Merge pull request #672 from paul-rouse/master

Fix #671 - revise handling of 'default null' in mysql
yesodweb · May 16, 2017 · 6968640 · 6968640
2 parents 04a7a15 + 84f7b49
commit 6968640
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diff --git a/persistent-mysql/ChangeLog.md b/persistent-mysql/ChangeLog.md
@@ -1,3 +1,7 @@
+##2.6.0.2
+
+Prevent spurious no-op migrations when `default=NULL` is specified - revised version [#672](https://github.com/yesodweb/persistent/pull/672) (which fixes bug [#671](https://github.com/yesodweb/persistent/issues/671) introduced by the earlier attempt [#641](https://github.com/yesodweb/persistent/pull/641))
+
 ## 2.6
 
 Compatibility for backend-specific upsert functionality.

diff --git a/persistent-mysql/Database/Persist/MySQL.hs b/persistent-mysql/Database/Persist/MySQL.hs
@@ -457,7 +457,7 @@ getColumns connectInfo getter def = do
     stmtIdClmn <- getter "SELECT COLUMN_NAME, \
                                  \IS_NULLABLE, \
                                  \DATA_TYPE, \
-                                 \IF(IS_NULLABLE='YES', COALESCE(COLUMN_DEFAULT, 'NULL'), COLUMN_DEFAULT) \
+                                 \COLUMN_DEFAULT \
                           \FROM INFORMATION_SCHEMA.COLUMNS \
                           \WHERE TABLE_SCHEMA = ? \
                             \AND TABLE_NAME   = ? \
@@ -473,7 +473,7 @@ getColumns connectInfo getter def = do
                                \CHARACTER_MAXIMUM_LENGTH, \
                                \NUMERIC_PRECISION, \
                                \NUMERIC_SCALE, \
-                               \IF(IS_NULLABLE='YES', COALESCE(COLUMN_DEFAULT, 'NULL'), COLUMN_DEFAULT) \
+                               \COLUMN_DEFAULT \
                         \FROM INFORMATION_SCHEMA.COLUMNS \
                         \WHERE TABLE_SCHEMA = ? \
                           \AND TABLE_NAME   = ? \
@@ -691,10 +691,12 @@ findAlters tblName allDefs col@(Column name isNull type_ def _defConstraintName
                 modType | showSqlType type_ maxLen False `ciEquals` showSqlType type_' maxLen' False && isNull == isNull' = []
                         | otherwise = [(name, Change col)]
                 -- Default value
+                -- Avoid DEFAULT NULL, since it is always unnecessary, and is an error for text/blob fields
                 modDef | def == def' = []
                        | otherwise   = case def of
                                          Nothing -> [(name, NoDefault)]
-                                         Just s -> [(name, Default $ T.unpack s)]
+                                         Just s -> if T.toUpper s == "NULL" then []
+                                                   else [(name, Default $ T.unpack s)]
             in ( refDrop ++ modType ++ modDef ++ refAdd
                , filter ((name /=) . cName) cols )
 
@@ -715,7 +717,9 @@ showColumn (Column n nu t def _defConstraintName maxLen ref) = concat
     , if nu then "NULL" else "NOT NULL"
     , case def of
         Nothing -> ""
-        Just s -> " DEFAULT " ++ T.unpack s
+        Just s -> -- Avoid DEFAULT NULL, since it is always unnecessary, and is an error for text/blob fields
+                  if T.toUpper s == "NULL" then ""
+                  else " DEFAULT " ++ T.unpack s
     , case ref of
         Nothing -> ""
         Just (s, _) -> " REFERENCES " ++ escapeDBName s

diff --git a/persistent-mysql/persistent-mysql.cabal b/persistent-mysql/persistent-mysql.cabal
@@ -1,5 +1,5 @@
 name:            persistent-mysql
-version:         2.6.0.1
+version:         2.6.0.2
 license:         MIT
 license-file:    LICENSE
 author:          Felipe Lessa <felipe.lessa@gmail.com>, Michael Snoyman