liancheng / scalafix-organize-imports

A CI-friendly Scalafix semantic rule for organizing imports

Version Matrix

OrganizeImports

1. Getting started

1.1. sbt

Please refer to the Scalafix documentation for how to install Scalafix and invoking it in your sbt build.

To try this rule in the sbt console without adding this rule to your sbt build:

sbt> scalafix dependency:OrganizeImports@com.github.liancheng:organize-imports:0.5.0

To include this rule in your sbt build:

ThisBuild / scalafixDependencies += "com.github.liancheng" %% "organize-imports" % "0.5.0"

1.2. Mill

You can also include this rule in your Mill build using mill-scalafix:

def scalafixIvyDeps = Agg(ivy"com.github.liancheng::organize-imports:0.5.0")

1.3. For IntelliJ Scala plugin users

OrganizeImports allows you to specify a preset style via the preset option. To make it easier to add OrganizeImports into existing Scala projects built using the IntelliJ Scala plugin, OrganizeImports provides a preset style compatible with the default configuration of the IntelliJ Scala import optimizer. Please check the INTELLIJ_2020_3 preset style for more details.

1.4. Source formatting tools

The OrganizeImports rule respects source-formatting tools like Scalafmt. If an import statement is already organized according to the configuration, its original source level format is preserved. Therefore, in an sbt project, if you run the following command sequence:

sbt> scalafixAll
...
sbt> scalafmtAll
...
sbt> scalafixAll --check
...

Assuming that the first two commands run successfully, the last scalafixAll --check command should not fail even if some import statements are reformatted by the scalafmtAll command.

However, you should make sure that the source-formatting tools you use do not rewrite import statements in ways that conflict with OrganizeImports. For example, when using Scalafmt together with OrganizeImports, the ExpandImportSelectors, SortImports, and AsciiSortImports rewriting rules should not be used.

2. Configuration

2.1. Default Configuration values

OrganizeImports {
  blankLines = Auto
  coalesceToWildcardImportThreshold = null
  expandRelative = false
  groupExplicitlyImportedImplicitsSeparately = false
  groupedImports = Explode
  groups = [
    "*"
    "re:(javax?|scala)\\."
  ]
  importSelectorsOrder = Ascii
  importsOrder = Ascii
  preset = DEFAULT
  removeUnused = true
}
⚠️

Please do NOT use the Scalafix built-in RemoveUnused.imports together with OrganizeImports to remove unused imports. You may end up with broken code! It is still safe to use RemoveUnused to remove unused private members or local definitions, though.

Scalafix rewrites source files by applying patches generated by invoked rules. Each rule generates a patch based on the original text of the source files. When two patches generated by different rules conflict with each other, Scalafix is not able to reconcile the conflicts, and may produce broken code. It is very likely to happen when RemoveUnused and OrganizeImports are used together, since both rules rewrite import statements.

By default, OrganizeImports already removes unused imports for you (see the removeUnused option). It locates unused imports via compilation diagnostics, which is exactly how RemoveUnused does it. This mechanism works well in most cases, unless there are new unused imports generated while organizing imports, which is possible when the expandRelative option is set to true. For now, the only reliable workaround for this edge case is to run Scalafix twice, once with OrganizeImports, and another with RemoveUnused.

2.2. blankLines

Available since v0.5.0-alpha.1.

Configures whether blank lines between adjacent import groups are automatically or manually inserted. This option is used together with the --- blank line markers.

2.2.1. Value type

Enum: Auto | Manual

Auto

A blank line is automatically inserted between adjacent import groups. All blank line markers (---) configured in the groups option are ignored.

Manual

A blank line is inserted at all the positions where blank line markers appear in the groups option.

The following two configurations are equivalent:

OrganizeImports {
  blankLines = Auto
  groups = [
    "re:javax?\\."
    "scala."
    "*"
  ]
}

OrganizeImports {
  blankLines = Manual
  groups = [
    "re:javax?\\."
    "---"
    "scala."
    "---"
    "*"
  ]
}

2.2.2. Default value

Auto

2.2.3. Examples

Auto

Configuration:

OrganizeImports {
  blankLines = Auto
  groups = [
    "re:javax?\\."
    "scala."
    "*"
  ]
}

Before:

import scala.collection.JavaConverters._
import java.time.Clock
import sun.misc.BASE64Encoder
import javax.annotation.Generated
import scala.concurrent.ExecutionContext

After:

import java.time.Clock
import javax.annotation.Generated

import scala.collection.JavaConverters._
import scala.concurrent.ExecutionContext

import sun.misc.BASE64Encoder
Manual

Configuration:

OrganizeImports {
  blankLines = Manual
  groups = [
    "re:javax?\\."
    "scala."
    "---"
    "*"
  ]
}

Before:

import scala.collection.JavaConverters._
import java.time.Clock
import sun.misc.BASE64Encoder
import javax.annotation.Generated
import scala.concurrent.ExecutionContext

After:

import java.time.Clock
import javax.annotation.Generated
import scala.collection.JavaConverters._
import scala.concurrent.ExecutionContext

import sun.misc.BASE64Encoder

2.3. coalesceToWildcardImportThreshold

When the number of imported names exceeds a certain threshold, coalesce them into a wildcard import. Renames and unimports are left untouched.

🚧

Having this feature in OrganizeImports is mostly for feature parity with the IntelliJ IDEA Scala import optimizer, but coalescing grouped import selectors into a wildcard import may introduce compilation errors!

Here is an example to illustrate the risk. The following snippet compiles successfully:

import scala.collection.immutable._
import scala.collection.mutable.{ArrayBuffer, Map, Set}

object Example {
  val m: Map[Int, Int] = ???
}

The type of Example.m above is not ambiguous because the mutable Map explicitly imported in the second import takes higher precedence than the immutable Map imported via wildcard in the first import.

However, if we coalesce the grouped imports in the second import statement into a wildcard, there will be a compilation error:

import scala.collection.immutable._
import scala.collection.mutable._

object Example {
  val m: Map[Int, Int] = ???
}

This is because the type of Example.m becomes ambiguous now since both the mutable and immutable Map are imported via a wildcard and have the same precedence.

2.3.1. Value type

Integer. Not setting it or setting it to null disables this feature.

2.3.2. Default value

null

2.3.3. Examples

Configuration:

OrganizeImports {
  groupedImports = Keep
  coalesceToWildcardImportThreshold = 3
}

Before:

import scala.collection.immutable.{Seq, Map, Vector, Set}
import scala.collection.immutable.{Seq, Map, Vector}
import scala.collection.immutable.{Seq, Map, Vector => Vec, Set, Stream}
import scala.collection.immutable.{Seq, Map, Vector => _, Set, Stream}

After:

import scala.collection.immutable._
import scala.collection.immutable.{Map, Seq, Vector}
import scala.collection.immutable.{Vector => Vec, _}
import scala.collection.immutable.{Vector => _, _}

2.4. expandRelative

Expand relative imports into fully-qualified one.

🚧

Expanding relative imports may introduce new unused imports. For instance, relative imports in the following snippet

import scala.util
import util.control
import control.NonFatal

are expanded into

import scala.util
import scala.util.control
import scala.util.control.NonFatal

If neither scala.util nor scala.util.control is referenced anywhere after the expansion, they become unused imports.

Unfortunately, these newly introduced unused imports cannot be removed by setting removeUnused to true. Please refer to the removeUnused option for more details.

2.4.1. Value type

Boolean

2.4.2. Default value

false

2.4.3. Examples

Configuration:

OrganizeImports {
  expandRelative = true
  groups = ["re:javax?\\.", "scala.", "*"]
}

Before:

import scala.util
import util.control
import control.NonFatal
import scala.collection.JavaConverters._
import java.time.Clock
import sun.misc.BASE64Encoder
import javax.annotation.Generated
import scala.concurrent.ExecutionContext

After:

import java.time.Clock
import javax.annotation.Generated

import scala.collection.JavaConverters._
import scala.concurrent.ExecutionContext
import scala.util
import scala.util.control
import scala.util.control.NonFatal

import sun.misc.BASE64Encoder

2.5. groupExplicitlyImportedImplicitsSeparately

This option provides a workaround to a subtle and rarely seen correctness issue related to explicitly imported implicit names.

The following snippet helps illustrate the problem:

package a

import c._
import b.i

object b { implicit def i: Int = 1 }
object c { implicit def i: Int = 2 }

object Imports {
  def f()(implicit i: Int) = println(1)
  def main() = f()
}

The above snippet compiles successfully and outputs 1, because the explicitly imported implicit value b.i overrides c.i, which is made available via a wildcard import. However, if we reorder the two imports into:

import b.i
import c._

The Scala compiler starts complaining:

error: could not find implicit value for parameter i: Int
  def main() = f()
                ^

This behavior could be due to a Scala compiler bug since the Scala language specification requires that explicitly imported names should have higher precedence than names made available via a wildcard.

Unfortunately, Scalafix is not able to surgically identify conflicting implicit values behind a wildcard import. In order to guarantee correctness in all cases, when the groupExplicitlyImportedImplicitsSeparately option is set to true, all explicitly imported implicit names are moved into the trailing order-preserving import group together with relative imports, if any (see the trailing order-preserving import group section for more details).

🚧
In general, order-sensitive imports are fragile, and can easily be broken by either human collaborators or tools (e.g., the IntelliJ IDEA Scala import optimizer does not handle this case correctly). They should be eliminated whenever possible. This option is mostly useful when you are dealing with a large trunk of legacy codebase, and you want to minimize manual intervention and guarantee correctness in all cases.

2.5.1. Value type

Boolean

2.5.2. Default value

false

Rationale

This option defaults to false due to the following reasons:

  1. Although setting it to true avoids the aforementioned correctness issue, the result is unintuitive and confusing for many users since it looks like the groups option is not respected.

    E.g., why my scala.concurrent.ExecutionContext.Implicits.global import is moved to a separate group even if I have a scala. group defined in the groups option?

  2. The concerned correctness issue is rarely seen in real life. When it really happens, it is usually a sign of bad coding style, and you may want to tweak your imports to eliminate the root cause.

2.5.3. Examples

Configuration:

OrganizeImports {
  groups = ["scala.", "*"]
  groupExplicitlyImportedImplicitsSeparately = true
}

Before:

import org.apache.spark.SparkContext
import org.apache.spark.RDD
import scala.collection.mutable.ArrayBuffer
import scala.collection.mutable.Buffer
import scala.concurrent.ExecutionContext.Implicits.global
import scala.sys.process.stringToProcess

After:

import scala.collection.mutable.ArrayBuffer
import scala.collection.mutable.Buffer

import org.apache.spark.RDD
import org.apache.spark.SparkContext

import scala.concurrent.ExecutionContext.Implicits.global
import scala.sys.process.stringToProcess

2.6. groupedImports

Configure how to handle grouped imports.

2.6.1. Value type

Enum: Explode | Merge | AggressiveMerge | Keep

Explode

Explode grouped imports into separate import statements.

Merge

Merge imports sharing the same prefix into a single grouped import statement.

💡

You may want to check the AggressiveMerge option for more concise results despite a relatively low risk of introducing compilation errors.

OrganizeImports does not support cases where one name is renamed to multiple aliases within the same source file when groupedImports is set to Merge. (The IntelliJ IDEA Scala import optimizer does not support this either.)

Scala allows a name to be renamed to multiple aliases within a single source file, which makes merging import statements tricky. For example:

import java.lang.{Double => JDouble}
import java.lang.{Double => JavaDouble}
import java.lang.Integer

The above three imports can be merged into:

import java.lang.{Double => JDouble}
import java.lang.{Double => JavaDouble, Integer}

but not:

import java.lang.{Double => JDouble, Double => JavaDouble, Integer}

because Scala disallow a name (in this case, Double) to appear in one import multiple times.

Here’s a more complicated example:

import p.{A => A1}
import p.{A => A2}
import p.{A => A3}

import p.{B => B1}
import p.{B => B2}

import p.{C => C1}
import p.{C => C2}
import p.{C => C3}
import p.{C => C4}

While merging these imports, we may want to "bin-pack" them to minimize the number of the result import statements:

import p.{A => A1, B => B1, C => C1}
import p.{A => A2, B => B2, C => C2}
import p.{A => A3, C3 => C3}
import p.{C => C4}

However, in reality, renaming aliasing a name multiple times in the same source file is rarely a practical need. Therefore, OrganizeImports does not support this when groupedImports is set to Merge to avoid the extra complexity.

AggressiveMerge

Similar to Merge, but merges imports more aggressively and produces more concise results, despite a relatively low risk of introducing compilation errors.

The OrganizeImports rule tries hard to guarantee correctness in all cases. This forces it to be more conservative when merging imports, and may sometimes produce suboptimal output. Here is a concrete example about correctness:

import scala.collection.immutable._
import scala.collection.mutable.Map
import scala.collection.mutable._

object Example {
  val m: Map[Int, Int] = ???
}

At a first glance, it seems feasible to simply drop the second import since mutable._ already covers mutble.Map. However, similar to the example illustrated in the section about the coalesceToWildcardImportThreshold option, the type of Example.m above is mutable.Map, because the mutable Map explicitly imported in the second import takes higher precedence than the immutable Map imported via wildcard in the first import. If we merge the last two imports naively, we’ll get:

import scala.collection.immutable._
import scala.collection.mutable._

This triggers in a compilation error, because both immutable.Map and mutable.Map are now imported via wildcards with the same precedence. This makes the type of Example.m ambiguous. The correct result should be:

import scala.collection.immutable._
import scala.collection.mutable.{Map, _}

On the other hand, the case discussed above is rarely seen in practice. A more commonly seen case is something like:

import scala.collection.mutable.Map
import scala.collection.mutable._

Instead of being conservative and produce a suboptimal output like:

import scala.collection.mutable.{Map, _}

setting groupedImports to AggressiveMerge produces

import scala.collection.mutable._
Keep

Leave grouped imports and imports sharing the same prefix untouched.

2.6.2. Default value

Explode

Rationale

Despite making the import section lengthier, exploding grouped imports into separate import statements is made the default behavior because it is more friendly to version control and less likely to create annoying merge conflicts caused by trivial import changes.

2.6.3. Examples

Explode

Configuration:

OrganizeImports.groupedImports = Explode

Before:

import scala.collection.mutable.{ArrayBuffer, Buffer, StringBuilder}

After:

import scala.collection.mutable.ArrayBuffer
import scala.collection.mutable.Buffer
import scala.collection.mutable.StringBuilder
Merge

Configuration:

OrganizeImports.groupedImports = Merge

Before:

import scala.collection.mutable.ArrayBuffer
import scala.collection.mutable.Buffer
import scala.collection.mutable.StringBuilder
import scala.collection.immutable.Set
import scala.collection.immutable._

After:

import scala.collection.mutable.{ArrayBuffer, Buffer, StringBuilder}
import scala.collection.immutable.{Set, _}
AggressiveMerge

Configuration:

OrganizeImports.groupedImports = AggressiveMerge

Before:

import scala.collection.mutable.ArrayBuffer
import scala.collection.mutable.Buffer
import scala.collection.mutable.StringBuilder
import scala.collection.immutable.Set
import scala.collection.immutable._

After:

import scala.collection.mutable.{ArrayBuffer, Buffer, StringBuilder}
import scala.collection.immutable._

2.7. groups

Defines import groups by prefix patterns. Only global imports are processed.

All the imports matching the same prefix pattern are gathered into the same group and sorted by the order defined by the importsOrder option.

🚧
Comments living between imports being processed will be removed.
💡

OrganizeImports tries to match the longest prefix while grouping imports. For instance, the following configuration groups scala.meta. and scala. imports into different two groups properly:

OrganizeImports.groups = [
  "re:javax?\\."
  "scala."
  "scala.meta."
  "*"
]

No matter how the groups option is configured, a special order-preserving import group may appear after all the configured import groups when:

  1. The expandRelative option is set to false and there are relative imports.

  2. The groupExplicitlyImportedImplicitsSeparately option is set to true and there are implicit names explicitly imported.

This special import group is necessary because the above two kinds of imports are order sensitive:

Relative imports

For instance, sorting the following imports in alphabetical order introduces compilation errors:

import scala.util
import util.control
import control.NonFatal
Explicitly imported implicit names

Please refer to the groupExplicitlyImportedImplicitsSeparately option for more details.

2.7.1. Value type

An ordered list of import prefix pattern strings. A prefix pattern can be one of the following:

A plain-text pattern

For instance, "scala." is a plain-text pattern that matches imports referring the scala package. Please note that the trailing dot is necessary, otherwise you may have scalafix and scala imports in the same group, which is not what you want in most cases.

A regular expression pattern

A regular expression pattern starts with re:. For instance, "re:javax?\\." is such a pattern that matches both the java and the javax packages. Please refer to the java.util.regex.Pattern Javadoc page for the regular expression syntax. Note that special characters like backslashes must be escaped.

The wildcard pattern

The wildcard pattern, "*", defines the wildcard group, which matches all fully-qualified imports not belonging to any other groups. It can be omitted when it’s the last group. So the following two configurations are equivalent:

OrganizeImports.groups = ["re:javax?\\.", "scala.", "*"]
OrganizeImports.groups = ["re:javax?\\.", "scala."]
A blank line marker

Available since v0.5.0-alpha.1.

A blank line marker, "---", defines a blank line between two adjacent import groups when blankLines is set to Manual. It is ignored when blankLines is Auto. Leading and trailing blank line markers are always ignored. Multiple consecutive blank line markers are treated as a single one. So the following three configurations are all equivalent:

OrganizeImports {
  blankLines = Manual
  groups = [
    "----"
    "re:javax?\\."
    "----"
    "scala."
    "----"
    "----"
    "*"
    "----"
  ]
}

OrganizeImports {
  blankLines = Manual
  groups = [
    "re:javax?\\."
    "---"
    "scala."
    "---"
    "*"
  ]
}

OrganizeImports {
  blankLines = Auto
  groups = [
    "re:javax?\\."
    "scala."
    "*"
  ]
}

2.7.2. Default value

[
  "*"
  "re:(javax?|scala)\\."
]
Rationale

This aligns with the default configuration of the IntelliJ Scala plugin version 2020.3.

2.7.3. Examples

Fully-qualified imports only

Configuration:

OrganizeImports.groups = ["re:javax?\\.", "scala.", "*"]

Before:

import scala.collection.JavaConverters._
import java.time.Clock
import sun.misc.BASE64Encoder
import javax.annotation.Generated
import scala.concurrent.ExecutionContext

After:

import java.time.Clock
import javax.annotation.Generated

import scala.collection.JavaConverters._
import scala.concurrent.ExecutionContext

import sun.misc.BASE64Encoder
With relative imports

Configuration:

OrganizeImports.groups = ["re:javax?\\.", "scala.", "*"]

Before:

import scala.util
import util.control
import control.NonFatal
import scala.collection.JavaConverters._
import java.time.Clock
import sun.misc.BASE64Encoder
import javax.annotation.Generated
import scala.concurrent.ExecutionContext

After:

import java.time.Clock
import javax.annotation.Generated

import scala.collection.JavaConverters._
import scala.concurrent.ExecutionContext
import scala.util

import sun.misc.BASE64Encoder

import util.control
import control.NonFatal
With relative imports and an explicitly imported implicit name

Configuration:

OrganizeImports {
  groups = ["re:javax?\\.", "scala.", "*"]
  groupExplicitlyImportedImplicitsSeparately = true
}

Before:

import scala.util
import util.control
import control.NonFatal
import scala.collection.JavaConverters._
import java.time.Clock
import sun.misc.BASE64Encoder
import javax.annotation.Generated
import scala.concurrent.ExecutionContext.Implicits.global

After:

import java.time.Clock
import javax.annotation.Generated

import scala.collection.JavaConverters._
import scala.util

import sun.misc.BASE64Encoder

import util.control
import control.NonFatal
import scala.concurrent.ExecutionContext.Implicits.global
Regular expression

Defining import groups using regular expressions can be quite flexible. For instance, the scala.meta package is not part of the Scala standard library, but the default groups defined in the OrganizeImports.groups option move imports from this package into the scala. group. The following example illustrates how to move them into the wildcard group using regular expression.

Configuration:

OrganizeImports.groups = [
  "re:javax?\\."
  "re:scala.(?!meta\\.)"
  "*"
]

Before:

import scala.collection.JavaConverters._
import java.time.Clock
import sun.misc.BASE64Encoder
import scala.meta.Tree
import javax.annotation.Generated
import scala.concurrent.ExecutionContext
import scala.meta.Import
import scala.meta.Pkg

After:

import java.time.Clock
import javax.annotation.Generated

import scala.collection.JavaConverters._
import scala.concurrent.ExecutionContext

import scala.meta.Import
import scala.meta.Pkg
import scala.meta.Tree
import sun.misc.BASE64Encoder
With manually configured blank lines

Configuration:

OrganizeImports {
  blankLines = Manual
  groups = [
    "*"
    "---"
    "re:javax?\\."
    "scala."
  ]
}

Before:

import scala.collection.JavaConverters._
import java.time.Clock
import sun.misc.BASE64Encoder
import javax.annotation.Generated
import scala.concurrent.ExecutionContext

After:

import sun.misc.BASE64Encoder

import java.time.Clock
import javax.annotation.Generated
import scala.collection.JavaConverters._
import scala.concurrent.ExecutionContext

2.8. importSelectorsOrder

Specifies the order of grouped import selectors within a single import expression.

2.8.1. Value type

Enum: Ascii | SymbolsFirst | Keep

Ascii

Sort import selectors by ASCII codes, equivalent to the AsciiSortImports rewriting rule in Scalafmt.

SymbolsFirst

Sort import selectors by the groups: symbols, lower-case, upper-case, equivalent to the SortImports rewriting rule in Scalafmt.

Keep

Keep the original order.

2.8.2. Default value

Ascii

2.8.3. Examples

Ascii

Configuration:

OrganizeImports {
  groupedImports = Keep
  importSelectorsOrder = Ascii
}

Before:

import foo.{~>, `symbol`, bar, Random}

After:

import foo.{Random, `symbol`, bar, ~>}
SymbolsFirst

Configuration:

OrganizeImports {
  groupedImports = Keep
  importSelectorsOrder = SymbolsFirst
}

Before:

import foo.{Random, `symbol`, bar, ~>}

After:

import foo.{~>, `symbol`, bar, Random}

2.9. importsOrder

Specifies the order of import statements within import groups defined by the OrganizeImports.groups option.

2.9.1. Value type

Enum: Ascii | SymbolsFirst | Keep

Ascii

Sort import statements by ASCII codes. This is the default sorting order that the IntelliJ IDEA Scala import optimizer picks ("lexicographically" option).

SymbolsFirst

Put wildcard imports and grouped imports with braces first, otherwise same as Ascii. This replicates IntelliJ IDEA Scala’s "scalastyle consistent" option.

Keep

Keep the original order.

2.9.2. Default value

Ascii

2.9.3. Examples

Ascii

Configuration:

OrganizeImports {
  groupedImports = Keep
  importsOrder = Ascii
}

Before:

import scala.concurrent._
import scala.concurrent.{Future, Promise}
import scala.concurrent.ExecutionContext.Implicits._
import scala.concurrent.duration

After:

import scala.concurrent.ExecutionContext.Implicits._
import scala.concurrent._
import scala.concurrent.duration
import scala.concurrent.{Promise, Future}
SymbolsFirst

Configuration:

OrganizeImports {
  groupedImports = Keep
  importsOrder = SymbolsFirst
}

Before:

import scala.concurrent.ExecutionContext.Implicits._
import scala.concurrent._
import scala.concurrent.duration
import scala.concurrent.{Promise, Future}

After:

import scala.concurrent._
import scala.concurrent.{Future, Promise}
import scala.concurrent.ExecutionContext.Implicits._
import scala.concurrent.duration

2.10. preset

Specify a preset style.

2.10.1. Value type

Enum: DEFAULT | INTELLIJ_2020_3

DEFAULT

An opinionated style recommended for new projects. The OrganizeImports rule tries its best to ensure correctness in all cases when possible. This default style aligns with this principal. In addition, by setting groupedImports to Explode, this style is also more friendly to version control and less likely to create annoying merge conflicts caused by trivial import changes.

OrganizeImports {
  blankLines = Auto
  coalesceToWildcardImportThreshold = null
  expandRelative = false
  groupExplicitlyImportedImplicitsSeparately = false
  groupedImports = Explode
  groups = [
    "*"
    "re:(javax?|scala)\\."
  ]
  importSelectorsOrder = Ascii
  importsOrder = Ascii
  preset = DEFAULT
  removeUnused = true
}
INTELLIJ_2020_3

A style that is compatible with the default configuration of the IntelliJ Scala 2020.3 import optimizer. It is mostly useful for adding OrganizeImports to existing projects developed using the IntelliJ Scala plugin. However, the configuration of this style may introduce subtle correctness issues (so does the default configuration of the IntelliJ Scala plugin). Please see the coalesceToWildcardImportThreshold option for more details.

OrganizeImports {
  blankLines = Auto
  coalesceToWildcardImportThreshold = 5
  expandRelative = false
  groupExplicitlyImportedImplicitsSeparately = false
  groupedImports = Merge
  groups = [
    "*"
    "re:(javax?|scala)\\."
  ]
  importSelectorsOrder = Ascii
  importsOrder = Ascii
  preset = INTELLIJ_2020_3
  removeUnused = true
}
📓

This preset style sets blankLines to Manual, so that you can fully customize where a blank line should appear by adding the blank line marker, "---", in the groups option manually. Please refer to the blank line marker for more details.

2.10.2. Default value

DEFAULT

2.11. removeUnused

Remove unused imports.

🚧

As mentioned in the Getting started section, the removeUnused option doesn’t play perfectly with the expandRelative option. Setting expandRelative to true might introduce new unused imports (see expandRelative). These newly introduced unused imports cannot be removed by setting removeUnused to true. This is because unused imports are identified using Scala compilation diagnostics information, and the compilation phase happens before Scalafix rules get applied.

2.11.1. Value type

Boolean

2.11.2. Default value

true

2.11.3. Examples

Configuration:

OrganizeImports {
  groups = ["javax?\\.", "scala.", "*"]
  removeUnused = true
}

Before:

import scala.collection.mutable.{Buffer, ArrayBuffer}
import java.time.Clock
import java.lang.{Long => JLong, Double => JDouble}

object RemoveUnused {
  val buffer: ArrayBuffer[Int] = ArrayBuffer.empty[Int]
  val long: JLong = JLong.parseLong("0")
}

After:

import java.lang.{Long => JLong}

import scala.collection.mutable.ArrayBuffer

object RemoveUnused {
  val buffer: ArrayBuffer[Int] = ArrayBuffer.empty[Int]
  val long: JLong = JLong.parseLong("0")
}