rspec/rules/S134/tsql/rule.adoc

== Why is this an issue?

Nested ``++IF...ELSE++``, ``++WHILE++`` and ``++TRY...CATCH++`` statements is a key ingredient for making what's known as "Spaghetti code".


Such code is hard to read, refactor and therefore maintain.

=== Noncompliant code example

With the default threshold of 4:

[source,sql]
----
IF @flag1 = 1 -- Compliant - depth = 1
  BEGIN
    IF @flag2 = 2 -- Compliant - depth = 2
      BEGIN
        WHILE @var1 > 0  -- Compliant - depth = 3
          BEGIN
            IF @flag3 = 3 -- Compliant - depth = 4, not exceeding the limit
              BEGIN
                IF @flag4 = 4 -- Noncompliant - depth = 5
                  BEGIN
                    IF @flag5 = 5 -- Depth = 6, exceeding the limit, but issues are only reported on depth = 5
                      BREAK
                  END
              END
            SET @var1 = @var1 - 1
          END
      END
  END
----

ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

include::../message.adoc[]

=== Parameters

.max
****
_Integer_

----
4
----

Maximum allowed control flow statement nesting depth.
****


include::../highlighting.adoc[]

'''
== Comments And Links
(visible only on this page)

=== on 7 Mar 2018, 18:58:40 Ann Campbell wrote:
\[~freddy.mallet] we haven't (yet) deprecated this rule in favor of Cognitive Complexity, but do we want to continue adding new implementations?

=== on 8 Mar 2018, 08:36:40 Freddy Mallet wrote:
I would say yes [~ann.campbell.2] because for me the best way to get a massive adoption of the Cognitive Complexity metric is by not forcing anyone to use it. This rule is a good example of a basic feature that any developer not knowing the cognitive complexity metric would expect from a rule engine. And I think that would be a mistake to generate a kind of friction at the adoption of the rule engine by forcing people to "buy" the Cognitive Complexity metric. But promoting the Cognitive Complexity rule/metric in the description of this rule can be a good idea.

include::../comments-and-links.adoc[]

endif::env-github,rspecator-view[]