# sebastian/diff

Diff implementation for PHP, factored out of PHPUnit into a stand-alone component.

## Installation

You can add this library as a local, per-project dependency to your project using [Composer](https://getcomposer.org/):

composer require sebastian/diff

If you only need this library during development, for instance to run your project's test suite, then you should add it as a development-time dependency:

composer require --dev sebastian/diff

### Usage

#### Generating diff

The `Differ` class can be used to generate a textual representation of the difference between two strings:

```php
<?php
use SebastianBergmann\Diff\Differ;

$differ = new Differ;
print $differ->diff('foo', 'bar');
```

The code above yields the output below:

--- Original
+++ New
@@ @@
-foo
+bar

There are three output builders available in this package:

#### UnifiedDiffOutputBuilder

This is default builder, which generates the output close to udiff and is used by PHPUnit.

```php
<?php

use SebastianBergmann\Diff\Differ;
use SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder;

$builder = new UnifiedDiffOutputBuilder(
"--- Original\n+++ New\n", // custom header
false // do not add line numbers to the diff
);

$differ = new Differ($builder);
print $differ->diff('foo', 'bar');
```

#### StrictUnifiedDiffOutputBuilder

Generates (strict) Unified diff's (unidiffs) with hunks,
similar to `diff -u` and compatible with `patch` and `git apply`.

```php
<?php

use SebastianBergmann\Diff\Differ;
use SebastianBergmann\Diff\Output\StrictUnifiedDiffOutputBuilder;

$builder = new StrictUnifiedDiffOutputBuilder([
'collapseRanges' => true, // ranges of length one are rendered with the trailing `,1`
'commonLineThreshold' => 6, // number of same lines before ending a new hunk and creating a new one (if needed)
'contextLines' => 3, // like `diff: -u, -U NUM, --unified[=NUM]`, for patch/git apply compatibility best to keep at least @ 3
'fromFile' => null,
'fromFileDate' => null,
'toFile' => null,
'toFileDate' => null,
]);

$differ = new Differ($builder);
print $differ->diff('foo', 'bar');
```

#### DiffOnlyOutputBuilder

Output only the lines that differ.

```php
<?php

use SebastianBergmann\Diff\Differ;
use SebastianBergmann\Diff\Output\DiffOnlyOutputBuilder;

$builder = new DiffOnlyOutputBuilder(
"--- Original\n+++ New\n"
);

$differ = new Differ($builder);
print $differ->diff('foo', 'bar');
```

#### DiffOutputBuilderInterface

You can pass any output builder to the `Differ` class as longs as it implements the `DiffOutputBuilderInterface`.

#### Parsing diff

The `Parser` class can be used to parse a unified diff into an object graph:

```php
use SebastianBergmann\Diff\Parser;
use SebastianBergmann\Git;

$git = new Git('/usr/local/src/money');

$diff = $git->getDiff(
'948a1a07768d8edd10dcefa8315c1cbeffb31833',
'c07a373d2399f3e686234c4f7f088d635eb9641b'
);

$parser = new Parser;

print_r($parser->parse($diff));
```

The code above yields the output below:

Array
(
[0] => SebastianBergmann\Diff\Diff Object
(
[from:SebastianBergmann\Diff\Diff:private] => a/tests/MoneyTest.php
[to:SebastianBergmann\Diff\Diff:private] => b/tests/MoneyTest.php
[chunks:SebastianBergmann\Diff\Diff:private] => Array
(
[0] => SebastianBergmann\Diff\Chunk Object
(
[start:SebastianBergmann\Diff\Chunk:private] => 87
[startRange:SebastianBergmann\Diff\Chunk:private] => 7
[end:SebastianBergmann\Diff\Chunk:private] => 87
[endRange:SebastianBergmann\Diff\Chunk:private] => 7
[lines:SebastianBergmann\Diff\Chunk:private] => Array
(
[0] => SebastianBergmann\Diff\Line Object
(
[type:SebastianBergmann\Diff\Line:private] => 3
[content:SebastianBergmann\Diff\Line:private] => * @covers SebastianBergmann\Money\Money::add
)

[1] => SebastianBergmann\Diff\Line Object
(
[type:SebastianBergmann\Diff\Line:private] => 3
[content:SebastianBergmann\Diff\Line:private] => * @covers SebastianBergmann\Money\Money::newMoney
)

[2] => SebastianBergmann\Diff\Line Object
(
[type:SebastianBergmann\Diff\Line:private] => 3
[content:SebastianBergmann\Diff\Line:private] => */
)

[3] => SebastianBergmann\Diff\Line Object
(
[type:SebastianBergmann\Diff\Line:private] => 2
[content:SebastianBergmann\Diff\Line:private] => public function testAnotherMoneyWithSameCurrencyObjectCanBeAdded()
)

[4] => SebastianBergmann\Diff\Line Object
(
[type:SebastianBergmann\Diff\Line:private] => 1
[content:SebastianBergmann\Diff\Line:private] => public function testAnotherMoneyObjectWithSameCurrencyCanBeAdded()
)

[5] => SebastianBergmann\Diff\Line Object
(
[type:SebastianBergmann\Diff\Line:private] => 3
[content:SebastianBergmann\Diff\Line:private] => {
)

[6] => SebastianBergmann\Diff\Line Object
(
[type:SebastianBergmann\Diff\Line:private] => 3
[content:SebastianBergmann\Diff\Line:private] => $a = new Money(1, new Currency('EUR'));
)

[7] => SebastianBergmann\Diff\Line Object
(
[type:SebastianBergmann\Diff\Line:private] => 3
[content:SebastianBergmann\Diff\Line:private] => $b = new Money(2, new Currency('EUR'));
)
)
)
)
)
)