add more context to the StrategyViolatesRelationVariableMergeError fo…

…r debugging #364
agentm · Jan 9, 2024 · 92ccd19 · 92ccd19
1 parent 4b0200a
commit 92ccd19
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Showing 3 changed files with 9 additions and 5 deletions.
diff --git a/src/lib/ProjectM36/Error.hs b/src/lib/ProjectM36/Error.hs
@@ -131,7 +131,7 @@ data MergeError = SelectedHeadMismatchMergeError |
                   InvalidMergeStrategyError MergeStrategy | -- this is an internal coding error
                   DisconnectedTransactionNotAMergeHeadError TransactionId |
                   StrategyViolatesComponentMergeError | --failed merge in inc deps, relvars, etc.
-                  StrategyViolatesRelationVariableMergeError |
+                  StrategyViolatesRelationVariableMergeError (Maybe RelationalError) |
                   StrategyViolatesTypeConstructorMergeError |
                   StrategyViolatesRegisteredQueryMergeError [RegisteredQueryName]
                   deriving (Show, Eq, Generic, Typeable)

diff --git a/src/lib/ProjectM36/TransactionGraph/Merge.hs b/src/lib/ProjectM36/TransactionGraph/Merge.hs
@@ -12,6 +12,7 @@ import qualified Data.Text as T
 
 data MergePreference = PreferFirst | PreferSecond | PreferNeither
 
+
 -- Check for overlapping keys. If the values differ, try a preference resolution
 unionMergeMaps :: (Ord k, Eq a) => MergePreference -> M.Map k a -> M.Map k a -> Either MergeError (M.Map k a)
 unionMergeMaps prefer mapA mapB = case prefer of
@@ -26,14 +27,14 @@ unionMergeMaps prefer mapA mapB = case prefer of
 unionMergeRelation :: MergePreference -> GraphRefRelationalExpr -> GraphRefRelationalExpr -> GraphRefRelationalExprM GraphRefRelationalExpr
 unionMergeRelation prefer relA relB = do
   let unioned = Union relA relB
-      mergeErr = MergeTransactionError StrategyViolatesRelationVariableMergeError
+      mergeErr = MergeTransactionError . StrategyViolatesRelationVariableMergeError
       preferredRelVar =
         case prefer of
           PreferFirst -> pure relA
           PreferSecond -> pure relB
-          PreferNeither -> throwError mergeErr
+          PreferNeither -> throwError (mergeErr Nothing)
       handler AttributeNamesMismatchError{} = preferredRelVar
-      handler _err' = throwError mergeErr
+      handler err = throwError (mergeErr (Just err))
   --typecheck first?
   (evalGraphRefRelationalExpr unioned >> pure (Union relA relB)) `catchError` handler
 

diff --git a/test/TransactionGraph/Merge.hs b/test/TransactionGraph/Merge.hs
@@ -247,7 +247,10 @@ testUnionMergeStrategy = TestCase $ do
           gfEnv' = freshGraphRefRelationalExprEnv Nothing graph'''
       case failingMerge of
         Right _ -> assertFailure "expected merge failure"
-        Left err -> assertEqual "merge failure" err (MergeTransactionError StrategyViolatesRelationVariableMergeError)
+        Left err ->
+          let expectedErr = MergeTransactionError (StrategyViolatesRelationVariableMergeError (Just EmptyAttributesError))
+          in
+          assertEqual "merge failure" err expectedErr
 
 -- test that a merge will fail if a constraint is violated
 testUnionMergeIncDepViolation :: Test