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Infer ::from() and ::tryFrom() return types on backed enums
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Fixes #6429
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@weirdan
weirdan committed Nov 28, 2021
1 parent 2df5f22 commit 76bee7d
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Showing 5 changed files with 185 additions and 16 deletions.
11 changes: 9 additions & 2 deletions src/Psalm/Internal/Analyzer/ClassAnalyzer.php
View file
Expand Up @@ -2354,8 +2354,15 @@ private function checkImplementedInterfaces(
);
}

if ($storage->is_enum && $interface_method_name_lc === 'cases') {
continue;
if ($storage->is_enum) {
if ($interface_method_name_lc === 'cases') {
continue;
}
if ($storage->enum_type
&& in_array($interface_method_name_lc, ['from', 'tryfrom'], true)
) {
continue;
}
}

if (!$implementer_method_storage) {
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66 changes: 54 additions & 12 deletions src/Psalm/Internal/Codebase/Methods.php
View file
Expand Up @@ -121,8 +121,16 @@ public function methodExists(
return false;
}

if ($class_storage->is_enum && $method_name === 'cases') {
return true;
if ($class_storage->is_enum) {
if ($method_name === 'cases') {
return true;
}

if ($class_storage->enum_type
&& \in_array($method_name, ['from', 'tryFrom'], true)
) {
return true;
}
}

$source_file_path = $source ? $source->getFilePath() : $source_file_path;
Expand Down Expand Up @@ -686,21 +694,55 @@ public function getMethodReturnType(
$appearing_fq_class_storage = $this->classlike_storage_provider->get($appearing_fq_class_name);

if ($appearing_fq_class_name === 'UnitEnum'
&& $original_method_name === 'cases'
&& $original_class_storage->is_enum
&& $original_class_storage->enum_cases
) {
$types = [];
if ($original_method_name === 'cases') {
if ($original_class_storage->enum_cases === []) {
return Type::getEmptyArray();
}
$types = [];

foreach ($original_class_storage->enum_cases as $case_name => $_) {
$types[] = new Type\Union([new Type\Atomic\TEnumCase($original_fq_class_name, $case_name)]);
}
foreach ($original_class_storage->enum_cases as $case_name => $_) {
$types[] = new Type\Union([new Type\Atomic\TEnumCase($original_fq_class_name, $case_name)]);
}

$list = new Type\Atomic\TKeyedArray($types);
$list->is_list = true;
$list->sealed = true;
$list = new Type\Atomic\TKeyedArray($types);
$list->is_list = true;
$list->sealed = true;
return new Type\Union([$list]);
}
}

return new Type\Union([$list]);
if ($appearing_fq_class_name === 'BackedEnum'
&& $original_class_storage->is_enum
&& $original_class_storage->enum_type
) {
if (($original_method_name === 'from'
|| $original_method_name === 'tryfrom'
) && $source_analyzer
&& isset($args[0])
&& ($first_arg_type = $source_analyzer->getNodeTypeProvider()->getType($args[0]->value))
) {
$types = [];
foreach ($original_class_storage->enum_cases as $case_name => $case_storage) {
if (UnionTypeComparator::isContainedBy(
$source_analyzer->getCodebase(),
\is_int($case_storage->value) ?
Type::getInt(false, $case_storage->value) :
Type::getString($case_storage->value),
$first_arg_type,
)) {
$types[] = new Type\Atomic\TEnumCase($original_fq_class_name, $case_name);
}
}
if ($types) {
if ($original_method_name === 'tryfrom') {
$types[] = new Type\Atomic\TNull();
}
return new Type\Union($types);
}
return $original_method_name === 'tryfrom' ? Type::getNull() : Type::getNever();
}
}

if (!$appearing_fq_class_storage->user_defined
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12 changes: 11 additions & 1 deletion src/Psalm/Internal/PhpVisitor/Reflector/ClassLikeNodeScanner.php
View file
Expand Up @@ -300,7 +300,17 @@ public function start(PhpParser\Node\Stmt\ClassLike $node): ?bool
$this->file_storage->has_visitor_issues = true;
$storage->has_visitor_issues = true;
}
// todo: $this->codebase->scanner->queueClassLikeForScanning('BackedEnum');
$storage->class_implements['backedenum'] = 'BackedEnum';
$storage->direct_class_interfaces['backedenum'] = 'BackedEnum';
$this->file_storage->required_interfaces['backedenum'] = 'BackedEnum';
$this->codebase->scanner->queueClassLikeForScanning('BackedEnum');
$storage->declaring_method_ids['from'] = new \Psalm\Internal\MethodIdentifier('BackedEnum', 'from');
$storage->appearing_method_ids['from'] = $storage->declaring_method_ids['from'];
$storage->declaring_method_ids['tryfrom'] = new \Psalm\Internal\MethodIdentifier(
'BackedEnum',
'tryfrom'
);
$storage->appearing_method_ids['tryfrom'] = $storage->declaring_method_ids['tryfrom'];
}

$this->codebase->scanner->queueClassLikeForScanning('UnitEnum');
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9 changes: 8 additions & 1 deletion stubs/Php81.phpstub
View file
Expand Up @@ -3,10 +3,17 @@ namespace {
interface UnitEnum {
/** @var non-empty-string $name */
public readonly string $name;

/** @return non-empty-list<static> */
public static function cases(): array;
}

interface BackedEnum
{
public readonly int|string $value;
public static function from(string|int $value): static;
public static function tryFrom(string|int $value): ?static;
}
}

namespace FTP {
Expand Down
103 changes: 103 additions & 0 deletions tests/EnumTest.php
View file
Expand Up @@ -261,6 +261,109 @@ enum ParamType {
[],
'8.1',
],
'casesOnEnumWithNoCasesReturnEmptyArray' => [
'<?php
enum Status: int {}
$_z = Status::cases();
',
'assertions' => [
'$_z===' => 'array<empty, empty>',
],
[],
'8.1',
],
'backedEnumFromReturnsInstanceOfThatEnum' => [
'<?php
enum Status: int {
case Open = 1;
case Closed = 2;
}
function f(): Status {
return Status::from(1);
}
',
'assertions' => [],
[],
'8.1',
],
'backedEnumTryFromReturnsInstanceOfThatEnum' => [
'<?php
enum Status: int {
case Open = 1;
case Closed = 2;
}
function f(): Status {
return Status::tryFrom(rand(1, 10)) ?? Status::Open;
}
',
'assertions' => [],
[],
'8.1',
],
'backedEnumFromReturnsSpecificCase' => [
'<?php
enum Status: int {
case Open = 1;
case Closed = 2;
}
$_z = Status::from(2);
',
'assertions' => [
'$_z===' => 'enum(Status::Closed)',
],
[],
'8.1',
],
'backedEnumTryFromReturnsSpecificCase' => [
'<?php
enum Status: int {
case Open = 1;
case Closed = 2;
}
$_z = Status::tryFrom(2);
',
'assertions' => [
'$_z===' => 'enum(Status::Closed)|null',
],
[],
'8.1',
],
'backedEnumFromReturnsUnionOfCases' => [
'<?php
enum Status: int {
case Open = 1;
case Closed = 2;
case Busted = 3;
}
$_z = Status::from(rand(1, 2));
',
'assertions' => [
'$_z===' => 'enum(Status::Closed)|enum(Status::Open)',
],
[],
'8.1',
],
'backedEnumTryFromReturnsUnionOfCases' => [
'<?php
enum Status: int {
case Open = 1;
case Closed = 2;
case Busted = 3;
}
$_z = Status::tryFrom(rand(1, 2));
',
'assertions' => [
'$_z===' => 'enum(Status::Closed)|enum(Status::Open)|null',
],
[],
'8.1',
],
];
}

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