Fixing m2m skips from cycle detection (#2114)

In this case, if any of the models had a many to many field, we just
stopped the cycle checks at that point, leading to a wrong error.

libs/datamodel/core/src/transform/ast_to_dml/validate.rs

@@ -416,7 +416,7 @@ impl<'a> Validator<'a> {
 
             // skip many-to-many
             if field.is_list() && related_field.is_list() {
-                return;
+                continue;
             }
 
             // we skipped many-to-many relations, so one of the sides either has

libs/datamodel/core/tests/attributes/relations/referential_actions.rs

@@ -803,59 +803,66 @@ fn sql_server_cascading_cyclic_hop_over_table_relations() {
 fn sql_server_cascading_cyclic_hop_over_backrelation() {
     let dml = indoc! {
         r#"
-        datasource db {
+        datasource test {
             provider = "sqlserver"
-            url = "sqlserver://"
+            url      = "sqlserver://localhost:1433;database=master;user=SA;password=<YourStrong@Passw0rd>;trustServerCertificate=true"
         }
 
         generator client {
-            provider = "prisma-client-js"
-            previewFeatures = ["referentialActions", "microsoftSqlServer"]
+            provider        = "prisma-client-js"
+            previewFeatures = ["microsoftSqlServer", "referentialActions"]
         }
 
-        model A {
-            id     Int  @id @default(autoincrement())
-            bId    Int
-            b      B    @relation(fields: [bId], references: [id])
-            cs     C[]
+        model User {
+            id        Int       @id @default(autoincrement())
+            comments  Comment[]
+            posts     Post[]
         }
 
-        model B {
-            id     Int  @id @default(autoincrement())
-            as     A[]
-            cs     C[]
+        model Post {
+            id        Int       @id @default(autoincrement())
+            authorId  Int
+            author    User      @relation(fields: [authorId], references: [id])
+            comments  Comment[]
+            tags      Tag[]     @relation("TagToPost")
         }
 
-        model C {
-            id     Int @id @default(autoincrement())
-            aId    Int
-            bId    Int
-            a      A   @relation(fields: [aId], references: [id])
-            b      B   @relation(fields: [bId], references: [id])
+        model Comment {
+            id          Int      @id @default(autoincrement())
+            writtenById Int
+            postId      Int
+            writtenBy   User     @relation(fields: [writtenById], references: [id])
+            post        Post     @relation(fields: [postId], references: [id])
+        }
+
+        model Tag {
+            id    Int    @id @default(autoincrement())
+            tag   String @unique
+            posts Post[] @relation("TagToPost")
         }
     "#};
 
     let expect = expect![[r#"
         error: Error parsing attribute "@relation": Reference causes a cycle or multiple cascade paths. One of the @relation attributes in this cycle must have `onDelete` and `onUpdate` referential actions set to `NoAction`. Implicit default `onUpdate` value: `Cascade`.
-          [1;94m-->[0m  [4mschema.prisma:14[0m
+          [1;94m-->[0m  [4mschema.prisma:20[0m
            | 
-        [1;94m13 | [0m    bId    Int
-        [1;94m14 | [0m    [1;91mb      B    @relation(fields: [bId], references: [id])[0m
-        [1;94m15 | [0m    cs     C[]
+        [1;94m19 | [0m    authorId  Int
+        [1;94m20 | [0m    [1;91mauthor    User      @relation(fields: [authorId], references: [id])[0m
+        [1;94m21 | [0m    comments  Comment[]
            | 
         error: Error parsing attribute "@relation": Reference causes a cycle or multiple cascade paths. One of the @relation attributes in this cycle must have `onDelete` and `onUpdate` referential actions set to `NoAction`. Implicit default `onUpdate` value: `Cascade`.
-          [1;94m-->[0m  [4mschema.prisma:28[0m
+          [1;94m-->[0m  [4mschema.prisma:29[0m
            | 
-        [1;94m27 | [0m    bId    Int
-        [1;94m28 | [0m    [1;91ma      A   @relation(fields: [aId], references: [id])[0m
-        [1;94m29 | [0m    b      B   @relation(fields: [bId], references: [id])
+        [1;94m28 | [0m    postId      Int
+        [1;94m29 | [0m    [1;91mwrittenBy   User     @relation(fields: [writtenById], references: [id])[0m
+        [1;94m30 | [0m    post        Post     @relation(fields: [postId], references: [id])
            | 
         error: Error parsing attribute "@relation": Reference causes a cycle or multiple cascade paths. One of the @relation attributes in this cycle must have `onDelete` and `onUpdate` referential actions set to `NoAction`. Implicit default `onUpdate` value: `Cascade`.
-          [1;94m-->[0m  [4mschema.prisma:29[0m
+          [1;94m-->[0m  [4mschema.prisma:30[0m
            | 
-        [1;94m28 | [0m    a      A   @relation(fields: [aId], references: [id])
-        [1;94m29 | [0m    [1;91mb      B   @relation(fields: [bId], references: [id])[0m
-        [1;94m30 | [0m}
+        [1;94m29 | [0m    writtenBy   User     @relation(fields: [writtenById], references: [id])
+        [1;94m30 | [0m    [1;91mpost        Post     @relation(fields: [postId], references: [id])[0m
+        [1;94m31 | [0m}
            | 
     "#]];