BUG: read excel changes dtype param

Author: debnathshoham

pandas/io/excel/_base.py

@@ -358,6 +358,10 @@ def read_excel(
     mangle_dupe_cols=True,
     storage_options: StorageOptions = None,
 ):
+    kwargs = locals().copy()
+    for each in kwargs:
+        if isinstance(locals()[each], dict):
+            kwargs[each] = locals()[each].copy()
 
     should_close = False
     if not isinstance(io, ExcelFile):
@@ -369,32 +373,9 @@ def read_excel(
             "an ExcelFile - ExcelFile already has the engine set"
         )
 
+    del kwargs["io"], kwargs["engine"], kwargs["storage_options"]
     try:
-        data = io.parse(
-            sheet_name=sheet_name,
-            header=header,
-            names=names,
-            index_col=index_col,
-            usecols=usecols,
-            squeeze=squeeze,
-            dtype=dtype,
-            converters=converters,
-            true_values=true_values,
-            false_values=false_values,
-            skiprows=skiprows,
-            nrows=nrows,
-            na_values=na_values,
-            keep_default_na=keep_default_na,
-            na_filter=na_filter,
-            verbose=verbose,
-            parse_dates=parse_dates,
-            date_parser=date_parser,
-            thousands=thousands,
-            comment=comment,
-            skipfooter=skipfooter,
-            convert_float=convert_float,
-            mangle_dupe_cols=mangle_dupe_cols,
-        )
+        data = io.parse(**kwargs)
     finally:
         # make sure to close opened file handles
         if should_close:
@@ -498,7 +479,6 @@ def parse(
         mangle_dupe_cols=True,
         **kwds,
     ):
-
         if convert_float is None:
             convert_float = True
         else:

pandas/tests/io/data/excel/test_common_headers.ods

@@ -1278,6 +1278,13 @@ def test_ignore_chartsheets_by_int(self, request, read_ext):
         ):
             pd.read_excel("chartsheet" + read_ext, sheet_name=1)
 
+    def test_dtype_dict(self, read_ext):
+        filename = "test_common_headers" + read_ext
+        dtype_dict = {"a": str, "b": str, "c": str}
+        dtype_dict_copy = dtype_dict.copy()
+        pd.read_excel(filename, dtype=dtype_dict)
+        assert dtype_dict == dtype_dict_copy, "dtype dict changed"
+
 
 class TestExcelFileRead:
     @pytest.fixture(autouse=True)