From e023f02587863201f6e27aa87df082b50469ba72 Mon Sep 17 00:00:00 2001
From: "John Paul E. Balandan, CPA"
 <51850998+paulbalandan@users.noreply.github.com>
Date: Thu, 9 Sep 2021 07:44:47 +0800
Subject: [PATCH] Document new coding style guide

* Document new coding style guide

* Update contributing/styleguide.md

Co-authored-by: MGatner <mgatner@icloud.com>

Co-authored-by: MGatner <mgatner@icloud.com>
---
 contributing/README.rst     |   2 +-
 contributing/styleguide.md  | 259 ++++++++++++++++++++++++++++
 contributing/styleguide.rst | 327 ------------------------------------
 3 files changed, 260 insertions(+), 328 deletions(-)
 create mode 100644 contributing/styleguide.md
 delete mode 100644 contributing/styleguide.rst

diff --git a/contributing/README.rst b/contributing/README.rst
index b5539f8a8a..0e73b9e5d7 100644
--- a/contributing/README.rst
+++ b/contributing/README.rst
@@ -8,7 +8,7 @@ Contributing to CodeIgniter
 - `Contribution CSS <./css.rst>`_
 - `Framework internals <./internals.rst>`_
 - `CodeIgniter documentation <./documentation.rst>`_
-- `PHP Style Guide <./styleguide.rst>`_
+- `CodeIgniter Coding Style Guide <./styleguide.md>`_
 - `Developer's Certificate of Origin <../DCO.txt>`_
 
 CodeIgniter is a community driven project and accepts contributions of code
diff --git a/contributing/styleguide.md b/contributing/styleguide.md
new file mode 100644
index 0000000000..d746e672d3
--- /dev/null
+++ b/contributing/styleguide.md
@@ -0,0 +1,259 @@
+# CodeIgniter Coding Style Guide
+
+This document declares a set of coding conventions and rules to be followed when contributing PHP code
+to the CodeIgniter project.
+
+**Note:**
+> While we would recommend it, there's no requirement that you follow these conventions and rules in your
+own projects. Usage is discretionary within your projects but strictly enforceable within the framework.
+
+We follow the [PSR-12: Extended Coding Style][psr12] plus a set of our own
+styling conventions.
+
+The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",
+"MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC 2119](http://tools.ietf.org/html/rfc2119).
+
+_Portions of the following rules are from and attributed to [PSR-12][psr12]. Even if we do not copy all the rules to this coding style guide explicitly, such uncopied rules SHALL still apply._
+
+[psr12]: https://www.php-fig.org/psr/psr-12/
+## Implementation
+
+Our team uses [PHP CS Fixer](https://github.com/FriendsOfPHP/PHP-CS-Fixer) to apply coding standard fixes automatically. If you would like to leverage these tools yourself visit the [Official CodeIgniter Coding Standard](https://github.com/CodeIgniter/coding-standard) repository for details.
+
+## General
+
+### Files
+
+- All PHP files MUST use the Unix LF (linefeed) line ending only.
+- All PHP files MUST end with a non-blank line, terminated with a single LF.
+- The closing `?>` tag MUST be omitted from files containing only PHP.
+
+### Lines
+
+- There MUST NOT be a hard limit on line length.
+- The soft limit on line length MUST be 120 characters.
+- Lines SHOULD NOT be longer than 80 characters; lines longer than that SHOULD be split into multiple subsequent lines of no more than 80 characters each.
+- There MUST NOT be trailing whitespace at the end of lines.
+- Blank lines MAY be added to improve readability and to indicate related blocks of code except where explicitly forbidden.
+- There MUST NOT be more than one statement per line.
+
+### Indenting
+
+- Code MUST use an indent of 4 spaces for each indent level, and MUST NOT use tabs for indenting.
+
+### Keywords and Types
+
+- All PHP reserved [keywords][1] and [types][2] MUST be in lower case.
+- Any new types and keywords added to future PHP versions MUST be in lower case.
+- Short form of type keywords MUST be used i.e. `bool` instead of `boolean`, `int` instead of `integer` etc.
+
+[1]: http://php.net/manual/en/reserved.keywords.php
+[2]: http://php.net/manual/en/reserved.other-reserved-words.php
+
+## Declare Statements, Namespace, and Import Statements
+
+The header of a PHP file may consist of a number of different blocks. If present, each of the blocks below
+MUST be separated by a single blank line, and MUST NOT contain a blank line. Each block MUST be in the order
+listed below, although blocks that are not relevant may be omitted.
+
+- Opening `<?php` tag.
+- File-level docblock.
+- One or more declare statements.
+- The namespace declaration of the file.
+- One or more class-based `use` import statements.
+- One or more function-based `use` import statements.
+- One or more constant-based `use` import statements.
+- The remainder of the code in the file.
+
+When a file contains a mix of HTML and PHP, any of the above sections may still be used. If so, they MUST be
+present at the top of the file, even if the remainder of the code consists of a closing PHP tag and then a
+mixture of HTML and PHP.
+
+When the opening `<?php` tag is on the first line of the file, it MUST be on its own line with no other
+statements unless it is a file containing markup outside of PHP opening and closing tags.
+
+Import statements MUST never begin with a leading backslash as they must always be fully qualified.
+
+## Classes, Properties, and Methods
+
+The term "class" refers to all classes, interfaces, and traits.
+
+- Any closing brace MUST NOT be followed by any comment or statement on the same line.
+- When instantiating a new class, parentheses MUST always be present even when there are no arguments passed to the constructor.
+
+### Extends and Implements
+
+- The `extends` and `implements` keywords MUST be declared on the same line as the class name.
+- Lists of `implements` and, in the case of interfaces, `extends` MAY be split across multiple lines,
+	where each subsequent line is indented once. When doing so, the first item in the list MUST be on
+	the next line, and there MUST be only one interface per line.
+
+- The opening brace for the class MUST go on its own line; the closing brace for the class MUST go on the next line after the body.
+- Opening braces MUST be on their own line and MUST NOT be preceded or followed by a blank line.
+- Closing braces MUST be on their own line and MUST NOT be preceded by a blank line.
+
+### Using traits
+
+- The `use` keyword used inside the classes to implement traits MUST be declared on the next line after the opening brace.
+- Each individual trait that is imported into a class MUST be included one-per-line and each inclusion MUST have its own use import statement.
+- When the class has nothing after the use import statement, the class closing brace MUST be on the next line after the use import statement.
+- Otherwise, it MUST have a blank line after the use import statement.
+- When using the insteadof and as operators they must be used as follows taking note of indentation, spacing, and new lines.
+
+### Properties and Constants
+
+- Visibility MUST be declared on all properties.
+- Visibility MUST be declared on all constants if your project PHP minimum version supports constant visibilities (PHP 7.1 or later).
+- The `var` keyword MUST NOT be used to declare a property.
+- here MUST NOT be more than one property declared per statement.
+- Property names MUST NOT be prefixed with a single underscore to indicate protected or private visibility. That is, an underscore prefix explicitly has no meaning.
+- There MUST be a space between type declaration and property name.
+
+### Methods and Functions
+
+- Visibility MUST be declared on all methods.
+- Method names MUST NOT be prefixed with a single underscore to indicate protected or private visibility. That is, an underscore prefix explicitly has no meaning.
+- Method and function names MUST NOT be declared with space after the method name. The opening brace MUST go on its own line, and the closing brace MUST go on the next line following the body. There MUST NOT be a space after the opening parenthesis, and there MUST NOT be a space before the closing parenthesis.
+
+### Method and Function Arguments
+
+- In the argument list, there MUST NOT be a space before each comma, and there MUST be one space after each comma.
+- Argument lists MAY be split across multiple lines, where each subsequent line is indented once. When doing so, the first item in the list MUST be on the next line, and there MUST be only one argument per line.
+- When the argument list is split across multiple lines, the closing parenthesis and opening brace MUST be placed together on their own line with one space between them.
+- When you have a return type declaration present, there MUST be one space after the colon followed by the type declaration. The colon and declaration MUST be on the same line as the argument list closing parenthesis with no spaces between the two characters.
+- In nullable type declarations, there MUST NOT be a space between the question mark and the type.
+- When using the reference operator & before an argument, there MUST NOT be a space after it.
+- There MUST NOT be a space between the variadic three dot operator and the argument name.
+- When combining both the reference operator and the variadic three dot operator, there MUST NOT be any space between the two of them.
+
+### `abstract`, `final`, and `static`
+
+- When present, the `abstract` and `final` declarations MUST precede the visibility declaration.
+- When present, the `static` declaration MUST come after the visibility declaration.
+
+### Method and Function Calls
+
+- When making a method or function call, there MUST NOT be a space between the method or function name
+and the opening parenthesis, there MUST NOT be a space after the opening parenthesis, and there MUST NOT be a
+space before the closing parenthesis. In the argument list, there MUST NOT be a space before each comma, and
+there MUST be one space after each comma.
+- Argument lists MAY be split across multiple lines, where each subsequent line is indented once. When doing
+so, the first item in the list MUST be on the next line, and there MUST be only one argument per line. A
+single argument being split across multiple lines (as might be the case with an anonymous function or array)
+does not constitute splitting the argument list itself.
+
+## Control Structures
+
+The general style rules for control structures are as follows:
+
+- There MUST be one space after the control structure keyword
+- There MUST NOT be a space after the opening parenthesis
+- There MUST NOT be a space before the closing parenthesis
+- There MUST be one space between the closing parenthesis and the opening brace
+- The structure body MUST be indented once
+- The body MUST be on the next line after the opening brace
+- The closing brace MUST be on the next line after the body
+
+The body of each structure MUST be enclosed by braces. This standardizes how the structures look and reduces the likelihood of introducing errors as new lines get added to the body.
+
+### `if`, `elseif`, `else`
+
+- The keyword `elseif` SHOULD be used instead of else if so that all control keywords look like single words.
+- Expressions in parentheses MAY be split across multiple lines, where each subsequent line is indented at
+least once. When doing so, the first condition MUST be on the next line. The closing parenthesis and opening
+brace MUST be placed together on their own line with one space between them. Boolean operators between
+conditions MUST always be at the beginning or at the end of the line, not a mix of both.
+
+### `switch`, `case`
+
+- There MUST be a comment such as `// no break` when fall-through is intentional in a non-empty case body.
+- Expressions in parentheses MAY be split across multiple lines, where each subsequent line is indented at
+least once. When doing so, the first condition MUST be on the next line. The closing parenthesis and opening
+brace MUST be placed together on their own line with one space between them. Boolean operators between
+conditions MUST always be at the beginning or at the end of the line, not a mix of both.
+
+### `while`, `do while`
+
+- Expressions in parentheses MAY be split across multiple lines, where each subsequent line is indented at
+least once. When doing so, the first condition MUST be on the next line. The closing parenthesis and opening
+brace MUST be placed together on their own line with one space between them. Boolean operators between
+conditions MUST always be at the beginning or at the end of the line, not a mix of both.
+
+## Operators
+
+- Style rules for operators are grouped by arity (the number of operands they take).
+- When space is permitted around an operator, multiple spaces MAY be used for readability purposes.
+- All operators not described here are left undefined.
+
+### Unary operators
+
+- The increment/decrement operators MUST NOT have any space between the operator and operand.
+- Type casting operators MUST NOT have any space within the parentheses.
+
+### Binary operators
+
+- All binary arithmetic, comparison, assignment, bitwise, logical, string, and type operators MUST be preceded and followed by at least one space.
+
+### Ternary operators
+
+- The conditional operator, also known simply as the ternary operator, MUST be preceded and followed by at least one space around both the `?` and `:` characters.
+- When the middle operand of the conditional operator is omitted, the operator MUST follow the same style rules as other binary comparison operators.
+
+**Note:**
+> All the preceding rules are quoted from PSR-12. You may visit its website to view the code block samples.
+
+## Custom Conventions
+
+### File Naming
+
+- Files containing PHP code SHOULD end with a ".php" extension.
+- Files containing templates SHOULD end with a ".tpl" extension.
+- Files containing classes, interfaces, or traits MUST have their base name exactly matching the name
+of the classes they declare.
+- Files declaring procedural functions SHOULD be written in snake_case format.
+
+### Naming of Structural Elements
+
+- Constants MUST be declared in UPPERCASE_SEPARATED_WITH_UNDERSCORES.
+- Class names MUST be declared in PascalCase.
+- Method and property names MUST be declared in camelCase.
+- Procedural functions MUST be in snake_case.
+- Abbreviations/acronyms/initialisms SHOULD be written in their own natural format.
+
+### Logical Operators
+
+- The negation operator `!` SHOULD have one space from its argument.
+```diff
+-!$result
++! $result
+```
+
+- Use parentheses to clarify potentially confusing logical expressions.
+
+### PHP Docblocks (PHPDoc)
+
+- There SHOULD be no useless PHPDoc annotations.
+```diff
+-/**
+- * @param string $data Data
+- * @return void
+- */
+  public function analyse(string $data): void {};
+```
+
+### PHPUnit Assertions
+
+- As much as possible, you SHOULD always use the strict version of assertions.
+```diff
+-$this->assertEquals(12, (int) $axis);
++$this->assertSame(12, (int) $axis);
+```
+
+- Use the dedicated assertion instead of using internal types.
+```diff
+-$this->assertSame(true, is_cli());
++$this->assertTrue(is_cli());
+
+-$this->assertTrue(array_key_exists('foo', $array));
++$this->assertArrayHasKey('foo', $array);
+```
diff --git a/contributing/styleguide.rst b/contributing/styleguide.rst
deleted file mode 100644
index a500d663fe..0000000000
--- a/contributing/styleguide.rst
+++ /dev/null
@@ -1,327 +0,0 @@
-######################
-PHP Coding Style Guide
-######################
-
-The following document declares a set of coding convention rules to be
-followed when contributing PHP code to the CodeIgniter project.
-
-Some of these rules, like naming conventions for example, *may* be
-incorporated into the framework's logic and therefore be functionally
-enforced (which would be separately documented), but while we would
-recommend it, there's no requirement that you follow these conventions in
-your own applications.
-
-The `PHP Interop Group <http://www.php-fig.org/>`_ has proposed a number of
-canonical recommendations for PHP code style. CodeIgniter is not a member of
-of PHP-FIG. We commend their efforts to unite the PHP community,
-but no not agree with all of their recommendations.
-
-PSR-2 is PHP-FIG's Coding Style Guide. We do not claim conformance with it,
-although there are a lot of similarities. The differences will be pointed out
-below.
-
-The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
-"SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this document are to
-be interpreted as described in `RFC 2119 <http://www.ietf.org/rfc/rfc2119.txt>`_.
-
-*Note: When used below, the term "class" refers to all kinds of classes,
-interfaces and traits.*
-
-*****
-Files
-*****
-
-Formatting
-==========
-
-- Files MUST use UTF-8 character set encoding without BOM.
-- Files MUST use UNIX line endings (LF: `\n`).
-- Files MUST end with a single empty line (i.e. LF: `\n`).
-
-Structure
-=========
-
-- A single file SHOULD NOT declare more than one class.
-  Examples where we feel that more than one class in a source file
-  is appropriate:
-
-    -   `system/Debug/CustomExceptions` contains a number of CodeIgniter
-        exceptions and errors, that we want to use for a consistent
-        experience across applications.
-        If we stick with the purist route, then each of the 13+/- custom
-        exceptions would require an additional file, which would have a
-        performance impact at times.
-    -   `system/HTTP/Response` provides a RedirectException, used with the
-        Response class.
-    -   `system/Router/Router` similarly provides a RedirectException, used with
-        the Router class.
-
-- Files SHOULD either declare symbols (i.e. classes, functions, constants)
-  or execute non-declarative logic, but SHOULD NOT do both.
-
-Naming
-======
-
-- File names MUST end with a ".php" name extension and MUST NOT have
-  multiple name extensions.
-- Files declaring classes, interfaces or traits MUST have names exactly matching
-  the classes that they declare (obviously excluding the ".php" name extension).
-- Files declaring functions SHOULD be named in *snake_case.php*.
-
-*************************************
-Whitespace, indentation and alignment
-*************************************
-
-- Best practice: indentation SHOULD use only tabs.
-- Best practice: alignment SHOULD use only spaces.
-- If using tabs for anything, you MUST set the tab spacing to 4.
-
-This will accommodate the widest range of developer environment options,
-while maintaining consistency of code appearance.
-
-Following the "best practice" above,
-the following code block would have a single tab at the beginning of
-each line containing braces, and two tabs at the beginning of the
-nested statements. No alignment is implied::
-
-    {
-        $first = 1;
-        $second = 2;
-        $third = 3;
-    }
-
-Following the "best practice" above,
-the following code block would use spaces to have the assignment
-operators line up with each other::
-
-    {
-        $first  = 1;
-        $second = 2;
-        $third  = 3;
-    }
-
-.. note:: Our indenting and alignment convention differs from PSR-2, which
-    **only** uses spaces for both indenting and alignment.
-
-- Unnecessary whitespace characters MUST NOT be present anywhere within a
-  script.
-
-  That includes trailing whitespace after a line of code, two or
-  more spaces used when only one is necessary (excluding alignment), as
-  well as any other whitespace usage that is not functionally required or
-  explicitly described in this document.
-
-.. note:: With conforming tab settings, alignment spacing should
-    be preserved in all development environments.
-    A pull request that deals only with tabs or spaces for alignment
-    will not be favorably considered.
-
-****
-Code
-****
-
-PHP tags
-========
-
-- Opening tags MUST only use the `<?php` and `<?=` forms.
-
-  - Scripts producing output SHOULD use the "short echo" `<?=` tag.
-  - Scripts declaring and/or using conditional logic SHOULD use the "long"
-    `<?php` tag.
-
-- Closing `?>` tags SHOULD NOT be used, unless the intention is to start
-  direct output.
-
-  - Scripts that don't produce output MUST NOT use the closing `?>` tag.
-
-Namespaces and classes
-======================
-
-- Class names and namespaces SHOULD be declared in `UpperCamelCase`,
-  also called `StudlyCaps`, unless
-  another form is *functionally* required.
-
-  - Abbreviations in namespaces, class names and method names SHOULD be
-    written in capital letters (e.g. PHP).
-
-- Class constants MUST be declared in `CAPITALS_SEPARATED_BY_UNDERSCORES`.
-- Class methods, property names and other variables MUST be declared in
-  `lowerCamelCase()`.
-- Class methods and properties MUST have visibility declarations (i.e.
-  `public`, `private` or `protected`).
-
-Methods
--------
-
-To maintain consistency between core classes, class properties MUST
-be private or protected, and the following public methods
-MUST be used for each such property "x"
-
-- `getX()` when the method returns returns a property value, or null if not set
-- `setX(value)` changes a property value, doesn't return anything, and can
-  throw exceptions
-- `hasX()` returns a boolean to if a property exists
-- `newX()` creates an instance of a/the component object and returns it,
-  and can throw exceptions
-- `isX()` returns true/false for boolean properties
-
-- Methods SHOULD use type hints and return type hints
-
-Procedural code
-===============
-
-- Function and variable names SHOULD be declared in `snake_case()` (all
-  lowercase letters, separated by underscores), unless another form is
-  *functionally* required.
-- Constants MUST be declared in `CAPITALS_SEPARATED_BY_UNDERSCORES`.
-
-Keywords
-========
-
-- All keywords MUST be written in lowercase letters. This includes "scalar"
-  types, but does NOT include core PHP classes such as `stdClass` or
-  `Exception`.
-- Adjacent keywords are separated by a single space character.
-- The keywords `require`, `require_once`, `include`, `include_once` MUST
-  be followed by a single space character and MUST NOT be followed by a
-  parenthesis anywhere within the declaration.
-- The `function` keyword MUST be immediately followed by either an opening
-  parenthesis or a single space and a function name.
-- Other keywords not explicitly mentioned in this section MUST be separated
-  by a single space character from any printable characters around them and
-  on the same line.
-
-Operators
-=========
-
-- The single dot concatenation, incrementing, decrementing, error
-  suppression operators and references MUST NOT be separated from their
-  subjects.
-- Other operators not explicitly mentioned in this section MUST be
-  separated by a single space character from any printable characters
-  around them and on the same line.
-- An operator MUST NOT be the last set of printable characters on a line.
-- An operator MAY be the first set of printable characters on a line.
-
-Logical Operators
-=================
-
--   Use the symbol versions (**||** and **&&**) of the logical operators
-    instead of the word versions (**OR** and **AND**).
-
-        -   This is consistent with other programming languages
-        -   It avoids the problem of the assignment operator (**=**) having
-            higher precedence::
-
-                $result = true && false; // $result is false, expected
-                $result = true AND false; // $result is true, evaluated as "($result = true) AND false"
-                $result = (true AND false); // $result is false
-
--   The logical negation operator MUST be separated from its argument by a
-    single space, as in **! $result** instead of **!$result**
--   If there is potential confusion with a logical expression, then use
-    parentheses for clarity, as shown above.
-
-Control Structures
-==================
-
--   Control structures, such as **if/else** statements, **for/foreach** statements, or
-    **while/do** statements, MUST use a brace-surrounded block for their body
-    segments.
-
-    Good control structure examples::
-
-        if ( $foo )
-        {
-            $bar += $baz;
-        }
-        else
-        {
-            $baz = 'bar';
-        }
-
-    Not-acceptable control structures::
-
-        if ( $foo ) $bar = $oneThing + $anotherThing + $yetAnotherThing + $evenMore;
-
-        if ( $foo ) $bar += $baz;
-        else $baz = 'bar';
-
-Docblocks
-=========
-
-We use phpDocumentor (phpdoc) to generate the API docs, for all of the source
-code inside the `system` folder.
-
-It wants to see a file summary docblock at the top of a PHP file,
-before any PHP statements, and then a docblock before each documentable
-component, namely any class/interface/trait, and all public and protected
-methods/functions/variables. The docblock for a method or function
-is expected to describe the parameters, return value, and any exceptions
-thrown.
-
-Deviations from the above are considered errors by phpdoc.
-
-An example::
-
-    <?php
-
-    namespace CodeIgniter\Fruit;
-
-    use CodeIgniter\Config\BaseConfig;
-
-    /**
-     * Base class for entities in the CodeIgniter\Fruit module.
-     */
-    abstract class BaseFruit
-    {
-      /**
-        * The group a fruit belongs to.
-        *
-        * @var string
-        */
-      protected $group;
-
-      /**
-        * Fruit constructor.
-        *
-        * @param BaseConfig       $config
-        */
-      public function __construct(BaseConfig $Config)
-      {
-              $this->group   = 'Unknown';
-      }
-
-      /**
-        * Model a fruit ripening over time.
-        *
-        * @param	array	$params
-        */
-      abstract public function ripen(array $params);
-    }
-
-Other
-=====
-
-- Argument separators (comma: `,`) MUST NOT be preceded by a whitespace
-  character and MUST be followed by a space character or a newline
-  (LF: `\n`).
-- Semi-colons (i.e. `;`) MUST NOT be preceded by a whitespace character
-  and MUST be followed by a newline (LF: `\n`).
-
-- Opening parentheses SHOULD NOT be followed by a space character.
-- Closing parentheses SHOULD NOT be preceded by a space character.
-
-- Opening square brackets SHOULD NOT be followed by a space character,
-  unless when using the "short array" declaration syntax.
-- Closing square brackets SHOULD NOT be preceded by a space character,
-  unless when using the "short array" declaration syntax.
-
-- A curly brace SHOULD be the only printable character on a line, unless:
-
-  - When declaring an anonymous function.
-  - Inside a "variable variable" (i.e. `${$foo}` or `${'foo'.$bar}`).
-  - Around a variable in a double-quoted string (i.e. `"Foo {$bar}"`).
-
-.. note:: Our control structures braces convention differs from PSR-2.
-    We use "Allman style" notation instead.