ENH: Allow passing read_only, data_only and keep_links arguments to openpyxl using engine_kwargs (#55807)

* ENH: Allow passing `read_only`, `data_only` and `keep_links` arguments to openpyxl using `engine_kwargs`

Previously it was not possible to override the default values for
`openpyxl.reader.excel.load_workbook`'s `read_only`, `data_only` and `keep_links`
arguments (see #55027).

Now these options can be changed via `engine_kwargs`.

Closes #55027

* test data_only roundtrip

* don't modify mutable parameter

Author: dweindl

doc/source/whatsnew/v2.2.0.rst

@@ -101,6 +101,7 @@ Other enhancements
 - :func:`tseries.api.guess_datetime_format` is now part of the public API (:issue:`54727`)
 - :meth:`ExtensionArray._explode` interface method added to allow extension type implementations of the ``explode`` method (:issue:`54833`)
 - :meth:`ExtensionArray.duplicated` added to allow extension type implementations of the ``duplicated`` method (:issue:`55255`)
+- Allow passing ``read_only``, ``data_only`` and ``keep_links`` arguments to openpyxl using ``engine_kwargs`` of :func:`read_excel` (:issue:`55027`)
 - DataFrame.apply now allows the usage of numba (via ``engine="numba"``) to JIT compile the passed function, allowing for potential speedups (:issue:`54666`)
 - Implement masked algorithms for :meth:`Series.value_counts` (:issue:`54984`)
 - Improved error message when constructing :class:`Period` with invalid offsets such as "QS" (:issue:`55785`)

pandas/io/excel/_openpyxl.py

@@ -567,12 +567,11 @@ def load_workbook(
     ) -> Workbook:
         from openpyxl import load_workbook
 
+        default_kwargs = {"read_only": True, "data_only": True, "keep_links": False}
+
         return load_workbook(
             filepath_or_buffer,
-            read_only=True,
-            data_only=True,
-            keep_links=False,
-            **engine_kwargs,
+            **(default_kwargs | engine_kwargs),
         )
 
     @property

pandas/tests/io/excel/test_openpyxl.py

@@ -13,6 +13,7 @@
     ExcelWriter,
     _OpenpyxlWriter,
 )
+from pandas.io.excel._openpyxl import OpenpyxlReader
 
 openpyxl = pytest.importorskip("openpyxl")
 
@@ -129,6 +130,31 @@ def test_engine_kwargs_append_data_only(ext, data_only, expected):
             # ExcelWriter needs us to writer something to close properly?
             DataFrame().to_excel(writer, sheet_name="Sheet2")
 
+        # ensure that data_only also works for reading
+        #  and that formulas/values roundtrip
+        assert (
+            pd.read_excel(
+                f,
+                sheet_name="Sheet1",
+                engine="openpyxl",
+                engine_kwargs={"data_only": data_only},
+            ).iloc[0, 1]
+            == expected
+        )
+
+
+@pytest.mark.parametrize("kwarg_name", ["read_only", "data_only"])
+@pytest.mark.parametrize("kwarg_value", [True, False])
+def test_engine_kwargs_append_reader(datapath, ext, kwarg_name, kwarg_value):
+    # GH 55027
+    # test that `read_only` and `data_only` can be passed to
+    #  `openpyxl.reader.excel.load_workbook` via `engine_kwargs`
+    filename = datapath("io", "data", "excel", "test1" + ext)
+    with contextlib.closing(
+        OpenpyxlReader(filename, engine_kwargs={kwarg_name: kwarg_value})
+    ) as reader:
+        assert getattr(reader.book, kwarg_name) == kwarg_value
+
 
 @pytest.mark.parametrize(
     "mode,expected", [("w", ["baz"]), ("a", ["foo", "bar", "baz"])]