rspec/rules/S836/php/rule.adoc
Egon Okerman d1417e82f8
Modify CWE and OWASP Top 10 links to follow standard link format (APPSEC-1134) (#3529)
* Fix all CWE references

* Fix all OWASP references

* Fix missing CWE prefixes
2024-01-15 17:15:56 +01:00

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== Why is this an issue?
In PHP it is not required to initialize variables before their usage. However, using uninitialized variables is considered bad practice and should be avoided because of the following reasons:
* The value and type of uninitialized variables depend on the context of their first usage. It is better to be explicit about those to avoid confusion.
* The interpreter raises a warning or a notice in many cases.
=== Noncompliant code example
[source,php]
----
<?php
function getText(array $lines): string {
foreach ($lines as $line) {
$text .= $line;
}
return $text;
}
----
=== Compliant solution
[source,php]
----
<?php
function getText(array $lines): string {
$text = "";
foreach ($lines as $line) {
$text .= $line;
}
return $text;
}
----
== Resources
* CWE - https://cwe.mitre.org/data/definitions/457[CWE-457 - Use of Uninitialized Variable]
ifdef::env-github,rspecator-view[]
'''
== Implementation Specification
(visible only on this page)
=== Message
Review the data-flow - use of uninitialized value.
'''
== Comments And Links
(visible only on this page)
include::../comments-and-links.adoc[]
endif::env-github,rspecator-view[]