Add version token to error URL

the sqlalche.me redirector now supports the numerical version
code in the URL, e.g. /13/, /14/, /20/, etc., so that we can
redirect to the error codes for the appropriate version
of SQLAlchemy in use without going through the catch-all "latest"
link.   If a particular version of the docs is no longer on the
site, the redirect will revert to falling through the "latest"
link (which ultimately lands on the current release version,
/13/ at the time of this writing).

Change-Id: I3bb463fd6fb6c8767c95a57f3699aba715a9a72d

3 files changed, 35 insertions, 10 deletions

diff --git a/lib/sqlalchemy/__init__.py b/lib/sqlalchemy/__init__.py
index 27e9fd1c0..d52393d0b 100644
--- a/lib/sqlalchemy/__init__.py
+++ b/lib/sqlalchemy/__init__.py
@@ -142,5 +142,9 @@ def __go(lcls):
 
     _sa_util.preloaded.import_prefix("sqlalchemy")
 
+    from . import exc
+
+    exc._version_token = "".join(__version__.split(".")[0:2])
+
 
 __go(locals())
diff --git a/lib/sqlalchemy/exc.py b/lib/sqlalchemy/exc.py
index 92322fb90..491dde7b2 100644
--- a/lib/sqlalchemy/exc.py
+++ b/lib/sqlalchemy/exc.py
@@ -15,6 +15,8 @@ raised as a result of DBAPI exceptions are all subclasses of
 
 from .util import compat
 
+_version_token = None
+
 
 class SQLAlchemyError(Exception):
     """Generic error class."""
@@ -33,7 +35,7 @@ class SQLAlchemyError(Exception):
         else:
             return (
                 "(Background on this error at: "
-                "http://sqlalche.me/e/%s)" % (self.code,)
+                "http://sqlalche.me/e/%s/%s)" % (_version_token, self.code,)
             )
 
     def _message(self, as_unicode=compat.py3k):
diff --git a/test/base/test_except.py b/test/base/test_except.py
index be8c85a64..7ef077659 100644
--- a/test/base/test_except.py
+++ b/test/base/test_except.py
@@ -47,6 +47,17 @@ class SpecificIntegrityError(WrongNameError):
 
 
 class WrapTest(fixtures.TestBase):
+    def test_version_token(self):
+        assert sa_exceptions._version_token in (
+            "13",
+            "14",
+            "15",
+            "16",
+            "20",
+            "21",
+            "22",
+        )
+
     def _translating_dialect_fixture(self):
         d = default.DefaultDialect()
         d.dbapi_exception_translation_map = {
@@ -72,7 +83,8 @@ class WrapTest(fixtures.TestBase):
                 str(exc),
                 "(test.base.test_except.OperationalError) \n"
                 "[SQL: this is a message]\n"
-                "(Background on this error at: http://sqlalche.me/e/e3q8)",
+                "(Background on this error at: http://sqlalche.me/e/%s/e3q8)"
+                % sa_exceptions._version_token,
             )
 
     def test_tostring_with_newlines(self):
@@ -89,7 +101,8 @@ class WrapTest(fixtures.TestBase):
                 "(test.base.test_except.OperationalError) \n"
                 "[SQL: this is a message\nthis is the next line\n"
                 "the last line]\n"
-                "(Background on this error at: http://sqlalche.me/e/e3q8)",
+                "(Background on this error at: http://sqlalche.me/e/%s/e3q8)"
+                % sa_exceptions._version_token,
             )
 
     def test_statement_error_no_code(self):
@@ -122,7 +135,8 @@ class WrapTest(fixtures.TestBase):
                 "(sqlalchemy.exc.InvalidRequestError) hello\n"
                 "[SQL: select * from table]\n"
                 "[parameters: [{'x': 1}]]\n"
-                "(Background on this error at: http://sqlalche.me/e/abcd)",
+                "(Background on this error at: http://sqlalche.me/e/%s/abcd)"
+                % sa_exceptions._version_token,
             )
             eq_(err.args, ("(sqlalchemy.exc.InvalidRequestError) hello",))
 
@@ -133,7 +147,8 @@ class WrapTest(fixtures.TestBase):
         eq_(
             str(orig),
             "(2006, 'Test raise operational error')\n"
-            "(Background on this error at: http://sqlalche.me/e/dbapi)",
+            "(Background on this error at: http://sqlalche.me/e/%s/dbapi)"
+            % sa_exceptions._version_token,
         )
 
     def test_wrap_unicode_arg(self):
@@ -144,7 +159,7 @@ class WrapTest(fixtures.TestBase):
             compat.text_type(orig),
             compat.u(
                 "méil\n(Background on this error at: "
-                "http://sqlalche.me/e/dbapi)"
+                "http://sqlalche.me/e/%s/dbapi)" % sa_exceptions._version_token
             ),
         )
         eq_(orig.args, (u("méil"),))
@@ -217,7 +232,8 @@ class WrapTest(fixtures.TestBase):
                 "[SQL: this is a message]\n"
                 "[parameters: [{1: 1}, {1: 1}, {1: 1}, {1: 1}, {1: 1},"
                 " {1: 1}, {1: 1}, {1: 1}, {1: 1}, {1: 1}]]\n"
-                "(Background on this error at: http://sqlalche.me/e/e3q8)",
+                "(Background on this error at: http://sqlalche.me/e/%s/e3q8)"
+                % sa_exceptions._version_token,
             )
             eq_(
                 exc.args,
@@ -252,7 +268,8 @@ class WrapTest(fixtures.TestBase):
                 "{1: 1}, {1: 1}, {1: 1}, {1: 1}, {1: 1}, "
                 "{1: 1}, {1: 1}  ... displaying 10 of 11 total "
                 "bound parameter sets ...  {1: 1}, {1: 1}]]\n"
-                "(Background on this error at: http://sqlalche.me/e/e3q8)",
+                "(Background on this error at: http://sqlalche.me/e/%s/e3q8)"
+                % sa_exceptions._version_token,
             )
         try:
             raise sa_exceptions.DBAPIError.instance(
@@ -269,7 +286,8 @@ class WrapTest(fixtures.TestBase):
                 "[SQL: this is a message]\n"
                 "[parameters: [(1,), "
                 "(1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,)]]\n"
-                "(Background on this error at: http://sqlalche.me/e/e3q8)",
+                "(Background on this error at: http://sqlalche.me/e/%s/e3q8)"
+                % sa_exceptions._version_token,
             )
         try:
             raise sa_exceptions.DBAPIError.instance(
@@ -300,7 +318,8 @@ class WrapTest(fixtures.TestBase):
                 "(1,), (1,), (1,), (1,), (1,), (1,), (1,)  "
                 "... displaying 10 of 11 total bound "
                 "parameter sets ...  (1,), (1,)]]\n"
-                "(Background on this error at: http://sqlalche.me/e/e3q8)",
+                "(Background on this error at: http://sqlalche.me/e/%s/e3q8)"
+                % sa_exceptions._version_token,
             )
 
     def test_db_error_busted_dbapi(self):