Add support to exclude specific relationships. Update docs (#14)

* Add support to exclude specific relationships. Update docs

* Update var name

Author: chrispenny

README.md

@@ -7,6 +7,8 @@ Generate a YAML fixture from DataObjects
 - [Warnings](#warnings)
 - [Dev task](#dev-task)
 - [General usage](#general-usage)
+- [Set a maximum depth to export](#set-a-maximum-depth-to-export)
+- [Excluding relationships from export](#excluding-relationships-from-export)
 - [Excluding classes from export](#excluding-classes-from-export)
 - [Common errors](#common-errors)
 - [Supported relationships](#supported-relationships)
@@ -86,6 +88,17 @@ $fixture = Director::baseFolder() . '/app/resources/fixture.yml';
 file_put_contents($fixture, $service->outputFixture());
 ```
 
+## Set a maximum depth to export
+
+If you are having issues with "nesting level of '256' reached", then one option is to set a maximum depth that the
+Service will attempt to export.
+
+```php
+// Instantiate the Service.
+$service = new FixtureService();
+$service->setAllowedDepth(2);
+```
+
 ## Excluding classes from export
 
 There might be some classes (like Members?) that you don't want to include in your fixture. The manifest will check
@@ -117,8 +130,46 @@ SilverStripe\Security\Member:
   exclude_from_fixture_relationships: 0
 ```
 
+## Excluding relationships from export
+
+Similar to excluding classes, there might be some specific relationships on specific classes that you want to exclude.
+Perhaps you have identified a looping relationship, and you would like to exclude one of them to make things
+predictable, or perhaps it's just a relationship you don't need in your fixtures.
+
+You can exclude specific relationships by adding `excluded_fixture_relationships` to the desired class.
+
+`excluded_fixture_relationships` accepts an array of **relationship names**.
+
+EG:
+```php
+class MyModel extends DataObject
+{
+    private static $has_one = [
+        'FeatureImage' => Image::class,
+    ];
+}
+```
+
+```yaml
+App\Models\MyModel:
+  excluded_fixture_relationships:
+    - FeatureImage
+```
+
 ## Common errors
 
+### Nesting level of '256' reached
+
+Above are three options that you can use to attempt to reduce this.
+
+- [Set a maximum depth to export](#set-a-maximum-depth-to-export)
+- [Excluding relationships from export](#excluding-relationships-from-export)
+- [Excluding classes from export](#excluding-classes-from-export)
+
+I would recommend that you begin by exluding classes that you don't need for your export, then move to excluding
+specific relationships that might be causing deep levels of nested relationships, and finally, if those fail, you can
+set a max depth.
+
 ### DataObject::get() cannot query non-subclass DataObject directly
 
 You might see this error if you have a relationship being defined as simply `DataObject::class`, EG:

src/Manifest/RelationshipManifest.php

@@ -5,6 +5,7 @@
 use ChrisPenny\DataObjectToFixture\Helper\KahnSorter;
 use ChrisPenny\DataObjectToFixture\ORM\Group;
 use Exception;
+use SilverStripe\Core\Config\Config;
 
 class RelationshipManifest
 {
@@ -14,6 +15,11 @@ class RelationshipManifest
      */
     private $relationships = [];
 
+    /**
+     * @var array
+     */
+    private $excludedRelationships = [];
+
     /**
      * @return array
      */
@@ -27,11 +33,24 @@ public function getRelationships(): array
      */
     public function addGroup(Group $group): void
     {
+        // If we've added this group to relationships already, then we have everything we need
         if (array_key_exists($group->getClassName(), $this->relationships)) {
             return;
         }
 
+        // Add this group as a new relationship
         $this->relationships[$group->getClassName()] = [];
+
+        // Check to see if this class has any relationships that it wants to exclude as we process it
+        $excludes = Config::inst()->get($group->getClassName(), 'excluded_fixture_relationships');
+
+        // No it doesn't, so we can just return here
+        if (!$excludes) {
+            return;
+        }
+
+        // Add the list of relationships to exclude from our fixtures
+        $this->excludedRelationships[$group->getClassName()] = $excludes;
     }
 
     /**
@@ -75,11 +94,38 @@ public function removeRelationship(string $fromClass, string $toClass): void
         unset($this->relationships[$toClass][$key]);
     }
 
+    /**
+     * @param string $className
+     * @param string $relationshipName
+     * @return bool
+     */
+    public function shouldExcludeRelationship(string $className, string $relationshipName): bool
+    {
+        if (!array_key_exists($className, $this->excludedRelationships)) {
+            return false;
+        }
+
+        $exclusions = $this->excludedRelationships[$className];
+
+        return in_array($relationshipName, $exclusions);
+    }
+
+    /**
+     * @return array
+     */
     public function getPrioritisedOrder(): array
     {
         $kahnSorter = new KahnSorter($this->getRelationships());
 
         return $kahnSorter->sort();
     }
 
+    /**
+     * @return array
+     */
+    public function getExcludedRelationships(): array
+    {
+        return $this->excludedRelationships;
+    }
+
 }

src/Service/FixtureService.php

@@ -174,6 +174,31 @@ public function getWarnings(): array
         return $this->warnings;
     }
 
+    /**
+     * @return int
+     */
+    public function getAllowedDepth(): ?int
+    {
+        return $this->allowedDepth;
+    }
+
+    /**
+     * @param int $allowedDepth
+     * @return FixtureService
+     */
+    public function setAllowedDepth(int $allowedDepth = null): FixtureService
+    {
+        if ($allowedDepth === 0) {
+            $this->addWarning('You set an allowed depth of 0. We have assumed you meant 1.');
+
+            $allowedDepth = 1;
+        }
+
+        $this->allowedDepth = $allowedDepth;
+
+        return $this;
+    }
+
     /**
      * @return array
      */
@@ -271,9 +296,18 @@ protected function addDataObjectHasOneFields(DataObject $dataObject, int $curren
             }
 
             // This class has requested that it not be included in relationship maps.
-            $exclude = Config::inst()->get($relationFieldName, 'exclude_from_fixture_relationships');
+            $excludeClass = Config::inst()->get($relationClassName, 'exclude_from_fixture_relationships');
 
-            if ($exclude) {
+            if ($excludeClass) {
+                continue;
+            }
+
+            $excludeRelationship = $this->relationshipManifest->shouldExcludeRelationship(
+                $dataObject->ClassName,
+                $fieldName
+            );
+
+            if ($excludeRelationship) {
                 continue;
             }
 
@@ -385,9 +419,18 @@ protected function addDataObjectHasManyFields(DataObject $dataObject, int $curre
             $schema->getRemoteJoinField($dataObject->ClassName, $relationFieldName, 'has_many');
 
             // This class has requested that it not be included in relationship maps.
-            $exclude = Config::inst()->get($cleanRelationshipClassName, 'exclude_from_fixture_relationships');
+            $excludeClass = Config::inst()->get($cleanRelationshipClassName, 'exclude_from_fixture_relationships');
 
-            if ($exclude) {
+            if ($excludeClass) {
+                continue;
+            }
+
+            $excludeRelationship = $this->relationshipManifest->shouldExcludeRelationship(
+                $dataObject->ClassName,
+                $relationFieldName
+            );
+
+            if ($excludeRelationship) {
                 continue;
             }
 
@@ -662,9 +705,10 @@ protected function removeLoopingRelationships(array $parentage, array $toClasses
                     $this->relationshipManifest->removeRelationship($toClass, $loopingRelationship);
 
                     $this->addWarning(sprintf(
-                        'A relationships was removed between "%s" and "%s". This occurs if we have detected a loop'
-                            . '. Until belongs_to relationships are supported in fixtures, you might not be able to rely on'
-                            . ' fixtures generated to have the appropriate priority order',
+                        'A relationships was removed between "%s" and "%s". This occurs if we have detected a'
+                            . ' loop . Until belongs_to relationships are supported in fixtures, you might not be able'
+                            . ' to rely on fixtures generated to have the appropriate priority order. You might want to'
+                            . ' consider adding one of these relationships to `excluded_fixture_relationships`.',
                         $loopingRelationship,
                         $toClass
                     ));
@@ -711,29 +755,4 @@ protected function addWarning(string $message): void
         $this->warnings[] = $message;
     }
 
-    /**
-     * @return int
-     */
-    public function getAllowedDepth(): ?int
-    {
-        return $this->allowedDepth;
-    }
-
-    /**
-     * @param int $allowedDepth
-     * @return FixtureService
-     */
-    public function setAllowedDepth(int $allowedDepth = null): FixtureService
-    {
-        if ($allowedDepth === 0) {
-            $this->addWarning('You set an allowed depth of 0. We have assumed you meant 1.');
-
-            $allowedDepth = 1;
-        }
-
-        $this->allowedDepth = $allowedDepth;
-
-        return $this;
-    }
-
 }