only`` are both given (:issue:`41074`)
 - Regression in :func:`read_csv` when using ``memory_map=True`` with an non-UTF8 encoding (:issue:`40986`)
 - Regression in :meth:`DataFrame.replace` and :meth:`Series.replace` when the values to replace is a NumPy float array (:issue:`40371`)
+- Regression in :func:`ExcelFile` when a corrupt file is opened but not closed (:issue:`41778`)
 
 .. ---------------------------------------------------------------------------
 

pandas/io/excel/_base.py

@@ -422,7 +422,11 @@ def __init__(self, filepath_or_buffer, storage_options: StorageOptions = None):
         elif hasattr(self.handles.handle, "read"):
             # N.B. xlrd.Book has a read attribute too
             self.handles.handle.seek(0)
-            self.book = self.load_workbook(self.handles.handle)
+            try:
+                self.book = self.load_workbook(self.handles.handle)
+            except Exception:
+                self.close()
+                raise
         elif isinstance(self.handles.handle, bytes):
             self.book = self.load_workbook(BytesIO(self.handles.handle))
         else:
@@ -440,8 +444,10 @@ def load_workbook(self, filepath_or_buffer):
         pass
 
     def close(self):
-        if hasattr(self.book, "close"):
-            # pyxlsb opens a TemporaryFile
+        if hasattr(self, "book") and hasattr(self.book, "close"):
+            # pyxlsb: opens a TemporaryFile
+            # openpyxl: https://stackoverflow.com/questions/31416842/
+            #     openpyxl-does-not-close-excel-workbook-in-read-only-mode
             self.book.close()
         self.handles.close()
 

pandas/io/excel/_openpyxl.py

@@ -528,12 +528,6 @@ def load_workbook(self, filepath_or_buffer: FilePathOrBuffer):
             filepath_or_buffer, read_only=True, data_only=True, keep_links=False
         )
 
-    def close(self):
-        # https://stackoverflow.com/questions/31416842/
-        #  openpyxl-does-not-close-excel-workbook-in-read-only-mode
-        self.book.close()
-        super().close()
-
     @property
     def sheet_names(self) -> list[str]:
         return self.book.sheetnames

pandas/tests/io/excel/test_readers.py

@@ -4,6 +4,7 @@
 )
 from functools import partial
 import os
+from pathlib import Path
 from urllib.error import URLError
 from zipfile import BadZipFile
 
@@ -1499,3 +1500,21 @@ def test_engine_invalid_option(self, read_ext):
         with pytest.raises(ValueError, match="Value must be one of *"):
             with pd.option_context(f"io.excel{read_ext}.reader", "abc"):
                 pass
+
+    def test_corrupt_files_closed(self, request, engine, read_ext):
+        # GH41778
+        errors = (BadZipFile,)
+        if engine is None:
+            pytest.skip()
+        elif engine == "xlrd":
+            import xlrd
+
+            errors = (BadZipFile, xlrd.biffh.XLRDError)
+
+        with tm.ensure_clean(f"corrupt{read_ext}") as file:
+            Path(file).write_text("corrupt")
+            with tm.assert_produces_warning(False):
+                try:
+                    pd.ExcelFile(file, engine=engine)
+                except errors:
+                    pass