ARROW-10214: [Python] Allow printing undecodable schema metadata

python/pyarrow/_flight.pyx

@@ -51,7 +51,7 @@ cdef int check_flight_status(const CStatus& status) nogil except -1:
     detail = FlightStatusDetail.UnwrapStatus(status)
     if detail:
         with gil:
-            message = frombytes(status.message())
+            message = frombytes(status.message(), safe=True)
             detail_msg = detail.get().extra_info()
             if detail.get().code() == CFlightStatusInternal:
                 raise FlightInternalError(message, detail_msg)
@@ -72,7 +72,7 @@ cdef int check_flight_status(const CStatus& status) nogil except -1:
     size_detail = FlightWriteSizeStatusDetail.UnwrapStatus(status)
     if size_detail:
         with gil:
-            message = frombytes(status.message())
+            message = frombytes(status.message(), safe=True)
             raise FlightWriteSizeExceededError(
                 message,
                 size_detail.get().limit(), size_detail.get().actual())

python/pyarrow/_parquet.pyx

@@ -177,7 +177,7 @@ cdef class ParquetLogicalType(_Weakrefable):
         self.type = type
 
     def __str__(self):
-        return frombytes(self.type.get().ToString())
+        return frombytes(self.type.get().ToString(), safe=True)
 
     def to_json(self):
         return frombytes(self.type.get().ToJSON())
@@ -715,8 +715,9 @@ cdef class ParquetSchema(_Weakrefable):
         self.schema = container._metadata.schema()
 
     def __repr__(self):
-        return """{0}
-{1}""".format(object.__repr__(self), frombytes(self.schema.ToString()))
+        return "{0}\n{1}".format(
+            object.__repr__(self),
+            frombytes(self.schema.ToString(), safe=True))
 
     def __reduce__(self):
         return ParquetSchema, (self.parent,)

python/pyarrow/array.pxi

@@ -790,7 +790,7 @@ cdef class Array(_PandasConvertible):
         cdef c_string result
         with nogil:
             result = self.ap.Diff(deref(other.ap))
-        return frombytes(result)
+        return frombytes(result, safe=True)
 
     def cast(self, object target_type, safe=True):
         """
@@ -992,7 +992,7 @@ cdef class Array(_PandasConvertible):
                 )
             )
 
-        return frombytes(result)
+        return frombytes(result, safe=True)
 
     def format(self, **kwargs):
         import warnings

python/pyarrow/table.pxi

@@ -79,7 +79,7 @@ cdef class ChunkedArray(_PandasConvertible):
                 )
             )
 
-        return frombytes(result)
+        return frombytes(result, safe=True)
 
     def format(self, **kwargs):
         import warnings

python/pyarrow/tests/test_schema.py

@@ -707,3 +707,14 @@ def test_schema_merge():
 
     with pytest.raises(pa.ArrowInvalid):
         pa.unify_schemas([b, d])
+
+
+def test_undecodable_metadata():
+    # ARROW-10214: undecodable metadata shouldn't fail repr()
+    data1 = b'abcdef\xff\x00'
+    data2 = b'ghijkl\xff\x00'
+    schema = pa.schema(
+        [pa.field('ints', pa.int16(), metadata={'key': data1})],
+        metadata={'key': data2})
+    assert 'abcdef' in str(schema)
+    assert 'ghijkl' in str(schema)

python/pyarrow/types.pxi

@@ -154,7 +154,7 @@ cdef class DataType(_Weakrefable):
         return self.type.layout().buffers.size()
 
     def __str__(self):
-        return frombytes(self.type.ToString())
+        return frombytes(self.type.ToString(), safe=True)
 
     def __hash__(self):
         return hash(str(self))
@@ -888,7 +888,7 @@ cdef class KeyValueMetadata(_Metadata, Mapping):
         return str(self)
 
     def __str__(self):
-        return frombytes(self.metadata.ToString())
+        return frombytes(self.metadata.ToString(), safe=True)
 
     def __eq__(self, other):
         try:
@@ -1012,7 +1012,8 @@ cdef class Field(_Weakrefable):
         return field, (self.name, self.type, self.nullable, self.metadata)
 
     def __str__(self):
-        return 'pyarrow.Field<{0}>'.format(frombytes(self.field.ToString()))
+        return 'pyarrow.Field<{0}>'.format(
+            frombytes(self.field.ToString(), safe=True))
 
     def __repr__(self):
         return self.__str__()
@@ -1574,7 +1575,7 @@ cdef class Schema(_Weakrefable):
                 )
             )
 
-        return frombytes(result)
+        return frombytes(result, safe=True)
 
     def _export_to_c(self, uintptr_t out_ptr):
         """