Swiftlint Autocorrect Does Not Modify File

Question

In running swiftlint version 0.24.0, errors are reported. Running autocorrect states that the files have been corrected. Yet no modifications are made as a subsequent run of swiftlint proves.

See the attempt to lint and correct two files Player.swift and Prize.swift.

MacBook-Pro-5: Developer$ swiftlint 
Loading configuration from '.swiftlint.yml'
Linting Swift files in current working directory
Linting 'Prize.swift' (1/2)
Linting 'Player.swift' (2/2)
Player.swift:26:19: warning: Operator Function Whitespace Violation: Operators should be surrounded by a single whitespace when defining them. (operator_whitespace)
Player.swift:27: warning: Line Length Violation: Line should be 120 characters or less: currently 131 characters (line_length)
Player.swift:39: warning: Line Length Violation: Line should be 120 characters or less: currently 147 characters (line_length)
Prize.swift:44:34: warning: Colon Violation: Colons should be next to the identifier when specifying a type and next to the key in dictionary literals. (colon)
Prize.swift:44: error: Line Length Violation: Line should be 120 characters or less: currently 210 characters (line_length)
Done linting! Found 5 violations, 1 serious in 2 files.
MacBook-Pro-5: Developer$ swiftlint autocorrect
Loading configuration from '.swiftlint.yml'
Correcting Swift files in current working directory
Correcting 'Prize.swift' (1/2)
Correcting 'Player.swift' (2/2)
Done correcting 2 files!
MacBook-Pro-5: Developer$ swiftlint 
Loading configuration from '.swiftlint.yml'
Linting Swift files in current working directory
Linting 'Prize.swift' (1/2)
Linting 'Player.swift' (2/2)
Prize.swift:44:34: warning: Colon Violation: Colons should be next to the identifier when specifying a type and next to the key in dictionary literals. (colon)
Prize.swift:44: error: Line Length Violation: Line should be 120 characters or less: currently 210 characters (line_length)
Player.swift:26:19: warning: Operator Function Whitespace Violation: Operators should be surrounded by a single whitespace when defining them. (operator_whitespace)
Player.swift:27: warning: Line Length Violation: Line should be 120 characters or less: currently 131 characters (line_length)
Player.swift:39: warning: Line Length Violation: Line should be 120 characters or less: currently 147 characters (line_length)
Done linting! Found 5 violations, 1 serious in 2 files.
MacBook-Pro-5: Developer$

Here's another run but this time with one file Prize.swift containing only one correctable violation. Again, autocorrect does not modify:

MacBook-Pro-5:P Developer$ swiftlint 
Linting Swift files in current working directory
Linting 'Prize.swift' (1/2)
Linting 'Player.swift' (2/2)
PPrize.swift:44:34: warning: Colon Violation: Colons should be next to the identifier when specifying a type and next to the key in dictionary literals. (colon)
Done linting! Found 1 violation, 0 serious in 2 files.
MacBook-Pro-5:P Developer$ swiftlint autocorrect
Correcting Swift files in current working directory
Correcting 'Prize.swift' (1/2)
Correcting 'Player.swift' (2/2)
Done correcting 2 files!
MacBook-Pro-5:P Developer$ swiftlint 
Linting Swift files in current working directory
Linting 'Prize.swift' (1/2)
Linting 'Player.swift' (2/2)
PPrize.swift:44:34: warning: Colon Violation: Colons should be next to the identifier when specifying a type and next to the key in dictionary literals. (colon)
Done linting! Found 1 violation, 0 serious in 2 files.
MacBook-Pro-5:P Developer$ 

Note that the presence or not of a .swiftlint.yml file had zero bearing on this.

Abbreviated - that is, only showing relevant rules - output from swiftlint rules is shown below. Note that of the three violations, colon is definitely correctable.

MacBook-Pro-5: Developer$ swiftlint rules
+------------------------------------------+--------+-------------+------------------------+-------------+---------------------------------------------------------------------------------------------------------------------------+
| identifier                               | opt-in | correctable | enabled in your config | kind        | configuration                                                                                                             |
+------------------------------------------+--------+-------------+------------------------+-------------+---------------------------------------------------------------------------------------------------------------------------+
| colon                                    | no     | yes         | yes                    | style       | warning, flexible_right_spacing: false, apply_to_dictionaries: true                                                       |
| line_length                              | no     | no          | yes                    | metrics     | warning: 120, error: 200, ignores urls: false, ignores function declarations: false, ignores comments: false              |
| operator_whitespace                      | no     | no          | yes                    | style       | warning                                                                                                                   |
+------------------------------------------+--------+-------------+------------------------+-------------+---------------------------------------------------------------------------------------------------------------------------+

Any thoughts on how swiftlint autocorrect can run successfully? Might there be some obvious configuration or parameter I am missing? I have consulted https://github.com/realm/SwiftLint to no avail.

Answer 1

updated
swiftlint autocorrect --format
swiftlint --fix --format
swiftlint lint --fix --format

will work for all. source: https://github.com/realm/SwiftLint/issues/3571

old
if swiftlint version below 0.42.0 then you can auto correct it using swiftlint autocorrect --format

but if its 0.43.0 or higher then you need to use swiftlint --fix

it will auto correct the white space, trailing space, initial formating, bracket in if else. etc. which will not affect on your logics or codes.

swiftlint autocorrect --format //for version < 0.42.0
swiftlint --fix //for latest version >= 0.43.0

Answer 2

Not all SwiftLint rules are correctable, which mean that they will remain after you run swiftlint autocorrect. If you run swiftlint rules you can see a table that – among other things – show which rules are correctable.

I'm not sure what version of SwiftLint you are using, but I don't think line_length or operator_whitespace are correctable. You will have to deal with those yourself.