Added encoding support

README.md

@@ -372,6 +372,14 @@ replace = MyProject=={new_version}
 
   Can be multiple lines, templated using [Python Format String Syntax](https://docs.python.org/3/library/string.html#format-string-syntax).
 
+#### `encoding =`
+  **default:** `UTF-8`
+
+  Encoding to be used with the file. Might need to be set for files that
+  contain special characters and use a different encoding than UTF-8.
+
+  You can consult [the Python Documentation](https://docs.python.org/3/library/codecs.html#standard-encodings) for a list of possible encodings.
+
 ## Command-line Options
 
 Most of the configuration values above can also be given as an option on the command-line.

bumpversion/utils.py

@@ -75,7 +75,7 @@ def contains(self, search):
         if not search:
             return False
 
-        with open(self.path, "rt", encoding="utf-8") as f:
+        with open(self.path, "rt", encoding=self._versionconfig.encoding) as f:
             search_lines = search.splitlines()
             lookbehind = []
 
@@ -102,7 +102,7 @@ def contains(self, search):
 
     def replace(self, current_version, new_version, context, dry_run):
 
-        with open(self.path, "rt", encoding="utf-8") as f:
+        with open(self.path, "rt", encoding=self._versionconfig.encoding) as f:
             file_content_before = f.read()
             file_new_lines = f.newlines
 
@@ -141,7 +141,7 @@ def replace(self, current_version, new_version, context, dry_run):
             logger.info("%s file %s", "Would not change" if dry_run else "Not changing", self.path)
 
         if not dry_run:
-            with open(self.path, "wt", encoding="utf-8", newline=file_new_lines) as f:
+            with open(self.path, "wt", encoding=self._versionconfig.encoding, newline=file_new_lines) as f:
                 f.write(file_content_after)
 
     def __str__(self):

bumpversion/version_part.py

@@ -137,7 +137,7 @@ class VersionConfig:
     Holds a complete representation of a version string
     """
 
-    def __init__(self, parse, serialize, search, replace, part_configs=None):
+    def __init__(self, parse, serialize, search, replace, part_configs=None, encoding="utf-8"):
 
         try:
             self.parse_regex = re.compile(parse, re.VERBOSE)
@@ -154,6 +154,7 @@ def __init__(self, parse, serialize, search, replace, part_configs=None):
         self.part_configs = part_configs
         self.search = search
         self.replace = replace
+        self.encoding = encoding
 
 
     def order(self):

tests/test_cli.py

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 import argparse
 import logging
 import os
@@ -2234,6 +2235,33 @@ def test_retain_newline(tmpdir, configfile, newline):
     # and that it is of the right type
     assert new_config.endswith(b"[bumpversion:file:file.py]" + newline)
 
+@pytest.mark.parametrize("encoding", [None, "utf-8", "latin1"])
+def test_file_encoding(tmpdir, configfile, encoding):
+    tmpdir.join("file.py").write_binary(dedent("""
+        0.7.2
+        Some encoded Content: äöüß
+        """).strip().encode(encoding=encoding or "utf-8"))
+    tmpdir.chdir()
+
+    if encoding is None:
+        configstring = ""
+    else:
+        configstring = "encoding = %s" % encoding
+
+    tmpdir.join(configfile).write_binary(dedent(("""
+        [bumpversion]
+        current_version = 0.7.2
+        search = {current_version}
+        replace = {new_version}
+        [bumpversion:file:file.py]
+	%s
+        """) % configstring).strip().encode(encoding='UTF-8'))
+
+    # Ensure the program works (without any exceptions or errors)
+    # regardless of encoding if the encoding is configured
+    # correctly
+    main(["major"])
+
 
 def test_no_configured_files(tmpdir, vcs):
     tmpdir.join("please_ignore_me.txt").write("0.5.5")
@@ -2260,7 +2288,6 @@ def test_no_configured_files_still_file_args_work(tmpdir, vcs):
     assert "0.5.5" == tmpdir.join("please_ignore_me.txt").read()
     assert "1.1.2" == tmpdir.join("please_update_me.txt").read()
 
-
 class TestSplitArgsInOptionalAndPositional:
 
     def test_all_optional(self):