From 5f019cef537087d69bfda9a318f4e9a092f0391b Mon Sep 17 00:00:00 2001
From: Niclas van Eyk <NiclasvanEyk@users.noreply.github.com>
Date: Mon, 19 Oct 2020 21:08:18 +0200
Subject: [PATCH] Initial proposal for psalm-require-{extends, implements}
 (#4361)

* initial implementation of psalm-require-extends

* Added @psalm-require-implements

* Added shortcode for ExtensionRequirementViolation

* Docs & cofig entries for @pasalm-require-{implements,extends}

* Added requirement violations to issues.md
---
 config.xsd                                    |  2 +
 docs/running_psalm/issues.md                  |  2 +
 .../issues/ExtensionRequirementViolation.md   | 20 +++++
 .../ImplementationRequirementViolation.md     | 22 +++++
 src/Psalm/DocComment.php                      |  4 +-
 src/Psalm/Internal/Analyzer/ClassAnalyzer.php | 41 +++++++++
 .../Internal/Analyzer/CommentAnalyzer.php     | 21 ++++-
 .../Internal/PhpVisitor/ReflectorVisitor.php  | 28 +++++++
 .../Scanner/ClassLikeDocblockComment.php      | 10 +++
 .../Issue/ExtensionRequirementViolation.php   |  9 ++
 .../ImplementationRequirementViolation.php    |  9 ++
 src/Psalm/Storage/ClassLikeStorage.php        | 10 +++
 tests/ExtensionRequirementTest.php            | 67 +++++++++++++++
 tests/ImplementationRequirementTest.php       | 84 +++++++++++++++++++
 14 files changed, 327 insertions(+), 2 deletions(-)
 create mode 100644 docs/running_psalm/issues/ExtensionRequirementViolation.md
 create mode 100644 docs/running_psalm/issues/ImplementationRequirementViolation.md
 create mode 100644 src/Psalm/Issue/ExtensionRequirementViolation.php
 create mode 100644 src/Psalm/Issue/ImplementationRequirementViolation.php
 create mode 100644 tests/ExtensionRequirementTest.php
 create mode 100644 tests/ImplementationRequirementTest.php

diff --git a/config.xsd b/config.xsd
index 8d54e0ab8..72416f403 100644
--- a/config.xsd
+++ b/config.xsd
@@ -197,11 +197,13 @@
             <xs:element name="DuplicateMethod" type="MethodIssueHandlerType" minOccurs="0" />
             <xs:element name="DuplicateParam" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="EmptyArrayAccess" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="ExtensionRequirementViolation" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="FalsableReturnStatement" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="FalseOperand" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="ForbiddenCode" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="ForbiddenEcho" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="IfThisIsMismatch" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="ImplementationRequirementViolation" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="ImplementedParamTypeMismatch" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="ImplementedReturnTypeMismatch" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="ImplicitToStringCast" type="IssueHandlerType" minOccurs="0" />
diff --git a/docs/running_psalm/issues.md b/docs/running_psalm/issues.md
index 2e1233eda..3b65c49a3 100644
--- a/docs/running_psalm/issues.md
+++ b/docs/running_psalm/issues.md
@@ -21,11 +21,13 @@
  - [DuplicateMethod](issues/DuplicateMethod.md)
  - [DuplicateParam](issues/DuplicateParam.md)
  - [EmptyArrayAccess](issues/EmptyArrayAccess.md)
+ - [ExtensionRequirementViolation](issues/ExtensionRequirementViolation.md)
  - [FalsableReturnStatement](issues/FalsableReturnStatement.md)
  - [FalseOperand](issues/FalseOperand.md)
  - [ForbiddenCode](issues/ForbiddenCode.md)
  - [ForbiddenEcho](issues/ForbiddenEcho.md)
  - [IfThisIsMismatch](issues/IfThisIsMismatch.md)
+ - [ImplementationRequirementViolation](issues/ImplementationRequirementViolation.md)
  - [ImplementedParamTypeMismatch](issues/ImplementedParamTypeMismatch.md)
  - [ImplementedReturnTypeMismatch](issues/ImplementedReturnTypeMismatch.md)
  - [ImplicitToStringCast](issues/ImplicitToStringCast.md)
diff --git a/docs/running_psalm/issues/ExtensionRequirementViolation.md b/docs/running_psalm/issues/ExtensionRequirementViolation.md
new file mode 100644
index 000000000..0c540e1b9
--- /dev/null
+++ b/docs/running_psalm/issues/ExtensionRequirementViolation.md
@@ -0,0 +1,20 @@
+# ExtensionRequirementViolation
+
+Emitted when a using class of a trait does not extend the class specified using `@psalm-require-extends`.
+
+```php
+<?php
+
+class A { }
+
+/**
+ * @psalm-require-extends A
+ */
+trait T { }
+
+class B {
+  // ExtensionRequirementViolation is emitted, as T requires
+  // the using class B to extend A, which is not the case
+  use T; 
+}
+```
diff --git a/docs/running_psalm/issues/ImplementationRequirementViolation.md b/docs/running_psalm/issues/ImplementationRequirementViolation.md
new file mode 100644
index 000000000..eb57e1675
--- /dev/null
+++ b/docs/running_psalm/issues/ImplementationRequirementViolation.md
@@ -0,0 +1,22 @@
+# ImplementationRequirementViolation
+
+Emitted when a using class of a trait does not implement all interfaces specified using `@psalm-require-implements`.
+
+```php
+<?php
+
+interface A { }
+interface B { }
+
+/**
+ * @psalm-require-implements A
+ * @psalm-require-implements B
+ */
+trait T { }
+
+class C {
+  // ImplementationRequirementViolation is emitted, as T requires
+  // the using class C to implement A and B, which is not the case
+  use T; 
+}
+```
diff --git a/src/Psalm/DocComment.php b/src/Psalm/DocComment.php
index 153c390dd..b07e1782e 100644
--- a/src/Psalm/DocComment.php
+++ b/src/Psalm/DocComment.php
@@ -34,7 +34,9 @@ class DocComment
         'mutation-free', 'external-mutation-free', 'immutable', 'readonly',
         'allow-private-mutation', 'readonly-allow-private-mutation',
         'yield', 'trace', 'import-type', 'flow', 'taint-specialize', 'taint-escape',
-        'taint-unescape', 'self-out', 'if-this-is', 'consistent-constructor', 'stub-override'
+        'taint-unescape', 'self-out', 'consistent-constructor', 'stub-override',
+        'require-extends', 'require-implements',
+        'if-this-is'
     ];
 
     /**
diff --git a/src/Psalm/Internal/Analyzer/ClassAnalyzer.php b/src/Psalm/Internal/Analyzer/ClassAnalyzer.php
index 52f1e94b4..fdbc8a79e 100644
--- a/src/Psalm/Internal/Analyzer/ClassAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/ClassAnalyzer.php
@@ -16,6 +16,8 @@ use Psalm\Context;
 use Psalm\Issue\DeprecatedClass;
 use Psalm\Issue\DeprecatedInterface;
 use Psalm\Issue\DeprecatedTrait;
+use Psalm\Issue\ExtensionRequirementViolation;
+use Psalm\Issue\ImplementationRequirementViolation;
 use Psalm\Issue\InaccessibleMethod;
 use Psalm\Issue\InternalClass;
 use Psalm\Issue\InvalidExtendClass;
@@ -54,6 +56,7 @@ use function array_search;
 use function array_keys;
 use function array_merge;
 use function array_filter;
+use function in_array;
 
 /**
  * @internal
@@ -1540,6 +1543,44 @@ class ClassAnalyzer extends ClassLikeAnalyzer
                     }
                 }
 
+                if ($trait_storage->extension_requirement !== null) {
+                    $extension_requirement = $codebase->classlikes->getUnAliasedName(
+                        $trait_storage->extension_requirement
+                    );
+                    $extensionRequirementMet = in_array($extension_requirement, $storage->parent_classes);
+
+                    if (!$extensionRequirementMet) {
+                        if (IssueBuffer::accepts(
+                            new ExtensionRequirementViolation(
+                                $fq_trait_name . ' requires using class to extend ' . $extension_requirement
+                                    . ', but ' . $storage->name . ' does not',
+                                new CodeLocation($previous_trait_analyzer ?: $this, $trait_name)
+                            ),
+                            $storage->suppressed_issues + $this->getSuppressedIssues()
+                        )) {
+                            // fall through
+                        }
+                    }
+                }
+
+                foreach ($trait_storage->implementation_requirements as $implementation_requirement) {
+                    $implementation_requirement = $codebase->classlikes->getUnAliasedName($implementation_requirement);
+                    $implementationRequirementMet = in_array($implementation_requirement, $storage->class_implements);
+
+                    if (!$implementationRequirementMet) {
+                        if (IssueBuffer::accepts(
+                            new ImplementationRequirementViolation(
+                                $fq_trait_name . ' requires using class to implement '
+                                    . $implementation_requirement . ', but ' . $storage->name . ' does not',
+                                new CodeLocation($previous_trait_analyzer ?: $this, $trait_name)
+                            ),
+                            $storage->suppressed_issues + $this->getSuppressedIssues()
+                        )) {
+                            // fall through
+                        }
+                    }
+                }
+
                 if ($storage->mutation_free && !$trait_storage->mutation_free) {
                     if (IssueBuffer::accepts(
                         new MutableDependency(
diff --git a/src/Psalm/Internal/Analyzer/CommentAnalyzer.php b/src/Psalm/Internal/Analyzer/CommentAnalyzer.php
index 7c9dc60fd..c627a48a4 100644
--- a/src/Psalm/Internal/Analyzer/CommentAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/CommentAnalyzer.php
@@ -17,7 +17,6 @@ use Psalm\Internal\Type\ParseTreeCreator;
 use Psalm\Internal\Type\TypeAlias;
 use Psalm\Internal\Type\TypeParser;
 use Psalm\Internal\Type\TypeTokenizer;
-use Psalm\Type;
 use function array_unique;
 use function trim;
 use function substr_count;
@@ -40,6 +39,7 @@ use function explode;
 use function array_merge;
 use const PREG_OFFSET_CAPTURE;
 use function rtrim;
+use function array_key_first;
 
 /**
  * @internal
@@ -889,6 +889,25 @@ class CommentAnalyzer
             }
         }
 
+        if (isset($parsed_docblock->tags['psalm-require-extends'])
+            && count($extension_requirements = $parsed_docblock->tags['psalm-require-extends']) > 0) {
+            $info->extension_requirement = trim(preg_replace(
+                '@^[ \t]*\*@m',
+                '',
+                $extension_requirements[array_key_first($extension_requirements)]
+            ));
+        }
+
+        if (isset($parsed_docblock->tags['psalm-require-implements'])) {
+            foreach ($parsed_docblock->tags['psalm-require-implements'] as $implementation_requirement) {
+                $info->implementation_requirements[] = trim(preg_replace(
+                    '@^[ \t]*\*@m',
+                    '',
+                    $implementation_requirement
+                ));
+            }
+        }
+
         if (isset($parsed_docblock->combined_tags['implements'])) {
             foreach ($parsed_docblock->combined_tags['implements'] as $template_line) {
                 $info->template_implements[] = trim(preg_replace('@^[ \t]*\*@m', '', $template_line));
diff --git a/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php b/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php
index baf6b81f2..e94fcb3f3 100644
--- a/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php
+++ b/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php
@@ -1277,6 +1277,34 @@ class ReflectorVisitor extends PhpParser\NodeVisitorAbstract implements FileSour
                     }
                 }
 
+                if ($docblock_info->extension_requirement !== null) {
+                    $storage->extension_requirement = (string) TypeParser::parseTokens(
+                        TypeTokenizer::getFullyQualifiedTokens(
+                            $docblock_info->extension_requirement,
+                            $this->aliases,
+                            $this->class_template_types,
+                            $this->type_aliases
+                        ),
+                        null,
+                        $this->class_template_types,
+                        $this->type_aliases
+                    );
+                }
+
+                foreach ($docblock_info->implementation_requirements as $implementation_requirement) {
+                    $storage->implementation_requirements[] = (string) TypeParser::parseTokens(
+                        TypeTokenizer::getFullyQualifiedTokens(
+                            $implementation_requirement,
+                            $this->aliases,
+                            $this->class_template_types,
+                            $this->type_aliases
+                        ),
+                        null,
+                        $this->class_template_types,
+                        $this->type_aliases
+                    );
+                }
+
                 $storage->sealed_properties = $docblock_info->sealed_properties;
                 $storage->sealed_methods = $docblock_info->sealed_methods;
 
diff --git a/src/Psalm/Internal/Scanner/ClassLikeDocblockComment.php b/src/Psalm/Internal/Scanner/ClassLikeDocblockComment.php
index e8c945052..0df5cd943 100644
--- a/src/Psalm/Internal/Scanner/ClassLikeDocblockComment.php
+++ b/src/Psalm/Internal/Scanner/ClassLikeDocblockComment.php
@@ -127,4 +127,14 @@ class ClassLikeDocblockComment
 
     /** @var bool */
     public $stub_override = false;
+
+    /**
+     * @var null|string
+     */
+    public $extension_requirement;
+
+    /**
+     * @var array<int, string>
+     */
+    public $implementation_requirements = [];
 }
diff --git a/src/Psalm/Issue/ExtensionRequirementViolation.php b/src/Psalm/Issue/ExtensionRequirementViolation.php
new file mode 100644
index 000000000..4fce9cdd4
--- /dev/null
+++ b/src/Psalm/Issue/ExtensionRequirementViolation.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace Psalm\Issue;
+
+class ExtensionRequirementViolation extends CodeIssue
+{
+    public const ERROR_LEVEL = -1;
+    public const SHORTCODE = 239;
+}
diff --git a/src/Psalm/Issue/ImplementationRequirementViolation.php b/src/Psalm/Issue/ImplementationRequirementViolation.php
new file mode 100644
index 000000000..1b6886f02
--- /dev/null
+++ b/src/Psalm/Issue/ImplementationRequirementViolation.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace Psalm\Issue;
+
+class ImplementationRequirementViolation extends CodeIssue
+{
+    public const ERROR_LEVEL = -1;
+    public const SHORTCODE = 240;
+}
diff --git a/src/Psalm/Storage/ClassLikeStorage.php b/src/Psalm/Storage/ClassLikeStorage.php
index 2c72fd375..fb8802bbf 100644
--- a/src/Psalm/Storage/ClassLikeStorage.php
+++ b/src/Psalm/Storage/ClassLikeStorage.php
@@ -368,6 +368,16 @@ class ClassLikeStorage
      */
     public $preserve_constructor_signature = false;
 
+    /**
+     * @var null|string
+     */
+    public $extension_requirement;
+
+    /**
+     * @var array<int, string>
+     */
+    public $implementation_requirements = [];
+
     public function __construct(string $name)
     {
         $this->name = $name;
diff --git a/tests/ExtensionRequirementTest.php b/tests/ExtensionRequirementTest.php
new file mode 100644
index 000000000..235164a27
--- /dev/null
+++ b/tests/ExtensionRequirementTest.php
@@ -0,0 +1,67 @@
+<?php
+
+namespace Psalm\Tests;
+
+class ExtensionRequirementTest extends TestCase
+{
+    use Traits\ValidCodeAnalysisTestTrait;
+    use Traits\InvalidCodeAnalysisTestTrait;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->addFile(
+            'base.php',
+            '<?php
+                namespace ExtensionRequirements\Base;
+
+                class MyBaseClass { }
+            '
+        );
+
+        $this->addFile(
+            'trait.php',
+            '<?php
+                namespace ExtensionRequirements\Trait;
+
+                use ExtensionRequirements\Base\MyBaseClass as MyAliasedBaseClass;
+
+                /** @psalm-require-extends MyAliasedBaseClass */
+                trait ImposesExtensionRequirements { }
+            '
+        );
+    }
+
+    public function providerValidCodeParse(): iterable
+    {
+        return [
+            'extendsBaseClass' => [
+                '<?php
+                    use ExtensionRequirements\Base\MyBaseClass;
+                    use ExtensionRequirements\Trait\ImposesExtensionRequirements;
+
+                    class Valid extends MyBaseClass {
+                        use ImposesExtensionRequirements;
+                    }
+                '
+            ]
+        ];
+    }
+
+    public function providerInvalidCodeParse(): iterable
+    {
+        return [
+            'extendsBaseClass' => [
+                '<?php
+                    use ExtensionRequirements\Trait\ImposesExtensionRequirements;
+
+                    class Invalid {
+                        use ImposesExtensionRequirements;
+                    }
+                ',
+                'error_message' => 'requires using class to extend'
+            ]
+        ];
+    }
+}
diff --git a/tests/ImplementationRequirementTest.php b/tests/ImplementationRequirementTest.php
new file mode 100644
index 000000000..2984e8a9f
--- /dev/null
+++ b/tests/ImplementationRequirementTest.php
@@ -0,0 +1,84 @@
+<?php
+
+namespace Psalm\Tests;
+
+class ImplementationRequirementTest extends TestCase
+{
+    use Traits\ValidCodeAnalysisTestTrait;
+    use Traits\InvalidCodeAnalysisTestTrait;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->addFile(
+            'base.php',
+            '<?php
+                namespace ImplementationRequirements\Base;
+
+                interface A { }
+                interface B { }
+            '
+        );
+
+        $this->addFile(
+            'trait.php',
+            '<?php
+                namespace ImplementationRequirements\Trait;
+
+                use ImplementationRequirements\Base\A as MyAliasedInterfaceA;
+                use ImplementationRequirements\Base\B as MyAliasedInterfaceB;
+
+                /**
+                 * @psalm-require-implements MyAliasedInterfaceA
+                 * @psalm-require-implements MyAliasedInterfaceB
+                 */
+                trait ImposesImplementationRequirements { }
+            '
+        );
+    }
+
+    public function providerValidCodeParse(): iterable
+    {
+        return [
+            'implementsAllRequirements' => [
+                '<?php
+                    use ImplementationRequirements\Base\A;
+                    use ImplementationRequirements\Base\B;
+                    use ImplementationRequirements\Trait\ImposesImplementationRequirements;
+
+                    class Valid implements A, B {
+                        use ImposesImplementationRequirements;
+                    }
+                '
+            ]
+        ];
+    }
+
+    public function providerInvalidCodeParse(): iterable
+    {
+        return [
+            'doesNotImplementAnything' => [
+                '<?php
+                    use ImplementationRequirements\Trait\ImposesImplementationRequirements;
+
+                    class Invalid {
+                        use ImposesImplementationRequirements;
+                    }
+                ',
+                'error_message' => 'requires using class to implement'
+            ],
+            'onlyImplementsOneRequirement' => [
+                '<?php
+                    use ImplementationRequirements\Trait\ImposesImplementationRequirements;
+                    use ImplementationRequirements\Base\A;
+
+                    class Invalid implements A {
+                        use ImposesImplementationRequirements;
+                    }
+                ',
+                'error_message' => 'requires using class to implement'
+            ]
+        ];
+    }
+}