Add NoDiscard attribute on mutation free methods and methods returning monads

psalm.xml

@@ -14,4 +14,7 @@
             <directory name="vendor" />
         </ignoreFiles>
     </projectFiles>
+    <issueHandlers>
+        <UndefinedAttributeClass errorLevel="suppress" />
+    </issueHandlers>
 </psalm>

src/Config.php

@@ -29,6 +29,8 @@
 final class Config
 {
     /**
+     * @psalm-mutation-free
+     *
      * @param \Closure(Clock, self): Clock $mapClock
      * @param \Closure(Halt, self): Halt $mapHalt
      * @param \Closure(HttpTransport, self): HttpTransport $mapHttpTransport
@@ -60,6 +62,7 @@ private function __construct(
     ) {
     }
 
+    #[\NoDiscard]
     public static function new(): self
     {
         return new self(
@@ -97,6 +100,7 @@ public static function new(): self
      *
      * @param callable(self): self $map
      */
+    #[\NoDiscard]
     public function map(callable $map): self
     {
         /** @psalm-suppress ImpureFunctionCall */
@@ -106,6 +110,7 @@ public function map(callable $map): self
     /**
      * @psalm-mutation-free
      */
+    #[\NoDiscard]
     public function withClock(Clock $clock): self
     {
         return new self(
@@ -133,6 +138,7 @@ public function withClock(Clock $clock): self
      *
      * @param \Closure(Clock, self): Clock $map
      */
+    #[\NoDiscard]
     public function mapClock(\Closure $map): self
     {
         $previous = $this->mapClock;
@@ -163,6 +169,7 @@ public function mapClock(\Closure $map): self
     /**
      * @psalm-mutation-free
      */
+    #[\NoDiscard]
     public function haltProcessVia(Halt $halt): self
     {
         return new self(
@@ -190,6 +197,7 @@ public function haltProcessVia(Halt $halt): self
      *
      * @param \Closure(Halt, self): Halt $map
      */
+    #[\NoDiscard]
     public function mapHalt(\Closure $map): self
     {
         $previous = $this->mapHalt;
@@ -221,6 +229,7 @@ public function mapHalt(\Closure $map): self
     /**
      * @psalm-mutation-free
      */
+    #[\NoDiscard]
     public function withIO(IO $io): self
     {
         return new self(
@@ -246,6 +255,7 @@ public function withIO(IO $io): self
     /**
      * @psalm-mutation-free
      */
+    #[\NoDiscard]
     public function withEnvironmentPath(EnvironmentPath $path): self
     {
         return new self(
@@ -271,6 +281,7 @@ public function withEnvironmentPath(EnvironmentPath $path): self
     /**
      * @psalm-mutation-free
      */
+    #[\NoDiscard]
     public function useHttpTransport(HttpTransport $transport): self
     {
         return new self(
@@ -298,6 +309,7 @@ public function useHttpTransport(HttpTransport $transport): self
      *
      * @param \Closure(HttpTransport, self): HttpTransport $map
      */
+    #[\NoDiscard]
     public function mapHttpTransport(\Closure $map): self
     {
         $previous = $this->mapHttpTransport;
@@ -330,6 +342,7 @@ public function mapHttpTransport(\Closure $map): self
      *
      * @param \Closure(Url): AccessLayer\Connection $sql
      */
+    #[\NoDiscard]
     public function openSQLConnectionVia(\Closure $sql): self
     {
         return new self(
@@ -357,6 +370,7 @@ public function openSQLConnectionVia(\Closure $sql): self
      *
      * @param \Closure(AccessLayer\Connection, self): AccessLayer\Connection $map
      */
+    #[\NoDiscard]
     public function mapSQLConnection(\Closure $map): self
     {
         $previous = $this->mapSql;
@@ -389,6 +403,7 @@ public function mapSQLConnection(\Closure $map): self
      *
      * @param \Closure(Control\Server, self): Control\Server $map
      */
+    #[\NoDiscard]
     public function mapServerControl(\Closure $map): self
     {
         $previous = $this->mapServerControl;
@@ -421,6 +436,7 @@ public function mapServerControl(\Closure $map): self
      *
      * @param \Closure(Status\Server, self): Status\Server $map
      */
+    #[\NoDiscard]
     public function mapServerStatus(\Closure $map): self
     {
         $previous = $this->mapServerStatus;
@@ -453,6 +469,7 @@ public function mapServerStatus(\Closure $map): self
      *
      * @param \Closure(Watch, self): Watch $map
      */
+    #[\NoDiscard]
     public function mapFileWatch(\Closure $map): self
     {
         $previous = $this->mapFileWatch;
@@ -485,6 +502,7 @@ public function mapFileWatch(\Closure $map): self
      *
      * @param \Closure(Path, self): Attempt<Filesystem> $filesystem
      */
+    #[\NoDiscard]
     public function mountFilesystemVia(\Closure $filesystem): self
     {
         return new self(
@@ -512,6 +530,7 @@ public function mountFilesystemVia(\Closure $filesystem): self
      *
      * @param \Closure(Filesystem, self): Filesystem $map
      */
+    #[\NoDiscard]
     public function mapFilesystem(\Closure $map): self
     {
         $previous = $this->mapFilesystem;
@@ -542,6 +561,7 @@ public function mapFilesystem(\Closure $map): self
     /**
      * @psalm-mutation-free
      */
+    #[\NoDiscard]
     public function handleSignalsVia(Handler $handler): self
     {
         return new self(
@@ -567,6 +587,7 @@ public function handleSignalsVia(Handler $handler): self
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function clock(): Clock
     {
         return ($this->mapClock)($this->clock, $this);
@@ -577,6 +598,7 @@ public function clock(): Clock
      *
      * @return Attempt<Filesystem>
      */
+    #[\NoDiscard]
     public function filesystem(Path $path): Attempt
     {
         return ($this->filesystem)($path, $this)->map(
@@ -587,6 +609,7 @@ public function filesystem(Path $path): Attempt
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function io(): IO
     {
         return $this->io;
@@ -595,6 +618,7 @@ public function io(): IO
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function halt(): Halt
     {
         return ($this->mapHalt)($this->halt, $this);
@@ -603,6 +627,7 @@ public function halt(): Halt
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function environmentPath(): EnvironmentPath
     {
         return $this->path;
@@ -611,6 +636,7 @@ public function environmentPath(): EnvironmentPath
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function httpTransport(): HttpTransport
     {
         $transport = $this->httpTransport ?? Curl::of(
@@ -624,6 +650,7 @@ public function httpTransport(): HttpTransport
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function sql(Url $url): AccessLayer\Connection
     {
         return ($this->mapSql)(
@@ -635,6 +662,7 @@ public function sql(Url $url): AccessLayer\Connection
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function serverControl(Control\Server $server): Control\Server
     {
         return ($this->mapServerControl)($server, $this);
@@ -643,6 +671,7 @@ public function serverControl(Control\Server $server): Control\Server
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function serverStatus(Status\Server $server): Status\Server
     {
         return ($this->mapServerStatus)($server, $this);
@@ -651,6 +680,7 @@ public function serverStatus(Status\Server $server): Status\Server
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function fileWatch(Watch $watch): Watch
     {
         return ($this->mapFileWatch)($watch, $this);
@@ -659,6 +689,7 @@ public function fileWatch(Watch $watch): Watch
     /**
      * @internal
      */
+    #[\NoDiscard]
     public function signalsHandler(): Handler
     {
         return $this->signals;

src/Config/Logger.php

@@ -14,13 +14,17 @@
 use Formal\AccessLayer\Connection;
 use Psr\Log\LoggerInterface;
 
+/**
+ * @psalm-immutable
+ */
 final class Logger
 {
     private function __construct(
         private LoggerInterface $logger,
     ) {
     }
 
+    #[\NoDiscard]
     public function __invoke(Config $config): Config
     {
         return $config
@@ -55,6 +59,10 @@ public function __invoke(Config $config): Config
             ));
     }
 
+    /**
+     * @psalm-pure
+     */
+    #[\NoDiscard]
     public static function psr(LoggerInterface $logger): self
     {
         return new self($logger);

src/Config/Resilient.php

@@ -6,10 +6,14 @@
 use Innmind\OperatingSystem\Config;
 use Innmind\HttpTransport\ExponentialBackoff;
 
+/**
+ * @psalm-immutable
+ */
 enum Resilient
 {
     case instance;
 
+    #[\NoDiscard]
     public function __invoke(Config $config): Config
     {
         return $config
@@ -21,7 +25,10 @@ public function __invoke(Config $config): Config
 
     /**
      * This config helps retry certain _safe_ operations on remote systems
+     *
+     * @psalm-pure
      */
+    #[\NoDiscard]
     public static function new(): self
     {
         return self::instance;

src/CurrentProcess.php

@@ -29,6 +29,7 @@ private function __construct(Halt $halt, Handler $handler)
     /**
      * @internal
      */
+    #[\NoDiscard]
     public static function of(Halt $halt, Handler $handler): self
     {
         return new self($halt, $handler);
@@ -37,6 +38,7 @@ public static function of(Halt $halt, Handler $handler): self
     /**
      * @return Attempt<Pid>
      */
+    #[\NoDiscard]
     public function id(): Attempt
     {
         $pid = \getmypid();
@@ -48,6 +50,7 @@ public function id(): Attempt
         };
     }
 
+    #[\NoDiscard]
     public function signals(): Signals
     {
         return $this->signals ??= Signals::of($this->handler);
@@ -56,11 +59,13 @@ public function signals(): Signals
     /**
      * @return Attempt<SideEffect>
      */
+    #[\NoDiscard]
     public function halt(Period $period): Attempt
     {
         return ($this->halt)($period);
     }
 
+    #[\NoDiscard]
     public function memory(): Bytes
     {
         /** @psalm-suppress ArgumentTypeCoercion */

src/Factory.php

@@ -5,6 +5,7 @@
 
 final class Factory
 {
+    #[\NoDiscard]
     public static function build(?Config $config = null): OperatingSystem
     {
         switch (\PHP_OS) {

src/Filesystem.php

@@ -41,6 +41,7 @@ private function __construct(Processes $processes, Config $config)
     /**
      * @internal
      */
+    #[\NoDiscard]
     public static function of(Processes $processes, Config $config): self
     {
         return new self($processes, $config);
@@ -49,6 +50,7 @@ public static function of(Processes $processes, Config $config): self
     /**
      * @return Attempt<Adapter>
      */
+    #[\NoDiscard]
     public function mount(Path $path): Attempt
     {
         /**
@@ -71,6 +73,7 @@ public function mount(Path $path): Attempt
             });
     }
 
+    #[\NoDiscard]
     public function contains(Path $path): bool
     {
         if (!\file_exists($path->toString())) {
@@ -87,6 +90,7 @@ public function contains(Path $path): bool
     /**
      * @return Maybe<mixed> Return the value returned by the file or nothing if the file doesn't exist
      */
+    #[\NoDiscard]
     public function require(Path $path): Maybe
     {
         $path = $path->toString();
@@ -104,6 +108,7 @@ public function require(Path $path): Maybe
         return Maybe::just(require $path);
     }
 
+    #[\NoDiscard]
     public function watch(Path $path): Ping
     {
         return ($this->watch)($path);
@@ -121,6 +126,7 @@ public function watch(Path $path): Ping
      *
      * @return Attempt<Content>
      */
+    #[\NoDiscard]
     public function temporary(Sequence $chunks): Attempt
     {
         return $this