error message for Lookup

Thr proposed change will provide the user with the target Enum Class name as well as up to four possible enum values when a LookupError is raised in the Enum Class.

A user requested that the enum name and possible values are included to the LookupError message to make debugging easier. The criteria included using ellipses for Enums containing more than four values and using ellipses for enum values that were greater than a certain number of characters (for this resolution the limit is 11 characters).

This pull request is:

- [ ] A documentation / typographical error fix
	- Good to go, no issue or tests are needed
- [X ] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**
Fixes: #4733
Closes: #5490
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5490
Pull-request-sha: 55e76f2ae796b59b7de157cfaae5235dffa359cb

Change-Id: I4541f9efed1c05401587a413e9e748d46938bcd1

diff --git a/doc/build/changelog/unreleased_13/4733.rst b/doc/build/changelog/unreleased_13/4733.rst
new file mode 100644 (file)
index 0000000..fb85800
--- /dev/null
+++ b/doc/build/changelog/unreleased_13/4733.rst
@@ -0,0 +1,8 @@
+.. change::
+    :tags: bug, datatypes, sql
+    :tickets: 4733
+
+    The ``LookupError`` message will now provide the user with up to four
+    possible values that a column is constrained to via the :class:`.Enum`.
+    Values longer than 11 characters will be truncated and replaced with
+    ellipses. Pull request courtesy Ramon Williams.

diff --git a/lib/sqlalchemy/sql/sqltypes.py b/lib/sqlalchemy/sql/sqltypes.py
index 64663a6b01724075cd3024ac556cded85791f68b..af582921637170cd86308c140c643a1b3ea19a0a 100644 (file)
--- a/lib/sqlalchemy/sql/sqltypes.py
+++ b/lib/sqlalchemy/sql/sqltypes.py
@@ -38,6 +38,7 @@ from .. import inspection
 from .. import processors
 from .. import util
 from ..util import compat
+from ..util import langhelpers
 from ..util import pickle
 
 
@@ -1555,7 +1556,13 @@ class Enum(Emulated, String, SchemaType):
             else:
                 util.raise_(
                     LookupError(
-                        '"%s" is not among the defined enum values' % elem
+                        "'%s' is not among the defined enum values. "
+                        "Enum name: %s. Possible values: %s"
+                        % (
+                            elem,
+                            self.name,
+                            langhelpers.repr_tuple_names(self.enums),
+                        )
                     ),
                     replace_context=err,
                 )
@@ -1579,7 +1586,13 @@ class Enum(Emulated, String, SchemaType):
         except KeyError as err:
             util.raise_(
                 LookupError(
-                    '"%s" is not among the defined enum values' % elem
+                    "'%s' is not among the defined enum values. "
+                    "Enum name: %s. Possible values: %s"
+                    % (
+                        elem,
+                        self.name,
+                        langhelpers.repr_tuple_names(self.enums),
+                    )
                 ),
                 replace_context=err,
             )

diff --git a/lib/sqlalchemy/util/langhelpers.py b/lib/sqlalchemy/util/langhelpers.py
index cec54542a9e852dfc237a3f97948d60fd7b15c2b..e8abf3130badf82efa2214c2abd98da847d59ff0 100644 (file)
--- a/lib/sqlalchemy/util/langhelpers.py
+++ b/lib/sqlalchemy/util/langhelpers.py
@@ -1735,3 +1735,17 @@ def inject_param_text(doctext, inject_params):
         lines.append(line)
 
     return "\n".join(lines)
+
+
+def repr_tuple_names(names):
+    """ Trims a list of strings from the middle and return a string of up to
+        four elements. Strings greater than 11 characters will be truncated"""
+    if len(names) == 0:
+        return None
+    flag = len(names) <= 4
+    names = names[0:4] if flag else names[0:3] + names[-1:]
+    res = ["%s.." % name[:11] if len(name) > 11 else name for name in names]
+    if flag:
+        return ", ".join(res)
+    else:
+        return "%s, ..., %s" % (", ".join(res[0:3]), res[-1])

diff --git a/test/sql/test_types.py b/test/sql/test_types.py
index fac9fd1399aaa224b1eda90fe46b562592371642..30309046e9ed797701b227cd39db3a4cb331538c 100644 (file)
--- a/test/sql/test_types.py
+++ b/test/sql/test_types.py
@@ -1452,14 +1452,16 @@ class EnumTest(AssertsCompiledSQL, fixtures.TablesTest):
         eq_(bind_processor("foo"), "foo")
         assert_raises_message(
             LookupError,
-            '"5" is not among the defined enum values',
+            "'5' is not among the defined enum values. Enum name: someenum. "
+            "Possible values: one, two, three, ..., BMember",
             bind_processor,
             5,
         )
 
         assert_raises_message(
             LookupError,
-            '"foo" is not among the defined enum values',
+            "'foo' is not among the defined enum values. Enum name: someenum. "
+            "Possible values: one, two, three, ..., BMember",
             bind_processor_validates,
             "foo",
         )
@@ -1469,7 +1471,8 @@ class EnumTest(AssertsCompiledSQL, fixtures.TablesTest):
         eq_(result_processor("one"), self.one)
         assert_raises_message(
             LookupError,
-            '"foo" is not among the defined enum values',
+            "'foo' is not among the defined enum values. Enum name: someenum. "
+            "Possible values: one, two, three, ..., BMember",
             result_processor,
             "foo",
         )
@@ -1484,14 +1487,16 @@ class EnumTest(AssertsCompiledSQL, fixtures.TablesTest):
 
         assert_raises_message(
             LookupError,
-            '"5" is not among the defined enum values',
+            "'5' is not among the defined enum values. Enum name: someenum. "
+            "Possible values: one, two, three, ..., BMember",
             literal_processor,
             5,
         )
 
         assert_raises_message(
             LookupError,
-            '"foo" is not among the defined enum values',
+            "'foo' is not among the defined enum values. Enum name: someenum. "
+            "Possible values: one, two, three, ..., BMember",
             validate_literal_processor,
             "foo",
         )
@@ -1508,14 +1513,16 @@ class EnumTest(AssertsCompiledSQL, fixtures.TablesTest):
         eq_(bind_processor("foo"), "foo")
         assert_raises_message(
             LookupError,
-            '"5" is not among the defined enum values',
+            "'5' is not among the defined enum values. Enum name: None. "
+            "Possible values: one, two",
             bind_processor,
             5,
         )
 
         assert_raises_message(
             LookupError,
-            '"foo" is not among the defined enum values',
+            "'foo' is not among the defined enum values. Enum name: None. "
+            "Possible values: one, two",
             bind_processor_validates,
             "foo",
         )
@@ -1525,7 +1532,8 @@ class EnumTest(AssertsCompiledSQL, fixtures.TablesTest):
         eq_(result_processor("one"), "one")
         assert_raises_message(
             LookupError,
-            '"foo" is not among the defined enum values',
+            "'foo' is not among the defined enum values. Enum name: None. "
+            "Possible values: one, two",
             result_processor,
             "foo",
         )
@@ -1538,18 +1546,45 @@ class EnumTest(AssertsCompiledSQL, fixtures.TablesTest):
         eq_(literal_processor("foo"), "'foo'")
         assert_raises_message(
             LookupError,
-            '"5" is not among the defined enum values',
+            "'5' is not among the defined enum values. Enum name: None. "
+            "Possible values: one, two",
             literal_processor,
             5,
         )
 
         assert_raises_message(
             LookupError,
-            '"foo" is not among the defined enum values',
+            "'foo' is not among the defined enum values. Enum name: None. "
+            "Possible values: one, two",
             validate_literal_processor,
             "foo",
         )
 
+    def test_enum_raise_lookup_ellipses(self):
+        type_ = Enum("one", "twothreefourfivesix", "seven", "eight")
+        bind_processor = type_.bind_processor(testing.db.dialect)
+
+        eq_(bind_processor("one"), "one")
+        assert_raises_message(
+            LookupError,
+            "'5' is not among the defined enum values. Enum name: None. "
+            "Possible values: one, twothreefou.., seven, eight",
+            bind_processor,
+            5,
+        )
+
+    def test_enum_raise_lookup_none(self):
+        type_ = Enum()
+        bind_processor = type_.bind_processor(testing.db.dialect)
+
+        assert_raises_message(
+            LookupError,
+            "'5' is not among the defined enum values. Enum name: None. "
+            "Possible values: None",
+            bind_processor,
+            5,
+        )
+
     def test_validators_not_in_like_roundtrip(self, connection):
         enum_table = self.tables["non_native_enum_table"]
 
@@ -1745,7 +1780,8 @@ class EnumTest(AssertsCompiledSQL, fixtures.TablesTest):
             )
             assert_raises_message(
                 LookupError,
-                '"four" is not among the defined enum values',
+                "'four' is not among the defined enum values. "
+                "Enum name: None. Possible values: one, two, three",
                 conn.scalar,
                 select([self.tables.non_native_enum_table.c.someotherenum]),
             )