From 428acd7e190e2427a8ee8dce724afc79b0ea249f Mon Sep 17 00:00:00 2001
From: Grzegorz Rajchman <grzegorz.rajchman@technologyfromsage.com>
Date: Tue, 5 Dec 2023 12:51:35 +0000
Subject: [PATCH] PLT-71 Fix Undefined array key in remove triple (#145)

---
 src/classes/ExtendedGraph.class.php | 18 +++++++--
 test/unit/ExtendedGraphTest.php     | 62 +++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+), 4 deletions(-)

diff --git a/src/classes/ExtendedGraph.class.php b/src/classes/ExtendedGraph.class.php
index 69f0d17..fbb41d1 100644
--- a/src/classes/ExtendedGraph.class.php
+++ b/src/classes/ExtendedGraph.class.php
@@ -467,7 +467,7 @@ public function get_first_literal($s, $p, $default = null, $preferred_language =
      * @return string the first resource value found or the supplied default if no values were found
      */
     public function get_first_resource($s, $p, $default = null) {
-        if ( array_key_exists($s, $this->_index) && array_key_exists($p, $this->_index[$s]) ) {
+        if (isset($this->_index[$s][$p])) {
             foreach ($this->_index[$s][$p] as $value) {
                 if ($value['type'] == 'uri' || $value['type'] == 'bnode' ) {
                     return $value['value'];
@@ -483,7 +483,12 @@ public function get_first_resource($s, $p, $default = null) {
      * @param string $p the predicate URI of the triple
      * @param string $o the object of the triple, either a URI or a blank node in the format _:name
      */
-    public function remove_resource_triple( $s, $p, $o) {
+    public function remove_resource_triple($s, $p, $o) {
+        // Already removed
+        if (!isset($this->_index[$s]) || !isset($this->_index[$s][$p])) {
+            return;
+        }
+
         for ($i = count($this->_index[$s][$p]) - 1; $i >= 0; $i--) {
             if (($this->_index[$s][$p][$i]['type'] == 'uri' || $this->_index[$s][$p][$i]['type'] == 'bnode') && $this->_index[$s][$p][$i]['value'] == $o)  {
                 array_splice($this->_index[$s][$p], $i, 1);
@@ -493,10 +498,10 @@ public function remove_resource_triple( $s, $p, $o) {
         if (count($this->_index[$s][$p]) == 0) {
             unset($this->_index[$s][$p]);
         }
+
         if (count($this->_index[$s]) == 0) {
             unset($this->_index[$s]);
         }
-
     }
 
     /**
@@ -505,6 +510,11 @@ public function remove_resource_triple( $s, $p, $o) {
      * @param string $o
      */
     public function remove_literal_triple($s, $p, $o) {
+        // Already removed
+        if (!isset($this->_index[$s]) || !isset($this->_index[$s][$p])) {
+            return;
+        }
+
         for ($i = count($this->_index[$s][$p]) - 1; $i >= 0; $i--) {
             if ($this->_index[$s][$p][$i]['type'] == 'literal' && $this->_index[$s][$p][$i]['value'] == $o)  {
                 array_splice($this->_index[$s][$p], $i, 1);
@@ -514,10 +524,10 @@ public function remove_literal_triple($s, $p, $o) {
         if (count($this->_index[$s][$p]) == 0) {
             unset($this->_index[$s][$p]);
         }
+
         if (count($this->_index[$s]) == 0) {
             unset($this->_index[$s]);
         }
-
     }
 
     /**
diff --git a/test/unit/ExtendedGraphTest.php b/test/unit/ExtendedGraphTest.php
index 742ee56..f22f875 100644
--- a/test/unit/ExtendedGraphTest.php
+++ b/test/unit/ExtendedGraphTest.php
@@ -208,6 +208,68 @@ public function testRemoveProperties()
         $this->assertFalse($graph->subject_has_property('http://some/subject/3','http://some/predicate/to/remove'), 'should have removed triple about subject 3');
     }
 
+    public function testGetFirstResource()
+    {
+        $graph = new ExtendedGraph();
+
+        $graph->add_literal_triple('http://some/subject/1', 'http://some/predicate', 'value 1');
+        $graph->add_resource_triple('http://some/subject/1', 'http://some/predicate', 'http://value/2');
+
+        $this->assertEquals('http://value/2', $graph->get_first_resource('http://some/subject/1', 'http://some/predicate'), 'should have returned first resource');
+        $this->assertEquals(null, $graph->get_first_resource('http://some/subject/2', 'http://other/predicate'), 'should have returned default value');
+        $this->assertEquals('my default', $graph->get_first_resource('http://some/subject/3', 'http://other/predicate', 'my default'), 'should have returned default value');
+    }
+
+    public function testRemoveResourceTriple()
+    {
+        $graph = new ExtendedGraph();
+
+        // Add some triples
+        $graph->add_resource_triple('http://some/subject/1', 'http://some/predicate', 'http://value/1');
+        $graph->add_resource_triple('http://some/subject/2', 'http://some/predicate', 'http://value/2');
+        $this->assertEquals(2, $graph->get_triple_count(), 'should have 2 triples');
+
+        // Try to remove triples that don't exist
+        $graph->remove_resource_triple('http://some/subject/3', 'http://some/predicate', 'http://value/3');
+        $graph->remove_literal_triple('http://some/subject/3', 'http://some/predicate', 'value 3');
+        $this->assertEquals(2, $graph->get_triple_count(), 'should have 2 triples');
+
+        // Remove a triple that does exist
+        $graph->remove_resource_triple('http://some/subject/1', 'http://some/predicate', 'http://value/1');
+        $this->assertEquals(1, $graph->get_triple_count(), 'should have 1 triple');
+
+        // Remove the last triple
+        $graph->remove_resource_triple('http://some/subject/2', 'http://some/predicate', 'http://value/2');
+        $this->assertEquals(0, $graph->get_triple_count(), 'should have 0 triples');
+        $this->assertTrue($graph->is_empty(), 'should be empty');
+        $this->assertEquals([], $graph->get_index(), 'should have empty index');
+    }
+
+    public function testRemoveLiteralTriple()
+    {
+        $graph = new ExtendedGraph();
+
+        // Add some triples
+        $graph->add_literal_triple('http://some/subject/1', 'http://some/predicate', 'value 1');
+        $graph->add_literal_triple('http://some/subject/2', 'http://some/predicate', 'value 2');
+        $this->assertEquals(2, $graph->get_triple_count(), 'should have 2 triples');
+
+        // Try to remove triples that don't exist
+        $graph->remove_literal_triple('http://some/subject/3', 'http://some/predicate', 'value 3');
+        $graph->remove_resource_triple('http://some/subject/3', 'http://some/predicate', 'http://value/3');
+        $this->assertEquals(2, $graph->get_triple_count(), 'should have 2 triples');
+
+        // Remove a triple that does exist
+        $graph->remove_literal_triple('http://some/subject/1', 'http://some/predicate', 'value 1');
+        $this->assertEquals(1, $graph->get_triple_count(), 'should have 1 triple');
+
+        // Remove the last triple
+        $graph->remove_literal_triple('http://some/subject/2', 'http://some/predicate', 'value 2');
+        $this->assertEquals(0, $graph->get_triple_count(), 'should have 0 triples');
+        $this->assertTrue($graph->is_empty(), 'should be empty');
+        $this->assertEquals([], $graph->get_index(), 'should have empty index');
+    }
+
     public function testGetResourceProperties()
     {
         $graph = new ExtendedGraph();