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7th Gear (v3.57.2) edition

Rule string_implicit_backslashes

Handles implicit backslashes in strings and heredocs. Depending on the chosen strategy, it can escape implicit backslashes to ease the understanding of which are special chars interpreted by PHP and which not (escape), or it can remove these additional backslashes if you find them superfluous (unescape). You can also leave them as-is using ignore strategy.

Description

In PHP double-quoted strings and heredocs some chars like n, $ or u have special meanings if preceded by a backslash (and some are special only if followed by other special chars), while a backslash preceding other chars are interpreted like a plain backslash. The precise list of those special chars is hard to remember and to identify quickly: this fixer escapes backslashes that do not start a special interpretation with the char after them. It is possible to fix also single-quoted strings: in this case there is no special chars apart from single-quote and backslash itself, so the fixer simply ensure that all backslashes are escaped. Both single and double backslashes are allowed in single-quoted strings, so the purpose in this context is mainly to have a uniformed way to have them written all over the codebase.

Configuration

double_quoted

Whether to escape backslashes in double-quoted strings.

Allowed values: 'escape', 'ignore' and 'unescape'

Default value: 'escape'

heredoc

Whether to escape backslashes in heredoc syntax.

Allowed values: 'escape', 'ignore' and 'unescape'

Default value: 'escape'

single_quoted

Whether to escape backslashes in single-quoted strings.

Allowed values: 'escape', 'ignore' and 'unescape'

Default value: 'unescape'

Examples

Example #1

Default configuration.

--- Original
+++ New
 <?php

 $singleQuoted = 'String with \" and My\Prefix\\';

-$doubleQuoted = "Interpret my \n but not my \a";
+$doubleQuoted = "Interpret my \n but not my \\a";

 $hereDoc = <<<HEREDOC
-Interpret my \100 but not my \999
+Interpret my \100 but not my \\999
 HEREDOC;

Example #2

With configuration: ['single_quoted' => 'escape'].

--- Original
+++ New
 <?php

-$singleQuoted = 'String with \" and My\Prefix\\';
+$singleQuoted = 'String with \\" and My\\Prefix\\';

-$doubleQuoted = "Interpret my \n but not my \a";
+$doubleQuoted = "Interpret my \n but not my \\a";

 $hereDoc = <<<HEREDOC
-Interpret my \100 but not my \999
+Interpret my \100 but not my \\999
 HEREDOC;

Example #3

With configuration: ['double_quoted' => 'unescape'].

--- Original
+++ New
 <?php

 $singleQuoted = 'String with \" and My\Prefix\\';

 $doubleQuoted = "Interpret my \n but not my \a";

 $hereDoc = <<<HEREDOC
-Interpret my \100 but not my \999
+Interpret my \100 but not my \\999
 HEREDOC;

Example #4

With configuration: ['heredoc' => 'unescape'].

--- Original
+++ New
 <?php

 $singleQuoted = 'String with \" and My\Prefix\\';

-$doubleQuoted = "Interpret my \n but not my \a";
+$doubleQuoted = "Interpret my \n but not my \\a";

 $hereDoc = <<<HEREDOC
 Interpret my \100 but not my \999
 HEREDOC;

Rule sets

The rule is part of the following rule set:

  • @PhpCsFixer with config:

    ['single_quoted' => 'ignore']

References

The test class defines officially supported behaviour. Each test case is a part of our backward compatibility promise.