Track references on global variables (#5122)

* Track references on global variables

Add global type references to the type map, and fix up unused detection on global variables.

* Add null assertions

* PHPCS

src/Psalm/Codebase.php

@@ -21,6 +21,7 @@ use Psalm\Internal\Analyzer\ProjectAnalyzer;
 use Psalm\Internal\Analyzer\NamespaceAnalyzer;
 use Psalm\Internal\Analyzer\Statements\Block\ForeachAnalyzer;
 use Psalm\Internal\Analyzer\Statements\Expression\Fetch\ConstFetchAnalyzer;
+use Psalm\Internal\Analyzer\Statements\Expression\Fetch\VariableFetchAnalyzer;
 use Psalm\Internal\Type\Comparator\UnionTypeComparator;
 use Psalm\Internal\Codebase\InternalCallMapHandler;
 use Psalm\Internal\Provider\ClassLikeStorageProvider;
@@ -1004,6 +1005,13 @@ class Codebase
                 return '<?php ' . $function->getSignature(true);
             }
 
+            if (strpos($symbol, '$') === 0) {
+                $type = VariableFetchAnalyzer::getGlobalType($symbol);
+                if (!$type->isMixed()) {
+                    return '<?php ' . $type;
+                }
+            }
+
             try {
                 $storage = $this->classlike_storage_provider->get($symbol);
                 return '<?php ' . ($storage->abstract ? 'abstract ' : '') . 'class ' . $storage->name;

src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/VariableFetchAnalyzer.php

@@ -165,6 +165,12 @@ class VariableFetchAnalyzer
             $context->vars_in_scope[$var_name] = clone $type;
             $context->vars_possibly_in_scope[$var_name] = true;
 
+            $codebase->analyzer->addNodeReference(
+                $statements_analyzer->getFilePath(),
+                $stmt,
+                $var_name
+            );
+
             return true;
         }
 

src/Psalm/Internal/Analyzer/Statements/GlobalAnalyzer.php

@@ -5,6 +5,7 @@ use PhpParser;
 use Psalm\Internal\Analyzer\FunctionLikeAnalyzer;
 use Psalm\Internal\Analyzer\StatementsAnalyzer;
 use Psalm\Internal\Analyzer\Statements\Expression\Fetch\VariableFetchAnalyzer;
+use Psalm\Internal\DataFlow\DataFlowNode;
 use Psalm\CodeLocation;
 use Psalm\Context;
 use Psalm\Issue\InvalidGlobal;
@@ -56,6 +57,23 @@ class GlobalAnalyzer
 
                         $context->byref_constraints[$var_id] = new \Psalm\Internal\ReferenceConstraint();
                     }
+                    $assignment_node = DataFlowNode::getForAssignment(
+                        $var_id,
+                        new CodeLocation($statements_analyzer, $var)
+                    );
+                    $context->vars_in_scope[$var_id]->parent_nodes = [
+                        $assignment_node->id => $assignment_node,
+                    ];
+                    $statements_analyzer->registerVariable(
+                        $var_id,
+                        new CodeLocation($statements_analyzer, $var),
+                        $context->branch_point
+                    );
+                    $statements_analyzer->getCodebase()->analyzer->addNodeReference(
+                        $statements_analyzer->getFilePath(),
+                        $var,
+                        $var_id
+                    );
                 }
             }
         }

tests/LanguageServer/SymbolLookupTest.php

@@ -39,6 +39,9 @@ class SymbolLookupTest extends \Psalm\Tests\TestCase
 
     public function testSimpleSymbolLookup(): void
     {
+        $codebase = $this->project_analyzer->getCodebase();
+        $config = $codebase->config;
+        $config->globals['$my_global'] = 'string';
         $this->addFile(
             'somefile.php',
             '<?php
@@ -68,7 +71,9 @@ class SymbolLookupTest extends \Psalm\Tests\TestCase
 
                 function qux(int $a, int $b) : int {
                     return $a + $b;
-                }'
+                }
+
+                $_SERVER;'
         );
 
         new FileAnalyzer($this->project_analyzer, 'somefile.php', 'somefile.php');
@@ -83,7 +88,8 @@ class SymbolLookupTest extends \Psalm\Tests\TestCase
         $this->assertSame('<?php BANANA', $codebase->getSymbolInformation('somefile.php', 'B\A::BANANA'));
         $this->assertSame("<?php function B\baz(\n    int \$a\n) : int", $codebase->getSymbolInformation('somefile.php', 'B\baz()'));
         $this->assertSame("<?php function B\qux(\n    int \$a,\n    int \$b\n) : int", $codebase->getSymbolInformation('somefile.php', 'B\qux()'));
-        $this->assertSame("<?php const B\APPLE string", $codebase->getSymbolInformation('somefile.php', 'B\APPLE'));
+        $this->assertSame("<?php array<array-key, mixed>", $codebase->getSymbolInformation('somefile.php', '$_SERVER'));
+        $this->assertSame("<?php string", $codebase->getSymbolInformation('somefile.php', '$my_global'));
     }
 
     public function testSimpleSymbolLookupGlobalConst(): void
@@ -279,6 +285,36 @@ class SymbolLookupTest extends \Psalm\Tests\TestCase
         $this->assertSame('B\A::foo()', $symbol_at_position[0]);
     }
 
+    public function testGetSymbolPositionGlobalVariable(): void
+    {
+        $codebase = $this->project_analyzer->getCodebase();
+        $codebase->reportUnusedVariables();
+        $config = $codebase->config;
+        $config->throw_exception = false;
+        $config->globals['$my_global'] = 'string';
+
+        $this->addFile(
+            'somefile.php',
+            '<?php
+                function foo() : void {
+                    global $my_global;
+                    echo $my_global;
+                }'
+        );
+
+        $codebase->file_provider->openFile('somefile.php');
+        $codebase->scanFiles();
+        $this->analyzeFile('somefile.php', new Context());
+
+        $symbol_at_position = $codebase->getReferenceAtPosition('somefile.php', new Position(2, 31));
+        $this->assertNotNull($symbol_at_position);
+        $this->assertSame('$my_global', $symbol_at_position[0]);
+
+        $symbol_at_position = $codebase->getReferenceAtPosition('somefile.php', new Position(3, 28));
+        $this->assertNotNull($symbol_at_position);
+        $this->assertSame('73-82:string', $symbol_at_position[0]);
+    }
+
     public function testGetSymbolPositionNullableArg(): void
     {
         $codebase = $this->project_analyzer->getCodebase();

tests/UnusedVariableTest.php

@@ -3114,6 +3114,15 @@ class UnusedVariableTest extends TestCase
                     };',
                 'error_message' => 'UnusedVariable',
             ],
+            'globalVariableUsage' => [
+                '<?php
+                    $a = "hello";
+                    function example() : void {
+                        global $a;
+                    }
+                    example();',
+                'error_message' => 'UnusedVariable',
+            ],
         ];
     }
 }