Backport bless_tests.php changes from PHP 8

Author: nikic

scripts/dev/bless_tests.php

@@ -19,13 +19,26 @@
     }
 
     $phpt = file_get_contents($path);
+    $out = file_get_contents($outPath);
+
     if (false !== strpos($phpt, '--XFAIL--')) {
         // Don't modify expected output of XFAIL tests
         continue;
     }
 
-    $out = file_get_contents($outPath);
-    $out = normalizeOutput($out);
+    // Don't update EXPECTREGEX tests
+    if (!preg_match('/--EXPECT(F?)--(.*)$/s', $phpt, $matches)) {
+        continue;
+    }
+
+    $oldExpect = trim($matches[2]);
+    $isFormat = $matches[1] == 'F';
+    if ($isFormat) {
+        $out = generateMinimallyDifferingOutput($out, $oldExpect);
+    } else {
+        $out = normalizeOutput($out);
+    }
+
     $phpt = insertOutput($phpt, $out);
     file_put_contents($path, $phpt);
 }
@@ -62,9 +75,161 @@ function normalizeOutput(string $out): string {
     return $out;
 }
 
+function formatToRegex(string $format): string {
+    $result = preg_quote($format, '/');
+    $result = str_replace('%d', '\d+', $result);
+    $result = str_replace('%s', '[^\r\n]+', $result);
+    return "/^$result$/s";
+}
+
+function generateMinimallyDifferingOutput(string $out, string $oldExpect) {
+    $outLines = explode("\n", $out);
+    $oldExpectLines = explode("\n", $oldExpect);
+    $differ = new Differ(function($oldExpect, $new) {
+        if (strpos($oldExpect, '%') === false) {
+            return $oldExpect === $new;
+        }
+        return preg_match(formatToRegex($oldExpect), $new);
+    });
+    $diff = $differ->diff($oldExpectLines, $outLines);
+
+    $result = [];
+    foreach ($diff as $elem) {
+        if ($elem->type == DiffElem::TYPE_KEEP) {
+            $result[] = $elem->old;
+        } else if ($elem->type == DiffElem::TYPE_ADD) {
+            $result[] = normalizeOutput($elem->new);
+        }
+    }
+    return implode("\n", $result);
+}
+
 function insertOutput(string $phpt, string $out): string {
     return preg_replace_callback('/--EXPECTF?--.*$/s', function($matches) use($out) {
-        $F = strpos($out, '%') !== false ? 'F' : '';
+        $hasWildcard = preg_match('/%[resSaAwidxfc]/', $out);
+        $F = $hasWildcard ? 'F' : '';
         return "--EXPECT$F--\n" . $out . "\n";
     }, $phpt);
 }
+
+/**
+ * Implementation of the the Myers diff algorithm.
+ *
+ * Myers, Eugene W. "An O (ND) difference algorithm and its variations."
+ * Algorithmica 1.1 (1986): 251-266.
+ */
+
+class DiffElem
+{
+    const TYPE_KEEP = 0;
+    const TYPE_REMOVE = 1;
+    const TYPE_ADD = 2;
+
+    /** @var int One of the TYPE_* constants */
+    public $type;
+    /** @var mixed Is null for add operations */
+    public $old;
+    /** @var mixed Is null for remove operations */
+    public $new;
+
+    public function __construct(int $type, $old, $new) {
+        $this->type = $type;
+        $this->old = $old;
+        $this->new = $new;
+    }
+}
+
+class Differ
+{
+    private $isEqual;
+
+    /**
+     * Create differ over the given equality relation.
+     *
+     * @param callable $isEqual Equality relation with signature function($a, $b) : bool
+     */
+    public function __construct(callable $isEqual) {
+        $this->isEqual = $isEqual;
+    }
+
+    /**
+     * Calculate diff (edit script) from $old to $new.
+     *
+     * @param array $old Original array
+     * @param array $new New array
+     *
+     * @return DiffElem[] Diff (edit script)
+     */
+    public function diff(array $old, array $new) {
+        list($trace, $x, $y) = $this->calculateTrace($old, $new);
+        return $this->extractDiff($trace, $x, $y, $old, $new);
+    }
+
+    private function calculateTrace(array $a, array $b) {
+        $n = \count($a);
+        $m = \count($b);
+        $max = $n + $m;
+        $v = [1 => 0];
+        $trace = [];
+        for ($d = 0; $d <= $max; $d++) {
+            $trace[] = $v;
+            for ($k = -$d; $k <= $d; $k += 2) {
+                if ($k === -$d || ($k !== $d && $v[$k-1] < $v[$k+1])) {
+                    $x = $v[$k+1];
+                } else {
+                    $x = $v[$k-1] + 1;
+                }
+
+                $y = $x - $k;
+                while ($x < $n && $y < $m && ($this->isEqual)($a[$x], $b[$y])) {
+                    $x++;
+                    $y++;
+                }
+
+                $v[$k] = $x;
+                if ($x >= $n && $y >= $m) {
+                    return [$trace, $x, $y];
+                }
+            }
+        }
+        throw new \Exception('Should not happen');
+    }
+
+    private function extractDiff(array $trace, int $x, int $y, array $a, array $b) {
+        $result = [];
+        for ($d = \count($trace) - 1; $d >= 0; $d--) {
+            $v = $trace[$d];
+            $k = $x - $y;
+
+            if ($k === -$d || ($k !== $d && $v[$k-1] < $v[$k+1])) {
+                $prevK = $k + 1;
+            } else {
+                $prevK = $k - 1;
+            }
+
+            $prevX = $v[$prevK];
+            $prevY = $prevX - $prevK;
+
+            while ($x > $prevX && $y > $prevY) {
+                $result[] = new DiffElem(DiffElem::TYPE_KEEP, $a[$x-1], $b[$y-1]);
+                $x--;
+                $y--;
+            }
+
+            if ($d === 0) {
+                break;
+            }
+
+            while ($x > $prevX) {
+                $result[] = new DiffElem(DiffElem::TYPE_REMOVE, $a[$x-1], null);
+                $x--;
+            }
+
+            while ($y > $prevY) {
+                $result[] = new DiffElem(DiffElem::TYPE_ADD, null, $b[$y-1]);
+                $y--;
+            }
+        }
+        return array_reverse($result);
+    }
+}