Added FixerBlame tool and one test

src/ExperimentalLineNumberTool/CodeChange.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of PHP CS Fixer.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *     Dariusz Rumiński <dariusz.ruminski@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace PhpCsFixer\ExperimentalLineNumberTool;
+
+final class CodeChange
+{
+    public string $content;
+    public int $change;
+    public ?int $newLineNumber = null;
+    public ?int $oldLineNumber = null;
+}

src/ExperimentalLineNumberTool/FixerBlame.php

@@ -0,0 +1,312 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of PHP CS Fixer.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *     Dariusz Rumiński <dariusz.ruminski@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace PhpCsFixer\ExperimentalLineNumberTool;
+
+use PhpCsFixer\AbstractFixer;
+use PhpCsFixer\Tokenizer\Tokens;
+use SebastianBergmann\Diff\Differ;
+use SebastianBergmann\Diff\Output\StrictUnifiedDiffOutputBuilder;
+
+final class FixerBlame
+{
+    private Differ $differ;
+
+    /**
+     * @var array<array{
+     *     fixerName: string,
+     *     source: string
+     *     }>
+     */
+    private array $changeStack = [];
+
+    public function __construct()
+    {
+        $this->differ = new Differ(new StrictUnifiedDiffOutputBuilder([
+            'collapseRanges' => true,
+            'commonLineThreshold' => 1,
+            'contextLines' => 1,
+            'fromFile' => 'Original',
+            'toFile' => 'New',
+        ]));
+    }
+
+    public function originalCode($code): void
+    {
+        if ($code instanceof Tokens) {
+            $code = $code->generateCode();
+        }
+
+        $this->changeStack[] = [
+            'fixerName' => '__initial__',
+            'source' => $code,
+        ];
+    }
+
+    public function snapshotCode(string $fixerName, string $source): void
+    {
+        $this->changeStack[] = [
+            'fixerName' => $fixerName,
+            'source' => $source,
+        ];
+    }
+
+    public function snapshotTokens(AbstractFixer $fixer, Tokens $tokens): void
+    {
+        $this->changeStack[] = [
+            'fixerName' => $fixer->getName(),
+            'source' => $tokens->generateCode(),
+        ];
+    }
+
+    /**
+     * @return array<FixerChange>
+     */
+    public function calculateChanges(): array
+    {
+        $changes = [];
+
+        foreach ($this->changeStack as $changeIndex => $change) {
+            if (0 === $changeIndex) {
+                continue;
+            }
+
+            $oldChangeContent = $this->changeStack[$changeIndex - 1]['source'];
+            $newChangeContent = $change['source'];
+
+            $fixerName = $change['fixerName'];
+
+            $diffResults = $this->diff($oldChangeContent, $newChangeContent);
+            $patches = $this->findPatches($diffResults);
+
+            foreach ($patches as $patchInfo) {
+                $patchContent = $patchInfo->getPatchContent($diffResults);
+
+                $numberOfChanges = \count($patchContent);
+
+                // simple remove
+                if (1 === $numberOfChanges && Differ::REMOVED === $patchContent[0]->change) {
+                    $changes[] = [
+                        'fixerName' => $fixerName,
+                        'start' => $patchContent[0]->oldLineNumber,
+                        'changedSum' => $patchInfo->getChangeSum(),
+                        'changedAt' => 0,
+                    ];
+
+                    continue;
+                }
+
+                // line changed
+                if (2 === $numberOfChanges && Differ::REMOVED === $patchContent[0]->change && Differ::ADDED === $patchContent[1]->change) {
+                    $addedLine = $patchContent[1]->content;
+                    $removedLine = $patchContent[0]->content;
+
+                    $changedAt = null;
+
+                    for ($i = 0; $i < min(\strlen($addedLine), \strlen($removedLine)); ++$i) {
+                        if ($addedLine[$i] !== $removedLine[$i]) {
+                            $changedAt = $i + 1;
+
+                            break;
+                        }
+                    }
+
+                    $changes[] = [
+                        'fixerName' => $fixerName,
+                        'start' => $patchContent[0]->oldLineNumber,
+                        'changedSum' => $patchInfo->getChangeSum(),
+                        'changedAt' => $changedAt ?? \strlen($removedLine) + 1,
+                    ];
+
+                    continue;
+                }
+
+                $onlyRemove = 0x1;
+                $onlyAdd = 0x1;
+
+                foreach ($patchContent as $patchRow) {
+                    if (Differ::ADDED === $patchRow->change) {
+                        $onlyAdd &= 0x1;
+                    } else {
+                        $onlyAdd &= 0;
+                    }
+
+                    if (Differ::REMOVED === $patchRow->change) {
+                        $onlyRemove &= 0x1;
+                    } else {
+                        $onlyRemove &= 0;
+                    }
+                }
+
+                if (1 === $onlyAdd xor 1 === $onlyRemove) {
+                    if (1 === $onlyAdd) {
+                        $lineNumber = $patchContent[0]->newLineNumber;
+                    } else {
+                        $lineNumber = $patchContent[0]->oldLineNumber;
+                    }
+
+                    $changes[] = [
+                        'fixerName' => $fixerName,
+                        'start' => $lineNumber,
+                        'changedSum' => $patchInfo->getChangeSum(),
+                        'changedAt' => 0,
+                    ];
+
+                    continue;
+                }
+                if (Differ::ADDED === $patchContent[0]->change) {
+                    throw new \RuntimeException('added lines first?');
+                }
+
+                $changes[] = [
+                    'fixerName' => $fixerName,
+                    'start' => $patchContent[0]->oldLineNumber,
+                    'changedSum' => $patchInfo->getChangeSum(),
+                    'changedAt' => 0,
+                ];
+
+                continue;
+
+                throw new \RuntimeException('unhandled case');
+            }
+        }
+
+        $changeSet = [];
+        foreach ($changes as $index => $change) {
+            $lineChanges = 0;
+            for ($i = $index - 1; $i >= 0; --$i) {
+                if ($changes[$i]['start'] >= $change['start']) {
+                    continue;
+                }
+
+                $lineChanges -= $changes[$i]['changedSum'];
+            }
+
+            $changeSet[] = new FixerChange($change['fixerName'], $change['start'] + $lineChanges, $change['changedAt']);
+        }
+
+        return $changeSet;
+    }
+
+    /**
+     * @return array<CodeChange>
+     */
+    private function diff(string $oldCode, string $newCode): array
+    {
+        $diffResults = $this->differ->diffToArray($oldCode, $newCode);
+
+        $linePointerInOldContent = 1;
+        $linePointerInNewContent = 1;
+
+        $buffer = [];
+        foreach ($diffResults as $diffResult) {
+            if (Differ::ADDED === $diffResult[1]) {
+                $diff = new CodeChange();
+                $diff->content = $diffResult[0];
+                $diff->change = Differ::ADDED;
+                $diff->newLineNumber = $linePointerInNewContent++;
+
+                $buffer[] = $diff;
+
+                continue;
+            }
+
+            if (Differ::REMOVED === $diffResult[1]) {
+                $diff = new CodeChange();
+                $diff->content = $diffResult[0];
+                $diff->change = Differ::REMOVED;
+                $diff->oldLineNumber = $linePointerInOldContent++;
+
+                $buffer[] = $diff;
+
+                continue;
+            }
+
+            $diff = new CodeChange();
+            $diff->content = $diffResult[0];
+            $diff->change = Differ::OLD;
+            $diff->newLineNumber = $linePointerInNewContent++;
+            $diff->oldLineNumber = $linePointerInOldContent++;
+
+            $buffer[] = $diff;
+        }
+
+        return $buffer;
+    }
+
+    /**
+     * @param array<CodeChange> $diffs
+     *
+     * @return array<PatchInfo>
+     */
+    private function findPatches(array $diffs): array
+    {
+        /** @var array<PatchInfo> $patches */
+        $patches = [];
+        $patchInfo = null;
+        $state = 'file_start';
+
+        foreach ($diffs as $key => $diffResult) {
+            if ('file_start' === $state) {
+                if (Differ::OLD === $diffResult->change) {
+                    $state = 'between_patch';
+
+                    continue;
+                }
+
+                if (Differ::ADDED === $diffResult->change || Differ::REMOVED === $diffResult->change) {
+                    $patchInfo = new PatchInfo();
+                    $patchInfo->startKey = $key;
+                    $patchInfo->countChange($diffResult->change);
+
+                    $state = 'in_patch';
+
+                    continue;
+                }
+            }
+
+            if ('between_patch' === $state && (Differ::ADDED === $diffResult->change || Differ::REMOVED === $diffResult->change)) {
+                $patchInfo = new PatchInfo();
+                $patchInfo->startKey = $key;
+                $patchInfo->countChange($diffResult->change);
+
+                $state = 'in_patch';
+
+                continue;
+            }
+
+            if ('in_patch' === $state && Differ::OLD === $diffResult->change) {
+                $state = 'between_patch';
+
+                $patchInfo->endKey = $key;
+                $patches[] = $patchInfo;
+                $patchInfo = null;
+
+                continue;
+            }
+
+            if ('in_patch' === $state) {
+                $patchInfo->countChange($diffResult->change);
+            }
+        }
+
+        if ('in_patch' === $state) {
+            $patchInfo->endKey = \count($diffs) - 1;
+            $patches[] = $patchInfo;
+            $patchInfo = null;
+        }
+
+        return $patches;
+    }
+}

src/ExperimentalLineNumberTool/FixerChange.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of PHP CS Fixer.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *     Dariusz Rumiński <dariusz.ruminski@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace PhpCsFixer\ExperimentalLineNumberTool;
+
+final class FixerChange
+{
+    public string $fixerName;
+
+    public int $line;
+
+    public int $char = 0;
+
+    public function __construct(
+        string $fixerName,
+        int $line,
+        int $char = 0
+    ) {
+        $this->fixerName = $fixerName;
+        $this->line = $line;
+        $this->char = $char;
+    }
+}