Regex for custom rule not matching (works in xcode search, not from linting)

[bryantv]

New Issue Checklist

• Updated SwiftLint to the latest version
• I searched for existing GitHub issues

Bug Report

Complete output when running SwiftLint, including the stack trace and command used

I've created regex to determine if a class has an empty line following it. When searching in xcode, this works perfectly. However, swiftlint does not seem to work properly.

Environment

• SwiftLint version 0.24.2
• Installation method used CocoaPods
• Paste your configuration file:

#disabled_rules: # rule identifiers to exclude from running
#opt_in_rules: # some rules are only opt-in
whitelist_rules:
  - class_delegate_protocol
  - closing_brace
  - closure_end_indentation
  - closure_parameter_position #debatable
  - comma
  - colon
  - control_statement
  - custom_rules
  - empty_count #error by default
  - empty_parameters
  #- empty_parentheses_with_trailing_closure # debatable
  - explicit_init # debatable
  - file_length
  - identifier_name # can't use because of _variable standard.  https://stackoverflow.com/questions/32192828/name-convention-for-unwrapped-value-in-swift
  - line_length
  - large_tuple
  - leading_whitespace
  - legacy_constant
  - literal_expression_end_indentation
  - mark
  - multiline_arguments
  - multiline_parameters
  # - multiple_closures_with_trailing_closure
  - opening_brace #debatable
  - operator_usage_whitespace
  - protocol_property_accessors_order
  - redundant_discardable_let
  - redundant_optional_initialization
  - redundant_string_enum_value
  - redundant_void_return
  - return_arrow_whitespace
  - shorthand_operator
  - statement_position
  - superfluous_disable_command	# not sure
  - switch_case_alignment
  - syntactic_sugar
  - trailing_newline
  - trailing_semicolon
  - type_body_length
  - type_name
  - unneeded_break_in_switch
  - vertical_parameter_alignment # dateable
  - vertical_parameter_alignment_on_call # debateble
  - vertical_whitespace
  - weak_delegate

  # Find all the available rules by running:
  # swiftlint rules
included: # paths to include during linting. `--path` is ignored if present.
  - //omitted for privacy
excluded: # paths to ignore during linting. Takes precedence over `included`.
  - Carthage
  - Pods
  - Source/ExcludedFolder
  - Source/ExcludedFile.swift

# forced errors
class_delegate_protocol:
  severity: error
closure_parameter_position:
  severity: error
closure_end_indentation:
  severity: error
comma:
  severity: error
colon:
  severity: error
control_statement:
  severity: error
empty_parameters:
  severity: error
empty_parentheses_with_trailing_closure:
  severity: error
large_tuple:
  severity: error
leading_whitespace:
  severity: error
legacy_constant:
  severity: error
legacy_constructor:
  severity: error
literal_expression_end_indentation:
  severity: error
mark:
  severity: error
multiline_arguments:
  severity: error
multiline_parameters:
  severity: error
multiple_closures_with_trailing_closure:
  severity: error
opening_brace:
  severity: error
weak_delegate:
  severity: error
operator_usage_whitespace:
  severity: error
protocol_property_accessors_order:
  severity: error
redundant_discardable_let:
  severity: error
redundant_optional_initialization:
  severity: error
redundant_string_enum_value:
  severity: error
redundant_void_return:
  severity: error
return_arrow_whitespace:
  severity: error
shorthand_operator:
  severity: error
statement_position:
  severity: error
switch_case_alignment:
  severity: error
syntactic_sugar:
  severity: error
trailing_newline:
  severity: error
trailing_semicolon:
  severity: error
unneeded_break_in_switch:
  severity: error
vertical_parameter_alignment:
  severity: error
vertical_parameter_alignment_on_call:
  severity: error
vertical_whitespace:
  severity: error


# configurable rules can be customized from this configuration file
# binary rules can set their severity level
force_cast: warning # implicitly
force_try:
  severity: warning # explicitly
# rules that have both warning and error levels, can set just the warning level
# implicitly
line_length:
  warning: 500
  error: 500

# they can set both implicitly with an array
type_body_length:
  - 600 # warning
  - 600 # error
# or they can set both explicitly
file_length:
  warning: 500
  error: 1200
large_tuple:
  warning: 3
  error: 4
# naming rules can set warnings/errors for min_length and max_length
# additionally they can set excluded names
type_name:
  min_length: 4 # only warning
  max_length: # warning and error
    warning: 40
    error: 50
  excluded: iPhone # excluded via string
identifier_name:
  min_length: # only min_length
    error: 3 # only error
  excluded: # excluded via string array
    - id
    - URL
    - lhs
    - rhs
reporter: "xcode" # reporter type (xcode, json, csv, checkstyle, junit, html, emoji)


custom_rules:
  space_after_class:
    name: "No Space After Class"
    message: "Empty line required after class declarations"
    regex: '^(open|internal|private|public)*class\s(?!func).*\{$\n(?!^\s*$)'
    severity: error

• Which Xcode version are you using (check xcode-select -p)? 9.2
• Do you have a sample that shows the issue?

Example of search in xcode:

Example of linting (notice the blank line- this is not found by the same regex using ctrl+f):

[ornithocoder]

I believe the regex is loaded into SwiftLint as a String/NSString. You might have to escape the backslash character; try '^(open|internal|private|public)*class\\s(?!func).*\\{$\\n(?!^\\s*$)' instead.

[marcelofabri]

Can you provide a sample file? I've tried with this snippet and it triggered the violation:

class Test {
    let x: Int
}

[bryantv]

The negative case also triggers the violation, though. If you enter a blank line between the class declaration and the property declaration, it still catches it (also try searching in xcode; works properly there)

// Should error
class Test {
    let x: Int
}

// Should not error
class Test {

    let x: Int
}

[bryantv]

@ornithocoder thanks for the suggestion, though the rest of the regex wouldn't work if that was the case; it's extremely close to working, but it seems something is failing in checking for that next line.

[marcelofabri]

@bryantv I still only get one violation with that example 🤔

Can you try running swiftlint from the command line?

[bryantv]

@marcelofabri same results, it finds both the positive and negative case.

[bryantv]

@marcelofabri it sounds like it's working correctly for you? same config file/xcode version? I'm wondering if the logic is correct and I have an environmental issue...

[ornithocoder]

@bryantv you're right. I didn't realize it's defined using single quotation marks instead of double quotation marks. No need to escape the backslash character.

The logic seems right:

Maybe SwiftLint doesn't handle multiline regex?

[marcelofabri]

@bryantv This is the configuration file I'm using:

whitelist_rules:
  - custom_rules

custom_rules:
  space_after_class:
    name: "No Space After Class"
    message: "Empty line required after class declarations"
    regex: '^(open|internal|private|public)*class\s(?!func).*\{$\n(?!^\s*$)'
    severity: error

$ swiftlint lint --path file.swift
Loading configuration from '.swiftlint.yml'
Linting Swift files at path file.swift
Linting 'file.swift' (1/1)
<redacted>/file.swift:2:1: error: No Space After Class Violation: Empty line required after class declarations (space_after_class)
Done linting! Found 1 violation, 1 serious in 1 file.

I'm using Xcode 9.2.

[bryantv]

@marcelofabri That's actually an interesting idea; perhaps one of the other rules in interfering with mine somehow. I'll do some experimenting and report back.

[bryantv]

@marcelofabri Afraid using that exact config and linting yielded the same results - both cases fire. Could there be something related to project layout? spaces vs. tabs, anything else you can think of?

[ornithocoder]

Hi :-) I still believe it's given the multiline nature of the rule. For the examples below I created four files with different code combinations:

01_file.swift: Single test that should throw a violation

// Should error
class Test {
    let x: Int
}

Temp →  swiftlint lint --path 01_file.swift 
Loading configuration from '.swiftlint.yml'
Linting Swift files at path 01_file.swift
Linting '01_file.swift' (1/1)
01_file.swift:2:1: warning: No Space After Class Violation: Empty line required after class declarations (space_after_class)
Done linting! Found 1 violation, 0 serious in 1 file.

Results:

• Expected: Violation
• Got: Violation

02_file.swift: Single test that should not throw a violation

// Should not error
class Test {

    let x: Int
}

Temp →  swiftlint lint --path 02_file.swift 
Loading configuration from '.swiftlint.yml'
Linting Swift files at path 02_file.swift
Linting '02_file.swift' (1/1)
Done linting! Found 0 violations, 0 serious in 1 file.

Results:

• Expected: No violation
• Got: No violation

03_file.swift: Two classes where the first one should throw a violation

// Should error
class Test {
    let x: Int
}

// Should not error
class Test {

    let x: Int
}

Temp →  swiftlint lint --path 03_file.swift 
Loading configuration from '.swiftlint.yml'
Linting Swift files at path 03_file.swift
Linting '03_file.swift' (1/1)
03_file.swift:2:1: warning: No Space After Class Violation: Empty line required after class declarations (space_after_class)
Done linting! Found 1 violation, 0 serious in 1 file.

Results:

• Expected: Violation on first class
• Got: Violation on first class

04_file.swift: Two classes where the second one should throw a violation

// Should not error
class Test {

    let x: Int
}

// Should error
class Test {
    let x: Int
}

Temp →  swiftlint lint --path 04_file.swift 
Loading configuration from '.swiftlint.yml'
Linting Swift files at path 04_file.swift
Linting '04_file.swift' (1/1)
04_file.swift:2:1: warning: No Space After Class Violation: Empty line required after class declarations (space_after_class)
Done linting! Found 1 violation, 0 serious in 1 file.

Results:

• Expected: Violation on second class
• Got: Violation on first class

---

[jpsim]

Any reason to keep this open?

[marcelofabri]

Closing this due to lack of activity.