Fix some phpstan findings

Author: SpacePossum

phpstan.neon

@@ -1,5 +1,9 @@
 parameters:
-    level: 2
+    level: 5
     paths:
         - src
         - tests
+    ignoreErrors:
+        -
+            message: '#Method SebastianBergmann\\Diff\\Differ::calculateEstimatedFootprint\(\) never returns float so it can be removed from the return type\.#'
+            path: src/Differ.php

src/Differ.php

@@ -84,11 +84,11 @@ public function diffToArray(array|string $from, array|string $to, ?LongestCommon
         reset($to);
 
         foreach ($common as $token) {
-            while (($fromToken = reset($from)) !== $token) {
+            while ((/* from-token */ reset($from)) !== $token) {
                 $diff[] = [array_shift($from), self::REMOVED];
             }
 
-            while (($toToken = reset($to)) !== $token) {
+            while ((/* to-token */ reset($to)) !== $token) {
                 $diff[] = [array_shift($to), self::ADDED];
             }
 

src/MemoryEfficientLongestCommonSubsequenceCalculator.php

@@ -15,7 +15,6 @@
 use function array_slice;
 use function count;
 use function in_array;
-use function max;
 
 final class MemoryEfficientLongestCommonSubsequenceCalculator implements LongestCommonSubsequenceCalculator
 {

src/Output/AbstractChunkOutputBuilder.php

@@ -16,6 +16,8 @@ abstract class AbstractChunkOutputBuilder implements DiffOutputBuilderInterface
     /**
      * Takes input of the diff array and returns the common parts.
      * Iterates through diff line by line.
+     *
+     * @return array<int, positive-int>
      */
     protected function getCommonChunks(array $diff, int $lineThreshold = 5): array
     {

src/Output/DiffOnlyOutputBuilder.php

@@ -9,9 +9,11 @@
  */
 namespace SebastianBergmann\Diff\Output;
 
+use function assert;
 use function fclose;
 use function fopen;
 use function fwrite;
+use function is_resource;
 use function str_ends_with;
 use function stream_get_contents;
 use function substr;
@@ -33,6 +35,7 @@ public function __construct(string $header = "--- Original\n+++ New\n")
     public function getDiff(array $diff): string
     {
         $buffer = fopen('php://memory', 'r+b');
+        assert(is_resource($buffer));
 
         if ('' !== $this->header) {
             fwrite($buffer, $this->header);

src/Output/StrictUnifiedDiffOutputBuilder.php

@@ -11,12 +11,14 @@
 
 use function array_merge;
 use function array_splice;
+use function assert;
 use function count;
 use function fclose;
 use function fopen;
 use function fwrite;
 use function is_bool;
 use function is_int;
+use function is_resource;
 use function is_string;
 use function max;
 use function min;
@@ -99,6 +101,8 @@ public function getDiff(array $diff): string
         $this->changed = false;
 
         $buffer = fopen('php://memory', 'r+b');
+        assert(is_resource($buffer));
+
         fwrite($buffer, $this->header);
 
         $this->writeDiffHunks($buffer, $diff);

src/Output/UnifiedDiffOutputBuilder.php

@@ -10,10 +10,12 @@
 namespace SebastianBergmann\Diff\Output;
 
 use function array_splice;
+use function assert;
 use function count;
 use function fclose;
 use function fopen;
 use function fwrite;
+use function is_resource;
 use function max;
 use function min;
 use function str_ends_with;
@@ -45,6 +47,7 @@ public function __construct(string $header = "--- Original\n+++ New\n", bool $ad
     public function getDiff(array $diff): string
     {
         $buffer = fopen('php://memory', 'r+b');
+        assert(is_resource($buffer));
 
         if ('' !== $this->header) {
             fwrite($buffer, $this->header);

src/Parser.php

@@ -71,6 +71,9 @@ public function parse(string $string): array
         return $diffs;
     }
 
+    /**
+     * @param string[] $lines
+     */
     private function parseFileDiff(Diff $diff, array $lines): void
     {
         $chunks    = [];

src/TimeEfficientLongestCommonSubsequenceCalculator.php

@@ -11,7 +11,6 @@
 
 use function array_reverse;
 use function count;
-use function max;
 use SplFixedArray;
 
 final class TimeEfficientLongestCommonSubsequenceCalculator implements LongestCommonSubsequenceCalculator

tests/DifferTest.php

@@ -189,6 +189,15 @@ public static function arrayProvider(): array
         ];
     }
 
+    /**
+     * @return array<
+     *     array{
+     *         0: string,
+     *         1: string,
+     *         2: string,
+     *     }
+     * >
+     */
     public static function textProvider(): array
     {
         return [
@@ -255,6 +264,14 @@ public static function textProvider(): array
         ];
     }
 
+    /**
+     * @return array<
+     *     array{
+     *         0: array<string>,
+     *         1: string,
+     *     }
+     * >
+     */
     public static function provideSplitStringByLinesCases(): array
     {
         return [
@@ -368,7 +385,6 @@ public function testSplitStringByLines(array $expected, string $input): void
     {
         $reflection = new ReflectionObject($this->differ);
         $method     = $reflection->getMethod('splitStringByLines');
-        $method->setAccessible(true);
 
         $this->assertSame($expected, $method->invoke($this->differ, $input));
     }