GoLongFuncs

golongfuncs is a tool for searching "long" functions by various measures (and combinations of measures).

This tool can help you to answer questions line:

• What are the longest functions with total complexity more than x?
• What are the longest functions with complexity per line of code more than x?
• What are functions with the biggest number of nested blocks?
• What are functions with the biggest number of control flow statements?
• What are the longest functions with max block nesting more than n?
• What are the functions with the most variables defined?
• What are the functions with the most variables and assignments?
• etc.

In other words, it will help you filter long and complex functions from those that are just long.

Installation

go install  github.com/tkrajina/golongfuncs/...

Measures

This tool can calculate the following function "length" and "complexity" measures:

• lines: Number of lines without empty lines, lines ending blocks (containing only }), and comments,
• total_lines: Number of lines including empty lines and comments,
• len: Number of characters in the function (without comments and empty lines).
• total_len: Number of characters in the function (with comments and empty lines).
• comments: Number of comments. Multiline comments are counted once,
• comment_lines: Number of comment lines,
• complexity: Cyclomatic complexity (from gocyclo),
• max_nesting: Max nested blocks depth (note, struct initializations are not counted),
• total_nesting: Total nesting (in other words, if the code is formatted properly -- every indentation tab is counted once)
• in_params: The number of function input parameters
• out_params: The number of function output parameters
• variables: The number of variables in the scope of the function (without function arguments and function receivers)
• assignments: The number of assignments in the function (including variable declarations, :=, =, +=, -=...)
• control: The number of control flow statements (if, else, switch, case, default, select and defer)
• todos: The number "TODO" tags found in comments (including function body and the commend preceding the function). Tags are HACK, TODO, NOTE, FIXME, ASAP, ISSUE, BUG and WTF.

In addition to those, you can combine measures. For example:

• complexity/lines: Calculates average complexity per line of code.
• total_nesting/total_lines: Calculates average nesting (indentation) per line.
• comment_lines/total_lines: Calculates lines of functions per line.
• etc.

To calculate any of those measure for your Golang code:

$ golongfuncs +variable
$ golongfuncs +total_nesting
$ golongfuncs +lines
$ golongfuncs +lines,complexity
$ golongfuncs +lines,complexity,complexity/lines

Calling just golongfuncs (without arguments) is an alias for golongfuncs +lines.

Usage examples

$ golongfuncs [flags] +[types] [paths...]

Find longest functions:

$ golongfuncs <go_file>
$ golongfuncs <directory>
$ golongfuncs <directory>/...

If path is not specified, golongfuncs assumes it is ./....

Show multiple measures:

$ golongfuncs +lines
$ golongfuncs +lines,in_params
$ golongfuncs +lines,in_params,complexity/lines
$ golongfuncs +lines +in_params +complexity/lines

If multiple measures are specified, the results are sorted by the first column (in this example lines):

By default the result shows only the top 20 results. Change that with -top:

$ golongfuncs -top 50

By default, functions shorter than 10 lines are ignored. You can change that with -min-lines <n>.

The 100 most complex functions:

$ golongfuncs -top 100 +complexity ./...

The most complex functions longer than 50 lines:

$ golongfuncs -min-lines 50 +complexity ./...

Find long functions, but calculate also their complexity, avg complexity and avg nesting:

$ golongfuncs +lines,complexity,complexity/lines,total_nesting/total_lines .
      ExampleVeryLongfunction golongfuncs/runner_test.go:118:1       lines=305.0    complexity=1.0    complexity/lines=0.1    total_nesting/total_lines=1.0
   ExampleVeryComplexFunction golongfuncs/runner_test.go:10:1         lines=69.0   complexity=44.0    complexity/lines=0.6    total_nesting/total_lines=6.7
                   printStats main.go:54:1                            lines=21.0    complexity=9.0    complexity/lines=0.4    total_nesting/total_lines=2.5
                         main main.go:12:1                            lines=19.0    complexity=3.0    complexity/lines=0.2    total_nesting/total_lines=1.0
                    TestLines golongfuncs/runner_test.go:476:1        lines=15.0    complexity=2.0    complexity/lines=0.1    total_nesting/total_lines=0.9
                   NewVisitor golongfuncs/runner.go:94:1              lines=15.0    complexity=3.0    complexity/lines=0.2    total_nesting/total_lines=1.0
                          Get golongfuncs/models.go:34:1              lines=15.0    complexity=7.0    complexity/lines=0.5    total_nesting/total_lines=1.7
                  TestNesting golongfuncs/runner_test.go:438:1        lines=15.0    complexity=2.0    complexity/lines=0.1    total_nesting/total_lines=0.9

You can see that ExampleVeryLongfunction is long (305 lines), but average complexity is low (0.1) and avg nesting is 1.0. Avg nesting 1.0 means that there are no nested blocks in this function. If half the lines were in a nested block (for example a big if <expr> { ...code... } block of code) the avg nesting would be 1.5.

The ExampleVeryComplexFunction is shorter (69 lines) but with an average complexity (per line of code) of 0.6 and avg nesting 6.7 and that is probably a good hint that the function needs refactoring.

Find functions longer than 5 lines with avg nesting (per line of code) bigger than 5 and include total lines count and lines count:

$ golongfuncs +total_nesting/total_lines,total_lines,lines -threshold 5 .
        ExampleVeryComplexFunction golongfuncs/runner_test.go:10:1             total_nesting/total_lines=6.7  total_lines=108.0   lines=69.0

Find functions with longest average line length:

$ golongfuncs +len/lines ./...
$ golongfuncs +total_len/total_lines ./...

Tests and vendored files are ignored, use -include-tests and -include-vendor if you want to measure them.

Arbitrary files/directories can be ignored with -ignore "<regexp>". For example, if you want to ignore Golang files containing _generated.go: -ignore "^.*_generated.go$".

Functions can be ignored with -ignore-func "regexp".

License

This tool is licensed under the Apache License, Version 2.0