Merge pull request #29 from colinodell/throw-exception-on-missing-key

Throw exception when accessing non-existent key paths and not providing a default value

Author: simensen

README.md

@@ -41,6 +41,13 @@ $data->has('a.b.c');
 
 // false
 $data->has('a.b.d.j');
+
+
+// 'some-default-value'
+$data->get('some.path.that.does.not.exist', 'some-default-value');
+
+// throws a MissingPathException because no default was given
+$data->get('some.path.that.does.not.exist');
 ```
 
 A more concrete example:

src/Data.php

@@ -16,6 +16,7 @@
 use ArrayAccess;
 use Dflydev\DotAccessData\Exception\DataException;
 use Dflydev\DotAccessData\Exception\InvalidPathException;
+use Dflydev\DotAccessData\Exception\MissingPathException;
 
 /**
  * @implements ArrayAccess<string, mixed>
@@ -116,16 +117,21 @@ public function remove(string $key): void
      */
     public function get(string $key, $default = null)
     {
+        /** @psalm-suppress ImpureFunctionCall */
+        $hasDefault = \func_num_args() > 1;
+
         $currentValue = $this->data;
         $keyPath = self::keyToPathArray($key);
 
         foreach ($keyPath as $currentKey) {
-            if (!isset($currentValue[$currentKey])) {
-                return $default;
-            }
-            if (!is_array($currentValue)) {
-                return $default;
+            if (!is_array($currentValue) || !isset($currentValue[$currentKey])) {
+                if ($hasDefault) {
+                    return $default;
+                }
+
+                throw new MissingPathException($key, sprintf('No data exists at the given path: "%s"', self::formatPath($keyPath)));
             }
+
             $currentValue = $currentValue[$currentKey];
         }
 
@@ -208,7 +214,7 @@ public function offsetExists($key)
      */
     public function offsetGet($key)
     {
-        return $this->get($key);
+        return $this->get($key, null);
     }
 
     /**

src/DataInterface.php

@@ -58,14 +58,16 @@ public function remove(string $key): void;
     /**
      * Get the raw value for a key
      *
-     * If the key does not exist, the provided default value (or null) will be returned instead.
+     * If the key does not exist, an optional default value can be returned instead.
+     * If no default is provided then an exception will be thrown instead.
      *
      * @param string $key
      * @param mixed $default
      *
      * @return mixed
      *
      * @throws InvalidPathException if the given key is empty
+     * @throws InvalidPathException if the given key does not exist and no default value was given
      *
      * @psalm-mutation-free
      */

src/Exception/MissingPathException.php

@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is a part of dflydev/dot-access-data.
+ *
+ * (c) Dragonfly Development Inc.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Dflydev\DotAccessData\Exception;
+
+use Throwable;
+
+/**
+ * Thrown when trying to access a path that does not exist
+ */
+class MissingPathException extends DataException
+{
+    /** @var string */
+    protected $path;
+
+    public function __construct(string $path, string $message = '', int $code = 0, Throwable $previous = null)
+    {
+        $this->path = $path;
+
+        parent::__construct($message, $code, $previous);
+    }
+
+    public function getPath(): string
+    {
+        return $this->path;
+    }
+}

tests/DataTest.php

@@ -143,9 +143,9 @@ public function testRemove()
         $data->remove('d.e.f');
         $data->remove('empty.path');
 
-        $this->assertNull($data->get('a'));
-        $this->assertNull($data->get('b/c'));
-        $this->assertNull($data->get('b.d.d3'));
+        $this->assertNull($data->get('a', null));
+        $this->assertNull($data->get('b/c', null));
+        $this->assertNull($data->get('b.d.d3', null));
         $this->assertNull(null);
         $this->assertEquals('D2', $data->get('b.d.d2'));
 
@@ -161,6 +161,21 @@ public function testGet()
         $this->runSampleDataTests($data);
     }
 
+    public function testGetWhenValueDoesNotExist()
+    {
+        $data = new Data($this->getSampleData());
+
+        // With a default parameter given:
+        $this->assertSame('DEFAULT', $data->get('foo.bar', 'DEFAULT'));
+        $this->assertSame(false, $data->get('foo.bar', false));
+        $this->assertSame(null, $data->get('foo/bar', null));
+
+        // Without a default parameter:
+        $this->expectException(DataException::class);
+        $this->expectExceptionMessage('No data exists at the given path: "foo » bar"');
+        $data->get('foo.bar');
+    }
+
     public function testHas()
     {
         $data = new Data($this->getSampleData());