Option to increase default diff context size of 3 - reopened

[mhsdesign]

Succession issue for closed #981

Phpunit uses diffs to make objects or json strings comparable.

--- Expected
+++ Actual
@@ @@
     'rangeInSource' => Parser\Source\Range Object (
         'start' => Parser\Source\Position Object (...)
         'end' => Parser\Source\Position Object (
-            'lineNumber' => 2
+            'lineNumber' => 3
             'columnNumber' => 0
         )
     )
@@ @@
         'rangeInSource' => Parser\Source\Range Object (
             'start' => Parser\Source\Position Object (...)
             'end' => Parser\Source\Position Object (
-                'lineNumber' => 2
+                'lineNumber' => 3
                 'columnNumber' => 0
             )
         )
@@ @@

Now if some value objects in a deep structure are not equal (imagine the positions in a big AST) its funny to find out in the above output where the problem lies.

This can be made easier with a higher context size (like diff: -u, -U NUM, --unified[=NUM]). By default this is set to 3 as shown in the above output.

Now phpunit uses in https://github.com/sebastianbergmann/phpunit/blob/main/src/Framework/Constraint/String/StringMatchesFormatDescription.php#L133 the hardcoded UnifiedDiffOutputBuilder which again has a hardcoded context size of 3 https://github.com/sebastianbergmann/diff/blob/main/src/Output/UnifiedDiffOutputBuilder.php#L38.

There is already a pr to make the hard coded context size of 3 adjustable in the UnifiedDiffOutputBuilder sebastianbergmann/diff#122 but the pr is stale because it was said users should prefer the StrictUnifiedDiffOutputBuilder which would support this feature too.

Anyway i dont know what the preferred solution should be, i can volunteer to make the changes but for now just an locally increased context size like 8 allowed me to debug the assertions:

--- Expected
+++ Actual
@@ @@
 Language\AST\Node\Module\ModuleNode Object (
     'rangeInSource' => Parser\Source\Range Object (
         'start' => Parser\Source\Position Object (...)
         'end' => Parser\Source\Position Object (
-            'lineNumber' => 2
+            'lineNumber' => 3
             'columnNumber' => 0
         )
     )
     'imports' => Language\AST\Node\Import\ImportNodes Object (...)
     'export' => Language\AST\Node\Export\ExportNode Object (
         'rangeInSource' => Parser\Source\Range Object (
             'start' => Parser\Source\Position Object (...)
             'end' => Parser\Source\Position Object (
-                'lineNumber' => 2
+                'lineNumber' => 3
                 'columnNumber' => 0
             )
         )
         'declaration' => Language\AST\Node\ComponentDeclaration\ComponentDeclarationNode Object (
             'rangeInSource' => Parser\Source\Range Object (
                 'start' => Parser\Source\Position Object (...)

Related issues for more readable output: #5846, #4918