Drop support for ktlint-enable / ktlint-disable directive

[paul-dingemans]

The directives below can be used to suppress ktlint rules:

val foo = "foo" // ktlint-disable

/* ktlint-disable */
val foo = "foo"
/* ktlint-enable */

The usage of Suppress and SuppressWarning annotation however is more native and should be the only way starting from 1.0 version:

@Suppress("ktlint")
val foo = "foo"

Ideally, a rule is added which helps in autocorrecting the old directives to annotations. If this is implemented, take care that this rule itself should not be suppressed even in case for a line, block or file all annotations are suppressed.

[paul-dingemans]

Using Github Code Search some insight can be collected in how the old directives are used. Unfortunately, the total number of search result is currently limited to 100 results. By excluding based on repository, some more insights can be collected but this is also limited. In summer 2023 a new search API is expected which should be able to return all search results.

Insights sofar:

If a single construct is surrounded by a block directive, it should be replaced by an annotation on that single construct:

        /* ktlint-disable max-line-length */
        private const val URI_REGEX = "^(?:(?![^:@]+:[^:@/]*@)([^:/?#.]+):)?(?://)?((?:(([^:@]*)(?::([^:@]*))?)?@)?([^:/?#]*)(?::(\\d*))?)(((/(?:[^?#](?![^?#/]*\\.[^?#/.]+(?:[?#]|$)))*/?)?([^?#/]*))(?:\\?([^#]*))?(?:#(.*))?)"

        /* ktlint-enable max-line-length */

However if the directive block contains multiple statements, it can not be simply replaced with a Suppress on the first (nor on all statements). Moving the Suppress to an outer construct is not always equivalent to current situation:

    @Test
    fun testParseStringForHybridFileParcelable() {
        /* ktlint-disable max-line-length */
        // ls
        val lsLines = arrayOf(
            "-rwxr-x---   1 root   shell    29431 2009-01-01 08:00 init.rc",
            "lrw-r--r--   1 root   root        15 2009-01-01 08:00 product -> /system/product",
            "drwxr-xr-x  17 root   root      4096 1970-05-19 08:40 system",
            "-r--r--r-- 1 root root 10 1970-01-13 07:32 cpu_variant:arm",
            "lrwxrwxrwx  1 root root 0 2022-10-05 15:39 ac -> ../../devices/platform/GFSH0001:00/power_supply/ac",
            "lrwxrwxrwx   1 root root 0 2022-10-05 00:16 usb -> ../../devices/platform/soc/c440000.qcom,spmi/spmi-0/spmi0-02/c440000.qcom,spmi:qcom,pm8150b@2:qcom,qpnp-smb5/power_supply/usb"
        )

        // stat with old toybox or busybox
        // val a1 = "-rwxr-x--- 1 shell root 512 2009-01-01 08:00:00.000000000 `init.rc'"
        // val b1 = "lrw-r--r-- 1 root root 512 2009-01-01 08:00:00.000000000 `product' -> `/system/product'"
        // val c1 = "drwxr-xr-x 17 root root 512 1970-05-19 08:40:27.269999949 `system'"

        // stat with new toybox
        val statLines = arrayOf(
            "-rwxr-x--- 1 shell root 512 1230796800 `init.rc'",
            "lrw-r--r-- 1 root root 512 1230796800 `product' -> `/system/product'",
            "drwxr-xr-x 17 root root 512 11922027 `system'",
            "-r--r--r-- 1 root root 512 1035141 `cpu_variant:arm'",
            "lrwxrwxrwx 1 root root 512 1664955558 /sys/class/power_supply/ac -> '../../devices/platform/GFSH0001:00/power_supply/ac'",
            "lrwxrwxrwx 1 root root 512 1664956626 /sys/class/power_supply/usb -> '../../devices/platform/soc/c440000.qcom,spmi/spmi-0/spmi0-02/c440000.qcom,spmi:qcom,pm8150b@2:qcom,qpnp-smb5/power_supply/usb'"
        )
        /* ktlint-enable max-line-length */

        ....
    }

In example below, the block directive should be replaced with a file-annotation or the annotation must be interpreted as being relevant for the entire import list (but what if the annotation is not placed just before the first import?):

/* ktlint-disable import-ordering */
import android.app.Notification

In case below, the same EOL directive is repeated multiple times, but not on all lines. Usage of the block directive would have been a better choice in this example. But this is similar to one of problems mentioned before:

  val result = CharArray(16)
  result[ 0] = HEX_DIGIT_CHARS[(this shr 60 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[ 1] = HEX_DIGIT_CHARS[(this shr 56 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[ 2] = HEX_DIGIT_CHARS[(this shr 52 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[ 3] = HEX_DIGIT_CHARS[(this shr 48 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[ 4] = HEX_DIGIT_CHARS[(this shr 44 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[ 5] = HEX_DIGIT_CHARS[(this shr 40 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[ 6] = HEX_DIGIT_CHARS[(this shr 36 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[ 7] = HEX_DIGIT_CHARS[(this shr 32 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[ 8] = HEX_DIGIT_CHARS[(this shr 28 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[ 9] = HEX_DIGIT_CHARS[(this shr 24 and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[10] = HEX_DIGIT_CHARS[(this shr 20 and 0xf).toInt()]
  result[11] = HEX_DIGIT_CHARS[(this shr 16 and 0xf).toInt()]
  result[12] = HEX_DIGIT_CHARS[(this shr 12 and 0xf).toInt()]
  result[13] = HEX_DIGIT_CHARS[(this shr 8  and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[14] = HEX_DIGIT_CHARS[(this shr 4  and 0xf).toInt()] // ktlint-disable no-multi-spaces
  result[15] = HEX_DIGIT_CHARS[(this        and 0xf).toInt()] // ktlint-disable no-multi-spaces

References to old experimental rule set should be replaced with standard:

        /* ktlint-disable experimental:argument-list-wrapping */
        fixture.getSut(replacements = mapOf(Replacement.FileInputStream.STRING))

In example below, the block directive should be replace with a file annotation:

/* ktlint-disable */
@file:Suppress("PackageName", "TopLevelName")