baseline compare produces some false alarms

[mildm8nnered]

New Issue Checklist

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

Describe the bug

The baseline compare subcommand is implemented as follows:

    public func compare(_ otherBaseline: Baseline) -> [StyleViolation] {
        otherBaseline.baseline.flatMap {
            filter($1.violationsWithAbsolutePaths)
        }
    }

This re-uses the Baseline filter API, passing in the underlying StyleViolation's, and ignoring the existing text values. During filter, the files referred to in the StyleViolation will be read to determine the text for each StyleViolation. This is fine when linting, as the files will be present, but during baseline compare, there is no guarantee that the source files will be there at all, or that they will be the same as the files that were present when the baseline was constructed.

Where the files are not present, or have changed, the text values will not match, and violations for those files will be considered as "new" when comparing the baselines.

The fix for this will be to not throw away the text information in the Baseline, and to use a lower-level API to compare the baselines.

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

$ swiftlint.release  baseline compare --other-baseline 0.54.Baseline.json 0.53.Baseline.json --reporter summary
+-----------------------------------------+--------+-------------+--------+----------+--------+------------------+-----------------+
| rule identifier                         | opt-in | correctable | custom | warnings | errors | total violations | number of files |
+-----------------------------------------+--------+-------------+--------+----------+--------+------------------+-----------------+
| explicit_acl                            | yes    | no          | no     |      382 |      0 |              382 |             304 |
| explicit_top_level_acl                  | yes    | no          | no     |      288 |      0 |              288 |             286 |
| required_deinit                         | yes    | no          | no     |      228 |      0 |              228 |             176 |
| explicit_type_interface                 | yes    | no          | no     |      183 |      0 |              183 |              80 |
| indentation_width                       | yes    | no          | no     |       62 |      0 |               62 |              41 |
| no_extension_access_modifier            | yes    | no          | no     |        0 |     47 |               47 |              38 |
| file_types_order                        | yes    | no          | no     |       46 |      0 |               46 |              40 |
| type_contents_order                     | yes    | no          | no     |       41 |      0 |               41 |              19 |
| no_grouping_extension                   | yes    | no          | no     |       34 |      0 |               34 |              34 |
| prefer_nimble                           | yes    | no          | no     |       23 |      0 |               23 |               5 |
| one_declaration_per_file                | yes    | no          | no     |       17 |      0 |               17 |              15 |
| multiline_parameters_brackets           | yes    | no          | no     |       16 |      0 |               16 |               7 |
| missing_docs                            | yes    | no          | no     |       12 |      0 |               12 |               8 |
| no_magic_numbers                        | yes    | no          | no     |        9 |      0 |                9 |               8 |
| implicit_return                         | yes    | yes         | no     |        7 |      0 |                7 |               6 |
| superfluous_disable_command             | no     | no          | no     |        6 |      0 |                6 |               6 |
| superfluous_else                        | yes    | yes         | no     |        6 |      0 |                6 |               3 |
| multiline_arguments_brackets            | yes    | no          | no     |        5 |      0 |                5 |               2 |
| prefer_self_in_static_references        | yes    | yes         | no     |        5 |      0 |                5 |               3 |
| prefixed_toplevel_constant              | yes    | no          | no     |        5 |      0 |                5 |               5 |
| discouraged_optional_collection         | yes    | no          | no     |        4 |      0 |                4 |               3 |
| force_unwrapping                        | yes    | no          | no     |        4 |      0 |                4 |               2 |
| multiline_parameters                    | yes    | no          | no     |        4 |      0 |                4 |               4 |
| strict_fileprivate                      | yes    | no          | no     |        4 |      0 |                4 |               4 |
| trailing_closure                        | yes    | yes         | no     |        4 |      0 |                4 |               3 |
| vertical_whitespace_between_cases       | yes    | yes         | no     |        4 |      0 |                4 |               3 |
| anonymous_argument_in_multiline_closure | yes    | no          | no     |        3 |      0 |                3 |               1 |
| multiline_literal_brackets              | yes    | no          | no     |        3 |      0 |                3 |               3 |
| sorted_enum_cases                       | yes    | no          | no     |        2 |      0 |                2 |               1 |
| conditional_returns_on_newline          | yes    | no          | no     |        1 |      0 |                1 |               1 |
| function_default_parameter_at_end       | yes    | no          | no     |        1 |      0 |                1 |               1 |
| implicitly_unwrapped_optional           | yes    | no          | no     |        1 |      0 |                1 |               1 |
| let_var_whitespace                      | yes    | no          | no     |        1 |      0 |                1 |               1 |
| multiline_arguments                     | yes    | no          | no     |        1 |      0 |                1 |               1 |
| opening_brace                           | no     | yes         | no     |        1 |      0 |                1 |               1 |
+-----------------------------------------+--------+-------------+--------+----------+--------+------------------+-----------------+
| Total                                   |        |             |        |    1,413 |     47 |            1,460 |             348 |
+-----------------------------------------+--------+-------------+--------+----------+--------+------------------+-----------------+

Environment

• SwiftLint version (run swiftlint version to be sure)? 0.55.1
• Installation method used (Homebrew, CocoaPods, building from source, etc)? Cocoapods
• Paste your configuration file:

N/A

• Are you using nested configurations?
  If so, paste their relative paths and respective contents. No
• Which Xcode version are you using (check xcodebuild -version)? Xcode 15.2
• Do you have a sample that shows the issue? No