Give filename and context for UnicodeDecodeError

These errors are a pain to debug otherwise, and might look like
Kconfiglib brokenness.

Another option would be ignore decoding errors, or do the
'surrogateescape' thing on reading and writing, but keep it simple for
now. Pointing out the problem might be more helpful.

1 files changed, 26 insertions, 4 deletions

diff --git a/kconfiglib.py b/kconfiglib.py
index 8169c11..96c7d37 100644
--- a/kconfiglib.py
+++ b/kconfiglib.py
@@ -657,10 +657,14 @@ class Kconfig(object):
 
         self._file = self._open(filename)
 
-        self._parse_block(None,           # end_token
-                          self.top_node,  # parent
-                          self.top_node,  # prev
-                          self.y)         # visible_if_deps
+        try:
+            self._parse_block(None,           # end_token
+                              self.top_node,  # parent
+                              self.top_node,  # prev
+                              self.y)         # visible_if_deps
+        except UnicodeDecodeError as e:
+            _decoding_error(e, self._filename)
+
         self.top_node.list = self.top_node.next
         self.top_node.next = None
 
@@ -738,6 +742,8 @@ class Kconfig(object):
         # This stub only exists to make sure _warn_no_prompt gets reenabled
         try:
             self._load_config(filename, replace)
+        except UnicodeDecodeError as e:
+            _decoding_error(e, filename)
         finally:
             self._warn_no_prompt = True
 
@@ -4341,6 +4347,22 @@ def _internal_error(msg):
         "email service to tell me about this. Include the message above and "
         "the stack trace and describe what you were doing.")
 
+def _decoding_error(e, filename):
+    # Gives the filename and context for UnicodeDecodeError's, which are a pain
+    # to debug otherwise. 'e' is the UnicodeDecodeError object.
+
+    raise KconfigSyntaxError(
+        "\n"
+        "Malformed {} in {}\n"
+        "Context: {}\n"
+        "Problematic data: {}\n"
+        "Reason: {}".format(
+            e.encoding, filename,
+            e.object[max(e.start - 40, 0):e.end + 40],
+            e.object[e.start:e.end],
+            e.reason))
+
+
 # Printing functions
 
 def _sym_choice_str(sc):