Fix for #218 (#485)

* fixes #218 by setting appropriate cypher variables

* tests for #218 fix

covers add, remove, and update (merge / update use the same translation function)

Author: michaeldgraham

src/translate.js

@@ -344,7 +344,9 @@ export const relationTypeFieldOnNodeType = ({
 }) => {
   let translation = '';
   if (innerSchemaTypeRelation.from === innerSchemaTypeRelation.to) {
-    translation = `${initial}${fieldName}: {${subSelection[0]}}${skipLimit} ${commaIfTail}`;
+    translation = `${initial}${fieldName}: {${
+      subSelection[0]
+    }}${skipLimit} ${commaIfTail}`;
   } else {
     const relationshipVariableName = `${nestedVariable}_relation`;
 
@@ -481,22 +483,25 @@ export const nodeTypeFieldOnRelationType = ({
   fieldArgs,
   cypherParams
 }) => {
-  const safeVariableName = safeVar(variableName);
   if (
     isRootSelection({
       selectionInfo: parentSelectionInfo,
       rootType: 'relationship'
     }) &&
     isRelationTypeDirectedField(fieldName)
   ) {
+    const nodeFieldVariableName = decideRootRelationshipTypeNodeVariable({
+      parentSelectionInfo,
+      fieldName
+    });
     const [mapProjection, labelPredicate] = buildMapProjection({
       schemaType: innerSchemaType,
       isObjectType: isObjectTypeField,
       isInterfaceType: isInterfaceTypeField,
       isUnionType: isUnionTypeField,
-      usesFragments,
-      safeVariableName,
+      safeVariableName: nodeFieldVariableName,
       subQuery: subSelection[0],
+      usesFragments,
       schemaTypeFields,
       derivedTypeMap,
       resolveInfo
@@ -544,6 +549,19 @@ export const nodeTypeFieldOnRelationType = ({
   });
 };
 
+const decideRootRelationshipTypeNodeVariable = ({
+  parentSelectionInfo = {},
+  fieldName
+}) => {
+  const fromVariable = parentSelectionInfo.from;
+  const toVariable = parentSelectionInfo.to;
+  // assume incoming
+  let variableName = safeVar(fromVariable);
+  // else set as outgoing
+  if (fieldName === 'to') variableName = safeVar(toVariable);
+  return variableName;
+};
+
 const relationTypeMutationPayloadField = ({
   initial,
   fieldName,
@@ -871,7 +889,9 @@ export const neo4jType = ({
   return {
     initial: `${initial}${fieldName}: ${
       fieldIsArray
-        ? `reduce(a = [], INSTANCE IN ${variableName}.${fieldName} | a + {${subSelection[0]}})${commaIfTail}`
+        ? `reduce(a = [], INSTANCE IN ${variableName}.${fieldName} | a + {${
+            subSelection[0]
+          }})${commaIfTail}`
         : usesTemporalOrdering
         ? `${safeVariableName}.${fieldName}${commaIfTail}`
         : `{${subSelection[0]}}${commaIfTail}`
@@ -1816,7 +1836,6 @@ const relationshipCreate = ({
       to: toVar,
       variableName: lowercased
     },
-    variableName: schemaType.name === fromType ? `${toVar}` : `${fromVar}`,
     cypherParams: getCypherParams(context)
   });
   params = { ...preparedParams, ...subParams };
@@ -1942,7 +1961,6 @@ const relationshipDelete = ({
       from: `_${fromVar}`,
       to: `_${toVar}`
     },
-    variableName: schemaType.name === fromType ? `_${toVar}` : `_${fromVar}`,
     cypherParams: getCypherParams(context)
   });
   params = { ...params, ...subParams };
@@ -2068,7 +2086,6 @@ const relationshipMergeOrUpdate = ({
         to: toVar,
         variableName: lowercased
       },
-      variableName: schemaType.name === fromType ? `${toVar}` : `${fromVar}`,
       cypherParams: getCypherParams(context)
     });
     let cypherOperation = '';

test/unit/cypherTest.test.js

@@ -778,6 +778,39 @@ test('Add relationship mutation', t => {
   );
 });
 
+test('Add relationship mutation and query only outgoing nodes', t => {
+  const graphQLQuery = `mutation someMutation {
+    AddMovieGenres(
+      from: { movieId: "123" },
+      to: { name: "Action" }
+    ) {
+      to {
+        name
+      }
+    }
+  }`,
+    expectedCypherQuery = `
+      MATCH (\`movie_from\`:\`Movie\`${ADDITIONAL_MOVIE_LABELS} {movieId: $from.movieId})
+      MATCH (\`genre_to\`:\`Genre\` {name: $to.name})
+      CREATE (\`movie_from\`)-[\`in_genre_relation\`:\`IN_GENRE\`]->(\`genre_to\`)
+      RETURN \`in_genre_relation\` { to: \`genre_to\` { .name }  } AS \`_AddMovieGenresPayload\`;
+    `;
+
+  t.plan(1);
+  return augmentedSchemaCypherTestRunner(
+    t,
+    graphQLQuery,
+    {
+      from: { movieId: '123' },
+      to: { name: 'Action' },
+      first: -1,
+      offset: 0
+    },
+    expectedCypherQuery,
+    {}
+  );
+});
+
 test('Merge relationship mutation', t => {
   const graphQLQuery = `mutation someMutation {
     MergeMovieGenres(
@@ -1053,6 +1086,63 @@ test('Update relationship mutation with relationship property', t => {
   );
 });
 
+test('Update relationship mutation with relationship property and query only outgoing nodes', t => {
+  const graphQLQuery = `mutation someMutation {
+    UpdateUserRated(
+      from: { userId: "123" }
+      to: { movieId: "2kljghd" }
+      data: {
+        rating: 1
+        location: { longitude: 3.0, latitude: 4.5, height: 12.5 }
+      }
+    ) {
+      to {
+        _id
+        movieId
+        title
+        ratings {
+          rating
+          User {
+            _id
+            userId
+            name
+          }
+        }
+      }
+      rating
+    }
+  }
+  `,
+    expectedCypherQuery = `
+      MATCH (\`user_from\`:\`User\` {userId: $from.userId})
+      MATCH (\`movie_to\`:\`Movie\`${ADDITIONAL_MOVIE_LABELS} {movieId: $to.movieId})
+      MATCH (\`user_from\`)-[\`rated_relation\`:\`RATED\`]->(\`movie_to\`)
+      SET \`rated_relation\` += {rating:$data.rating,location: point($data.location)} 
+      RETURN \`rated_relation\` { to: \`movie_to\` {_id: ID(\`movie_to\`), .movieId , .title ,ratings: [(\`movie_to\`)<-[\`movie_to_ratings_relation\`:\`RATED\`]-(:\`User\`) | movie_to_ratings_relation { .rating ,User: head([(:\`Movie\`${ADDITIONAL_MOVIE_LABELS})<-[\`movie_to_ratings_relation\`]-(\`movie_to_ratings_User\`:\`User\`) | movie_to_ratings_User {_id: ID(\`movie_to_ratings_User\`), .userId , .name }]) }] } , .rating  } AS \`_UpdateUserRatedPayload\`;
+    `;
+
+  t.plan(1);
+  return augmentedSchemaCypherTestRunner(
+    t,
+    graphQLQuery,
+    {
+      from: { userId: '123' },
+      to: { movieId: '2kljghd' },
+      data: {
+        rating: 1,
+        location: {
+          longitude: 3.0,
+          latitude: 4.5,
+          height: 12.5
+        }
+      },
+      first: -1,
+      offset: 0
+    },
+    expectedCypherQuery
+  );
+});
+
 test('Add reflexive relationship mutation with relationship property', t => {
   const graphQLQuery = `mutation {
     AddUserFriends(
@@ -1755,6 +1845,41 @@ test('Remove relationship mutation', t => {
   );
 });
 
+test('Remove relationship mutation and query only outgoing nodes', t => {
+  const graphQLQuery = `mutation someMutation {
+    RemoveMovieGenres(
+      from: { movieId: "123" },
+      to: { name: "Action" }
+    ) {
+      to {
+        _id
+        name
+      }
+    }
+  }`,
+    expectedCypherQuery = `
+      MATCH (\`movie_from\`:\`Movie\`${ADDITIONAL_MOVIE_LABELS} {movieId: $from.movieId})
+      MATCH (\`genre_to\`:\`Genre\` {name: $to.name})
+      OPTIONAL MATCH (\`movie_from\`)-[\`movie_fromgenre_to\`:\`IN_GENRE\`]->(\`genre_to\`)
+      DELETE \`movie_fromgenre_to\`
+      WITH COUNT(*) AS scope, \`movie_from\` AS \`_movie_from\`, \`genre_to\` AS \`_genre_to\`
+      RETURN {to: \`_genre_to\` {_id: ID(\`_genre_to\`), .name } } AS \`_RemoveMovieGenresPayload\`;
+    `;
+
+  t.plan(1);
+  return augmentedSchemaCypherTestRunner(
+    t,
+    graphQLQuery,
+    {
+      from: { movieId: '123' },
+      to: { name: 'Action' },
+      first: -1,
+      offset: 0
+    },
+    expectedCypherQuery
+  );
+});
+
 test('Remove reflexive relationship mutation', t => {
   const graphQLQuery = `mutation {
     RemoveUserFriends(