Repository Analysis

sebastianbergmann/diff

Diff implementation

9.5 Low AI signal View on GitHub

Analysis Overview

This report presents the forensic synthetic code analysis of sebastianbergmann/diff, a PHP project with 7,656 GitHub stars. SynthScan v2.0 examined 6,324 lines of code across 44 source files, recording 60 pattern matches distributed across 1 syntactic category. The overall adjusted score of 9.5 places this repository in the Low AI signal band.

The scanner applied 160+ deterministic lexical heuristics, multi-line block detectors, abstract syntax tree depth profilers, and a cross-file Jaccard similarity matrix to construct a statistically normalised synthetic code estimate. All matches are individually weighted by severity coefficient and contextual multiplier before summation, and the resulting headline score is temporally discounted to account for the repository's development history relative to the commercial emergence of large language model coding tooling (November 2022 onward).

9.5
Adjusted Score
9.5
Raw Score
100%
Time Factor
2026-07-30
Last Push
7.7K
Stars
PHP
Language
6.3K
Lines of Code
44
Files
60
Pattern Hits
2026-08-02
Scan Date
0.00
HC Hit Rate

What These Metrics Mean

Adjusted Score
Primary synthetic code indicator. Raw score normalised per 1,000 lines of code and multiplied by the temporal discount factor. This is the definitive comparative metric — use it to rank repositories by AI authorship density.
Raw Score
The unmodified sum of all severity-weighted, context-multiplied pattern match scores before temporal discounting. Reflects the absolute signal strength independent of when the repository was last active.
Time Factor
The temporal discount multiplier (0–100%) applied to the raw score. Repositories last updated before ChatGPT's launch (Nov 2022) receive a 5% factor. Full signal is only assigned to repositories active in the post-adoption era (Jan 2024+).
Pattern Hits
Total count of individual pattern matches across all files and categories. A high hit count with a low score may indicate a very large codebase with isolated AI snippets; a low count with a high score indicates dense, concentrated AI signatures.
HC Hit Rate
High+Critical pattern hits per file, averaged across the repository. This orthogonal signal catches repositories where a few files are densely packed with high-severity AI tells — a strong indicator even when the normalised score appears moderate due to codebase size.
Lines of Code / Files
Total lines and files analysed. The scanner examines 94 file extensions. These denominators are used to normalise the score, enabling fair comparison between repositories of vastly different sizes.

Score History

Longitudinal tracking requires multiple scan runs. Once this repository is re-scanned after new commits land, this chart will visualise how the synthetic code signal evolves over time — enabling you to detect whether AI authorship is growing, stabilising, or being actively corrected by human engineers.

No multi-scan history yet — run the scanner again to build trend data.

Severity Breakdown

Classifies detected patterns by their diagnostic confidence and structural impact. CRITICAL patterns (coefficient 10) represent definitive synthetic signatures — hallucinated imports, explicit LLM attribution metadata — virtually never produced by human authors. HIGH (5) indicates strong structural tells such as cross-file repetition or cross-linguistic idioms. MEDIUM (2) covers recognisable conversational padding and AI-specific vocabulary. LOW (1) captures subtle indicators like tautological comments and generic boilerplate that require density to carry independent signal.

CRITICAL 0HIGH 0MEDIUM 0LOW 60

Directory Score Breakdown

This horizontal bar chart decomposes the repository's raw synthetic code score by top-level directory, allowing you to pinpoint precisely which modules or components carry the highest AI authorship density. Directories with disproportionately high scores relative to their size warrant targeted manual review: concentrated AI signatures often trace back to mass-generated configuration layers, auto-ported test suites, LLM-scaffolded boilerplate classes, or entire subsystems authored under heavy copilot assistance. Use this view to prioritise your human code-review effort.

Pattern Findings

The scanner identified 60 distinct pattern matches across 1 syntactic category. Each entry below represents a discrete location in the source code where the engine recorded a statistically significant AI authorship indicator. Expand any category row to inspect the individual file paths, line numbers, code snippets, and the lexical context (CODE, COMMENT, or STRING) in which each match was detected.

Reading the findings table: The Severity column indicates the diagnostic confidence level (CRITICAL / HIGH / MEDIUM / LOW). The Context column identifies whether the match occurred inside executable code, an inline comment, or a string literal — comment-context matches receive a ×1.5 weight because LLMs systematically over-annotate. The ⚡ bolt icon marks clustered matches: three or more patterns within a 10-line window, each receiving an additional ×1.5 density multiplier as dense clusters constitute far stronger evidence of synthetic authorship than isolated hits.

Hyper-Verbose Identifiers60 hits · 60 pts
SeverityFileLineSnippetContext
LOWREADME.md119 [content:SebastianBergmann\Diff\Line:private] => public function tesCODE
LOWREADME.md125 [content:SebastianBergmann\Diff\Line:private] => public function tesCODE
LOWtests/MyersDiffTest.php64 public function testCompletelyDistinctSequences(): voidCODE
LOWtests/MyersDiffTest.php81 public function testSingleSubstitutionInMiddle(): voidCODE
LOWtests/MyersDiffTest.php145 public function testReversedSequenceProducesOptimalEditDistance(): voidCODE
LOWtests/DiffTest.php22 public function testGettersAfterConstructionWithDefault(): voidCODE
LOWtests/DiffTest.php33 public function testGettersAfterConstructionWithChunks(): voidCODE
LOWtests/DiffTest.php46 public function testSetChunksAfterConstruction(): voidCODE
LOWtests/ParserTest.php81 public function testParseWithMultipleChunks(): voidCODE
LOWtests/ParserTest.php106 public function testParseWithSpacesInFileNames(): voidCODE
LOWtests/ParserTest.php128 public function testParseWithSpacesInFileNamesAndTimestamp(): voidCODE
LOWtests/ParserTest.php149 public function testParseWithRemovedLines(): voidCODE
LOWtests/ParserTest.php189 public function testParseDiffForMultipleFiles(): voidCODE
LOWtests/DifferTest.php275 public static function provideSplitStringByLinesCases(): arrayCODE
LOWtests/DifferTest.php359 public function testArrayRepresentationOfDiffCanBeRendered(array $expected, array|string $from, array|string $to): vCODE
LOWtests/DifferTest.php365 public function testTextRepresentationOfDiffCanBeRendered(string $expected, string $from, string $to): voidCODE
LOWtests/Output/DiffOnlyOutputBuilderTest.php34 public static function textForNoNonDiffLinesProvider(): arrayCODE
LOWtests/Output/DiffOnlyOutputBuilderTest.php73 public function testDiffDoNotShowNonDiffLines(string $expected, string $from, string $to, string $header = ''): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php38 public static function provideOutputBuildingCases(): arrayCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php54 public static function provideBasicDiffGeneration(): arrayCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php72 public static function provideConfiguredDiffGeneration(): arrayCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php222 public static function provideInvalidConfiguration(): arrayCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php283 public static function provideCommonLineThresholdCases(): arrayCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php331 public static function provideContextLineConfigurationCases(): arrayCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php596 public function testConfiguredDiffGeneration(string $expected, string $from, string $to, array $config = []): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php646 public function testCustomHeaderCanBeProvided(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php658 public function testCustomHeaderTakesPrecedenceOverFromFileAndToFile(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php674 public function testCustomHeaderWithoutTrailingNewlineGetsOneAppended(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php686 public function testLineNumbersCanBeOmittedFromHunkHeader(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php700 public function testNoLineEndEofWarningCanBeSuppressed(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php714 public function testDiffLineEndWarningIsEmittedWhenEnabled(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php729 public function testDiffLineEndWarningIsSuppressedByDefault(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php742 public function testInvalidAddLineNumbersOptionIsRejected(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php754 public function testInvalidEmitNoLineEndEofWarningOptionIsRejected(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php766 public function testInvalidEmitDiffLineEndWarningOptionIsRejected(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php778 public function testInvalidHeaderOptionIsRejected(): voidCODE
LOWtests/Output/StrictUnifiedDiffOutputBuilderTest.php813 public function testContextLineConfiguration(string $expected, string $from, string $to, int $contextLines, int $comCODE
LOW…/Output/StrictUnifiedDiffOutputBuilderDataProvider.php30 public static function provideOutputBuildingCases(): arrayCODE
LOW…/Output/StrictUnifiedDiffOutputBuilderDataProvider.php138 public static function provideBasicDiffGeneration(): arrayCODE
LOW…tion/StrictUnifiedDiffOutputBuilderIntegrationTest.php52 public static function provideOutputBuildingCases(): arrayCODE
LOW…tion/StrictUnifiedDiffOutputBuilderIntegrationTest.php68 public static function provideBasicDiffGeneration(): arrayCODE
LOW…tion/StrictUnifiedDiffOutputBuilderIntegrationTest.php129 public function testIntegrationUsingPHPFileInVendorGitApply(string $fileFrom, string $fileTo): voidCODE
LOW…tion/StrictUnifiedDiffOutputBuilderIntegrationTest.php147 public function testIntegrationUsingPHPFileInVendorPatch(string $fileFrom, string $fileTo): voidCODE
LOW…tion/StrictUnifiedDiffOutputBuilderIntegrationTest.php170 public function testIntegrationOfUnitTestCasesGitApply(string $expected, string $from, string $to, ?array $options =CODE
LOW…tion/StrictUnifiedDiffOutputBuilderIntegrationTest.php181 public function testIntegrationOfUnitTestCasesPatch(string $expected, string $from, string $to, ?array $options = nuCODE
LOW…tion/StrictUnifiedDiffOutputBuilderIntegrationTest.php187 public function testIntegrationDiffOutputBuilderVersusDiffCommand(string $diff, string $from, string $to): voidCODE
LOW…tion/StrictUnifiedDiffOutputBuilderIntegrationTest.php214 private function doIntegrationTestGitApply(string $diff, string $from): voidCODE
LOWtests/Utils/UnifiedDiffAssertTraitTest.php69 public function testInvalidStartWithoutHeader(): voidCODE
LOWtests/Utils/UnifiedDiffAssertTraitTest.php302 public function testUnexpectedDuplicateNoNewLineEOF(): voidCODE
LOWtests/Utils/UnifiedDiffAssertTraitTest.php388 public function testUnexpectedEOFFromMissingLines(): voidCODE
LOWtests/Utils/UnifiedDiffAssertTraitTest.php404 public function testUnexpectedEOFToMissingLines(): voidCODE
LOWtests/Utils/UnifiedDiffAssertTraitTest.php420 public function testUnexpectedEOFBothFromAndToMissingLines(): voidCODE
LOWtests/Utils/UnifiedDiffAssertTrait.php30 public function assertValidUnifiedDiffFormat(string $diff): voidCODE
LOWtests/Utils/UnifiedDiffAssertTrait.php189 private function unifiedDiffAssertLinePrefix(string $line, string $message): stringCODE
LOWtests/Utils/UnifiedDiffAssertTrait.php205 private function unifiedDiffAssertStrLength(string $line, int $min, string $message): voidCODE
LOWtests/Utils/UnifiedDiffAssertTrait.php221 private function unifiedDiffAssertHeaderLine(string $line, string $start, string $message): voidCODE
LOWtests/Utils/UnifiedDiffAssertTrait.php245 private function unifiedDiffAssertHeaderDate(string $date, string $message): voidCODE
LOWtests/Utils/UnifiedDiffAssertTrait.php264 private function unifiedDiffAssertHunkHeader(string $line, string $message): arrayCODE
LOWtests/Exception/ConfigurationExceptionTest.php22 public function testConstructWithDefaults(): voidCODE
LOWsrc/Differ.php110 private function detectUnmatchedLineEndings(array $diff): boolCODE