git/GitDiff.php

		$vDiffOld = new VirtualDiffFile( $path, $oldContent );
		$vDiffNew = new VirtualDiffFile( $path, $newContent );
		-
		- $isBinary = ($newSha !== '' && $vDiffNew->isBinary()) \|\|
		- ($newSha === '' && $oldSha !== '' && $vDiffOld->isBinary());
		+ $isBinary = ($newSha !== '' && $vDiffNew->isBinary()) \|\|
		+ ($newSha === '' && $oldSha !== '' && $vDiffOld->isBinary());

		$result = [

		$oldLines = explode( "\n", str_replace( "\r\n", "\n", $old ) );
		$newLines = explode( "\n", str_replace( "\r\n", "\n", $new ) );
		-
		- unset( $old, $new );
		-
		- $m = count( $oldLines );
		- $n = count( $newLines );
		- $start = 0;
		- $end = 0;
		+ $m = count( $oldLines );
		+ $n = count( $newLines );
		+ $start = 0;
		+ $end = 0;

		while( $start < $m && $start < $n &&

		$oldSlice = array_slice( $oldLines, $start, $m - $start - $end );
		$newSlice = array_slice( $newLines, $start, $n - $start - $end );
		- $result = [];
		-
		- unset( $oldLines, $newLines );
		-
		$countOld = count( $oldSlice );
		$countNew = count( $newSlice );
		$limit = 100000;
		+ $result = [];

		- if( ( $countOld * $countNew ) > $limit ) {
		- error_log( "Diff complexity too high: $countOld * $countNew > $limit" );
		- $result = [[ 't' => 'gap' ]];
		+ if( ($countOld * $countNew) > $limit ) {
		+ $result = $this->buildFallbackDiff( $oldSlice, $newSlice, $start );
		} else {
		$ops = $this->computeLCS( $oldSlice, $newSlice );
		- $stream = $this->buildDiffStream(
		- $ops,
		- $oldSlice,
		- $start,
		- $m,
		- $end
		- );
		+ $stream = $this->buildDiffStream( $ops, $start );
		$result = $this->formatDiffOutput( $stream );
		}

		return $result;
		}

		- private function buildDiffStream(
		- array $ops,
		- array $oldSlice,
		- int $start,
		- int $m,
		- int $end
		+ private function buildFallbackDiff(
		+ array $old,
		+ array $new,
		+ int $offset
		): array {
		+ $stream = [];
		+ $currO = $offset + 1;
		+ $currN = $offset + 1;
		+
		+ foreach( $old as $line ) {
		+ $stream[] = [ 't' => '-', 'l' => $line, 'no' => $currO++, 'nn' => null ];
		+ }
		+
		+ foreach( $new as $line ) {
		+ $stream[] = [ 't' => '+', 'l' => $line, 'no' => null, 'nn' => $currN++ ];
		+ }
		+
		+ return $stream;
		+ }
		+
		+ private function buildDiffStream( array $ops, int $start ): array {
		$stream = [];
		$currO = $start + 1;
		$currN = $start + 1;

		foreach( $ops as $op ) {
		- if( $op['t'] === ' ' ) {
		- $stream[] = [
		- 't' => ' ', 'l' => $op['l'], 'no' => $currO++, 'nn' => $currN++
		- ];
		- } elseif( $op['t'] === '-' ) {
		- $stream[] = [
		- 't' => '-', 'l' => $op['l'], 'no' => $currO++, 'nn' => null
		- ];
		- } elseif( $op['t'] === '+' ) {
		- $stream[] = [
		- 't' => '+', 'l' => $op['l'], 'no' => null, 'nn' => $currN++
		- ];
		- }
		+ $stream[] = [
		+ 't' => $op['t'],
		+ 'l' => $op['l'],
		+ 'no' => $op['t'] === '+' ? null : $currO++,
		+ 'nn' => $op['t'] === '-' ? null : $currN++
		+ ];
		}


		for( $i = 0; $i < $n; $i++ ) {
		if( $stream[$i]['t'] !== ' ' ) {
		- $start = max( 0, $i - $context );
		- $end = min( $n - 1, $i + $context );
		+ $low = max( 0, $i - $context );
		+ $high = min( $n - 1, $i + $context );

		- for( $j = $start; $j <= $end; $j++ ) {
		+ for( $j = $low; $j <= $high; $j++ ) {
		$keep[$j] = true;
		}

		$i--;
		$j--;
		- } elseif( $j > 0 &&
		- ($i === 0 \|\| $c[$i][$j - 1] >= $c[$i - 1][$j]) ) {
		+ } elseif( $j > 0 && ($i === 0 \|\| $c[$i][$j - 1] >= $c[$i - 1][$j]) ) {
		$diff[] = [ 't' => '+', 'l' => $new[$j - 1] ];
		$j--;
		} elseif( $i > 0 && ($j === 0 \|\| $c[$i][$j - 1] < $c[$i - 1][$j]) ) {
		$diff[] = [ 't' => '-', 'l' => $old[$i - 1] ];
		$i--;
		}
		}

		return array_reverse( $diff );
		- }
		-}
		-
		-class VirtualDiffFile extends File {
		- public function __construct( string $name, string $content ) {
		- parent::__construct(
		- $name,
		- '',
		- '100644',
		- 0,
		- strlen( $content ),
		- $content
		- );
		}
		}

Adds fallback mechanism for large gaps in diffs

Author	Dave Jarvis <email>
Date	2026-02-18 17:22:35 GMT-0800
Commit	644dbda513ca85ffc8c7b5509579d517b26ba506
Parent	f3507ba
Delta	40 lines added, 61 lines removed, 21-line decrease