<?php
/**
* Warns about code that can never been executed.
*
* @author Greg Sherwood <gsherwood@squiz.net>
* @copyright 2006-2015 Squiz Pty Ltd (ABN 77 084 670 600)
* @license https://github.com/squizlabs/PHP_CodeSniffer/blob/master/licence.txt BSD Licence
*/
namespace PHP_CodeSniffer\Standards\Squiz\Sniffs\PHP;
use PHP_CodeSniffer\Files\File;
use PHP_CodeSniffer\Sniffs\Sniff;
use PHP_CodeSniffer\Util\Tokens;
class NonExecutableCodeSniff implements Sniff
{
/**
* Returns an array of tokens this test wants to listen for.
*
* @return array
*/
public function register()
{
return [
T_BREAK,
T_CONTINUE,
T_RETURN,
T_THROW,
T_EXIT,
T_GOTO,
];
}//end register()
/**
* Processes this test, when one of its tokens is encountered.
*
* @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
* @param int $stackPtr The position of the current token in
* the stack passed in $tokens.
*
* @return void
*/
public function process(File $phpcsFile, $stackPtr)
{
$tokens = $phpcsFile->getTokens();
// If this token is preceded with an "or", it only relates to one line
// and should be ignored. For example: fopen() or die().
$prev = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($stackPtr - 1), null, true);
if ($tokens[$prev]['code'] === T_LOGICAL_OR || $tokens[$prev]['code'] === T_BOOLEAN_OR) {
return;
}
// Check if this token is actually part of a one-line IF or ELSE statement.
for ($i = ($stackPtr - 1); $i > 0; $i--) {
if ($tokens[$i]['code'] === T_CLOSE_PARENTHESIS) {
$i = $tokens[$i]['parenthesis_opener'];
continue;
} else if (isset(Tokens::$emptyTokens[$tokens[$i]['code']]) === true) {
continue;
}
break;
}
if ($tokens[$i]['code'] === T_IF
|| $tokens[$i]['code'] === T_ELSE
|| $tokens[$i]['code'] === T_ELSEIF
) {
return;
}
if ($tokens[$stackPtr]['code'] === T_RETURN) {
$next = $phpcsFile->findNext(T_WHITESPACE, ($stackPtr + 1), null, true);
if ($tokens[$next]['code'] === T_SEMICOLON) {
$next = $phpcsFile->findNext(T_WHITESPACE, ($next + 1), null, true);
if ($tokens[$next]['code'] === T_CLOSE_CURLY_BRACKET) {
// If this is the closing brace of a function
// then this return statement doesn't return anything
// and is not required anyway.
$owner = $tokens[$next]['scope_condition'];
if ($tokens[$owner]['code'] === T_FUNCTION) {
$warning = 'Empty return statement not required here';
$phpcsFile->addWarning($warning, $stackPtr, 'ReturnNotRequired');
return;
}
}
}
}
if (isset($tokens[$stackPtr]['scope_opener']) === true) {
$owner = $tokens[$stackPtr]['scope_condition'];
if ($tokens[$owner]['code'] === T_CASE || $tokens[$owner]['code'] === T_DEFAULT) {
// This token closes the scope of a CASE or DEFAULT statement
// so any code between this statement and the next CASE, DEFAULT or
// end of SWITCH token will not be executable.
$end = $phpcsFile->findEndOfStatement($stackPtr);
$next = $phpcsFile->findNext(
[
T_CASE,
T_DEFAULT,
T_CLOSE_CURLY_BRACKET,
T_ENDSWITCH,
],
($end + 1)
);
if ($next !== false) {
$lastLine = $tokens[$end]['line'];
for ($i = ($stackPtr + 1); $i < $next; $i++) {
if (isset(Tokens::$emptyTokens[$tokens[$i]['code']]) === true) {
continue;
}
$line = $tokens[$i]['line'];
if ($line > $lastLine) {
$type = substr($tokens[$stackPtr]['type'], 2);
$warning = 'Code after the %s statement on line %s cannot be executed';
$data = [
$type,
$tokens[$stackPtr]['line'],
];
$phpcsFile->addWarning($warning, $i, 'Unreachable', $data);
$lastLine = $line;
}
}
}//end if
// That's all we have to check for these types of statements.
return;
}//end if
}//end if
// This token may be part of an inline condition.
// If we find a closing parenthesis that belongs to a condition
// we should ignore this token.
$prev = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($stackPtr - 1), null, true);
if (isset($tokens[$prev]['parenthesis_owner']) === true) {
$owner = $tokens[$prev]['parenthesis_owner'];
$ignore = [
T_IF => true,
T_ELSE => true,
T_ELSEIF => true,
];
if (isset($ignore[$tokens[$owner]['code']]) === true) {
return;
}
}
$ourConditions = array_keys($tokens[$stackPtr]['conditions']);
if (empty($ourConditions) === false) {
$condition = array_pop($ourConditions);
if (isset($tokens[$condition]['scope_closer']) === false) {
return;
}
// Special case for BREAK statements sitting directly inside SWITCH
// statements. If we get to this point, we know the BREAK is not being
// used to close a CASE statement, so it is most likely non-executable
// code itself (as is the case when you put return; break; at the end of
// a case). So we need to ignore this token.
if ($tokens[$condition]['code'] === T_SWITCH
&& $tokens[$stackPtr]['code'] === T_BREAK
) {
return;
}
$closer = $tokens[$condition]['scope_closer'];
// If the closer for our condition is shared with other openers,
// we will need to throw errors from this token to the next
// shared opener (if there is one), not to the scope closer.
$nextOpener = null;
for ($i = ($stackPtr + 1); $i < $closer; $i++) {
if (isset($tokens[$i]['scope_closer']) === true) {
if ($tokens[$i]['scope_closer'] === $closer) {
// We found an opener that shares the same
// closing token as us.
$nextOpener = $i;
break;
}
}
}//end for
if ($nextOpener === null) {
$end = $closer;
} else {
$end = ($nextOpener - 1);
}
} else {
// This token is in the global scope.
if ($tokens[$stackPtr]['code'] === T_BREAK) {
return;
}
// Throw an error for all lines until the end of the file.
$end = ($phpcsFile->numTokens - 1);
}//end if
// Find the semicolon that ends this statement, skipping
// nested statements like FOR loops and closures.
for ($start = ($stackPtr + 1); $start < $phpcsFile->numTokens; $start++) {
if ($start === $end) {
break;
}
if ($tokens[$start]['code'] === T_OPEN_PARENTHESIS) {
$start = $tokens[$start]['parenthesis_closer'];
continue;
}
if ($tokens[$start]['code'] === T_OPEN_CURLY_BRACKET) {
$start = $tokens[$start]['bracket_closer'];
continue;
}
if ($tokens[$start]['code'] === T_SEMICOLON) {
break;
}
}//end for
if (isset($tokens[$start]) === false) {
return;
}
$lastLine = $tokens[$start]['line'];
for ($i = ($start + 1); $i < $end; $i++) {
if (isset(Tokens::$emptyTokens[$tokens[$i]['code']]) === true
|| isset(Tokens::$bracketTokens[$tokens[$i]['code']]) === true
|| $tokens[$i]['code'] === T_SEMICOLON
) {
continue;
}
// Skip whole functions and classes/interfaces because they are not
// technically executed code, but rather declarations that may be used.
if (isset(Tokens::$ooScopeTokens[$tokens[$i]['code']]) === true
|| $tokens[$i]['code'] === T_FUNCTION
|| $tokens[$i]['code'] === T_CLOSURE
) {
if (isset($tokens[$i]['scope_closer']) === false) {
// Parse error/Live coding.
return;
}
$i = $tokens[$i]['scope_closer'];
continue;
}
$line = $tokens[$i]['line'];
if ($line > $lastLine) {
$type = substr($tokens[$stackPtr]['type'], 2);
$warning = 'Code after the %s statement on line %s cannot be executed';
$data = [
$type,
$tokens[$stackPtr]['line'],
];
$phpcsFile->addWarning($warning, $i, 'Unreachable', $data);
$lastLine = $line;
}
}//end for
}//end process()
}//end class