assignment branch condition

Red Green Repeat Adventures of a Spec Driven Junkie

Understanding assignment branch condition.

Recently, I integrated Rubocop into my work flow and it’s been very humbling. I feel I’m a great coder with all the specs passing and doing a good job of refactoring, Rubocop always finds something wrong with my code.

I usually go back and make fixes based on Rubocop’s suggestions, but I keep running into the same few issues and solving them isn’t as easy as using: rubocop -a (which auto-corrects all the easy ones!)

The toughest offense for me so far: Assignment Branch Condition

This offense is harder to fix really make me think about my coding style in general. I want to learn more about this offense to help me understand. By understanding, my goals is to not make this offense so often and/or make it easier for me to fix in the future.

What is: ABC?

Rubocop message:

The default is 15 and the first pass of my code is always way past this, probably on average twice this value. So cleaning up my code to meet the default value really takes a lot of work.

From the documentation :

Really Understanding: ABC

Let’s understand what ABC is by checking out the definition of ABC :

Broken down:

• assignments (anything with = )
• branches (anything that jumps out of the current method)
• conditionals (anything that tests logic if , case , unary ? )

SO, to reduce the ABC value, reduce assignments (use less intermediate variables), fewer branches (calling other methods), and conditionals (if/else statements).

Computing ABC

The ABC value is not just a counting of them, but a square root of the sum of their squares. If any one of them getting too high will spike the ABC count.

The Rubocop default for ABC metric is 15. What does 15 really mean?

Well, doing the math, to get an ABC score of 15, a method would have:

• 8 assignments
• 8 conditionals

(Just working backwards from 15*15 => 225; 225/3 => 75; Math.sqrt(75) ~=> 8.66)

Now that I lay it out that way, an ABC value of 15 is very reasonable. Having eight of each for a method is just enough to do a lot of work in a method, but a value of 15 keeps the method from spiraling out of control in assignments, branches, or conditionals.

Whenever I encountered Rubocop’s ‘ABC is too high’ message, I was annoyed with ABC metric because I didn’t understand how it was computed and I couldn’t refactor efficiently to lower the ABC value quickly.

Now that I spent some effort into researching what Assignment Branch Condition really means, I feel better about creating or refactoring code that has a better ABC score.

DEV Community

Posted on Jun 26, 2020 • Updated on Aug 3, 2020 • Originally published at thedevpost.com

11 Most Asked Questions About RuboCop

RuboCop is a Ruby static code analyzer and code formatter which helps to track errors easily and fix minor code issues during the development process saving your time. It has many advantages and you can learn more about RuboCop on https://docs.rubocop.org/en/stable/ .

Today, we will be talking about the most asked questions about RuboCop.

1. How to check if record exists from controller in Rails

How to test if at least one record exists?

Option 1: Using .exists?

Option 2: Using .present? (or .blank? , the opposite of .present? )

Option 3: Variable assignment in the if statement

This option can be considered a code smell by some linters (RuboCop for example).

Option 3b: Variable assignment

You can also use .find_by_user_id(current_user.id) instead of .where(...).first

Best option:

• If you don’t use the Business object(s): Option 1
• If you need to use the Business object(s): Option 3

Alternative Answer:

In this case, you can use the exists? method provided by ActiveRecord:

2. How to ignore lines with comments?

There is a way to ignore cops on a per-line basis.

There is also a way to do it via the configuration file.

Run rubocop --auto-gen-config and it will generate a file that you can use to disable the offenses.

The command also gives a hint on what to do to load those options.

On a line per line basis, you can enable and disable the cops as well.

You can also do more than one rule at a time in your code.

By using an inline directive, the directive becomes valid only for that line, and it would look like this:

It’s possible to define regex patterns to automatically ignore certain lines in rubocop.yml , so you could choose to ignore all lines starting with a # character:

This could be improved so that “indented” comment lines (i.e. whitespace followed by a # character) is also ignored if that’s what you want.

Note that this doesn’t account for lines of code that end with a comment, though:

3. How to split Ruby regex over multiple lines?

You need to use the /x modifier, which enables free-spacing mode.

Like in this case:

Using %r with the x option is the preferred way to do this.

See this example from the GitHub ruby style guide

4. RuboCop: Line is too long ← How to Ignore?

You can disable a bunch of lines like this:

Or add this to your .rubocop.yml file to increase the max length:

Creating a .rubocop.yml file (keep an eye on the initial . in the filename) in the root of your project, you’ll have a bunch of options:

5. What is meant by ‘Assignment Branch Condition Size too high’ and how to fix it?

Assignment Branch Condition (ABC) size is a measurement of the size of a method. It is essentially determined by counting the number of A ssignments, B ranches, and C onditional statements.

To reduce the ABC score, you could move some of those assignments into before_action calls:

6. How to tell RuboCop to ignore a specific directory or file?

You can add the following to .rubocop.yml:

where the path is relative to .rubocop.yml

From rubocop/default.yml :

7. How to integrate RuboCop with Rake?

The simple answer is just adding this to your Rakefile:

As of version 0.10.0 RuboCop contains a custom rake task that you can use. Just put the following in your Rakefile

Make sure to use upper-case ‘R’ and ‘C’ or you will get a NameError.

8. How to silence RuboCop warning on Assignment Branch Condition?

This is the message for the Metrics/AbcSize cop.

# rubocop:disable Metrics/AbcSize

On your RuboCop config

9. How to disable frozen string literal comment checking?

Add the following to your .rubocop.yml :

10. How to pass &:key as an argument to map instead of a block with Ruby?

Pass &:key as an argument to map instead of a block.

11. How to fix "SublimeLinter-RuboCop not running even when enabled and RuboCop in the path"?

First, specify the right path for you ruby env in Packages/User/SublimeLinter.sublime-settings as this:

After that close sublime completely and reopen it.

In Conclusion

These are the most asked questions about the RuboCop. If you have any suggestions or any confusion, please comment below. If you need any help, we will be glad to help you.

We, at Truemark , provide services like web and mobile app development, digital marketing, and website development. So, if you need any help and want to work with us, please feel free to contact us.

Hope this article helped you.

Original Source: DevPostbyTruemark

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What is meant by 'Assignment Branch Condition Size too high' and how to fix it?

In my Rails app, I use Rubocop to check for problems. Today it gave me an error like this : Assignment Branch Condition size for show is too high . Here's my code :

What does this mean and how can I fix it?

• 13 A brief search uncovers [this](http://c2.com/cgi/wiki?AbcMetric). It's a `rubocop`'s formal way of saying "your method does too much". –  D-side Jun 19 '15 at 08:11
• Are all of the defined variables be used in the rendering? –  Antarr Byrd Jun 19 '15 at 15:20

Conditional branching: if, '?'

Sometimes, we need to perform different actions based on different conditions.

To do that, we can use the if statement and the conditional operator ? , that’s also called a “question mark” operator.

The “if” statement

The if(...) statement evaluates a condition in parentheses and, if the result is true , executes a block of code.

For example:

In the example above, the condition is a simple equality check ( year == 2015 ), but it can be much more complex.

If we want to execute more than one statement, we have to wrap our code block inside curly braces:

We recommend wrapping your code block with curly braces {} every time you use an if statement, even if there is only one statement to execute. Doing so improves readability.

Boolean conversion

The if (…) statement evaluates the expression in its parentheses and converts the result to a boolean.

Let’s recall the conversion rules from the chapter Type Conversions :

• A number 0 , an empty string "" , null , undefined , and NaN all become false . Because of that they are called “falsy” values.
• Other values become true , so they are called “truthy”.

So, the code under this condition would never execute:

…and inside this condition – it always will:

We can also pass a pre-evaluated boolean value to if , like this:

The “else” clause

The if statement may contain an optional else block. It executes when the condition is falsy.

Several conditions: “else if”

Sometimes, we’d like to test several variants of a condition. The else if clause lets us do that.

In the code above, JavaScript first checks year < 2015 . If that is falsy, it goes to the next condition year > 2015 . If that is also falsy, it shows the last alert .

There can be more else if blocks. The final else is optional.

Conditional operator ‘?’

Sometimes, we need to assign a variable depending on a condition.

For instance:

The so-called “conditional” or “question mark” operator lets us do that in a shorter and simpler way.

The operator is represented by a question mark ? . Sometimes it’s called “ternary”, because the operator has three operands. It is actually the one and only operator in JavaScript which has that many.

The syntax is:

The condition is evaluated: if it’s truthy then value1 is returned, otherwise – value2 .

Technically, we can omit the parentheses around age > 18 . The question mark operator has a low precedence, so it executes after the comparison > .

This example will do the same thing as the previous one:

But parentheses make the code more readable, so we recommend using them.

In the example above, you can avoid using the question mark operator because the comparison itself returns true/false :

Multiple ‘?’

A sequence of question mark operators ? can return a value that depends on more than one condition.

It may be difficult at first to grasp what’s going on. But after a closer look, we can see that it’s just an ordinary sequence of tests:

• The first question mark checks whether age < 3 .
• If true – it returns 'Hi, baby!' . Otherwise, it continues to the expression after the colon “:”, checking age < 18 .
• If that’s true – it returns 'Hello!' . Otherwise, it continues to the expression after the next colon “:”, checking age < 100 .
• If that’s true – it returns 'Greetings!' . Otherwise, it continues to the expression after the last colon “:”, returning 'What an unusual age!' .

Here’s how this looks using if..else :

Non-traditional use of ‘?’

Sometimes the question mark ? is used as a replacement for if :

Depending on the condition company == 'Netscape' , either the first or the second expression after the ? gets executed and shows an alert.

We don’t assign a result to a variable here. Instead, we execute different code depending on the condition.

It’s not recommended to use the question mark operator in this way.

The notation is shorter than the equivalent if statement, which appeals to some programmers. But it is less readable.

Here is the same code using if for comparison:

Our eyes scan the code vertically. Code blocks which span several lines are easier to understand than a long, horizontal instruction set.

The purpose of the question mark operator ? is to return one value or another depending on its condition. Please use it for exactly that. Use if when you need to execute different branches of code.

if (a string with zero)

Will alert be shown?

Yes, it will.

Any string except an empty one (and "0" is not empty) becomes true in the logical context.

We can run and check:

The name of JavaScript

Using the if..else construct, write the code which asks: ‘What is the “official” name of JavaScript?’

If the visitor enters “ECMAScript”, then output “Right!”, otherwise – output: “You don’t know? ECMAScript!”

Demo in new window

Show the sign

Using if..else , write the code which gets a number via prompt and then shows in alert :

• 1 , if the value is greater than zero,
• -1 , if less than zero,
• 0 , if equals zero.

In this task we assume that the input is always a number.

Rewrite 'if' into '?'

Rewrite this if using the conditional operator '?' :

Rewrite 'if..else' into '?'

Rewrite if..else using multiple ternary operators '?' .

For readability, it’s recommended to split the code into multiple lines.

• If you have suggestions what to improve - please submit a GitHub issue or a pull request instead of commenting.
• If you can't understand something in the article – please elaborate.
• To insert few words of code, use the <code> tag, for several lines – wrap them in <pre> tag, for more than 10 lines – use a sandbox ( plnkr , jsbin , codepen …)

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Fix Rubocop issues

The current .rubocop_todo.yml file is ignoring alot of problems. We should fix these problems and ideally the todo should be zero or close to it.