Order conditionally-compiled imports (#1077)

* Order conditionally-compiled imports

* Order conditional imports based on configuration and add nested test case

* Preserve comments at start of conditionally compiled block in OrderedImports

* Add includeConditionalImports docs to OrderedImports.swift

Author: a7medev

Documentation/Configuration.md

@@ -296,6 +296,19 @@ too long.
 
 **default:** `false`
 
+---
+
+### `orderedImports`
+**type:** object
+
+**description:** Configuration for the `OrderedImports` rule.
+
+- `includeConditionalImports` _(boolean)_: Determines whether imports within conditional compilation blocks (`#if`, `#elseif`, `#else`) should be ordered. When `true`, imports inside conditional blocks will be sorted and organized according to the same rules as top-level imports. When `false`, imports within conditional blocks are left in their original order.
+
+**default:** `{ "includeConditionalImports" : false }`
+
+---
+
 > TODO: Add support for enabling/disabling specific syntax transformations in
 > the pipeline.
 

Documentation/RuleDocumentation.md

@@ -411,6 +411,9 @@ The order of the import groups is 1) regular imports, 2) declaration imports, 3)
 imports, and 4) @testable imports. These groups are separated by a single blank line. Blank lines in
 between the import declarations are removed.
 
+By default, imports within conditional compilation blocks (`#if`, `#elseif`, `#else`) are not ordered.
+This behavior can be controlled via the `orderedImports.includeConditionalImports` configuration option.
+
 Lint: If an import appears anywhere other than the beginning of the file it resides in,
       not lexicographically ordered, or  not in the appropriate import group, a lint error is
       raised.

Sources/SwiftFormat/API/Configuration+Default.swift

@@ -43,5 +43,6 @@ extension Configuration {
     self.multiElementCollectionTrailingCommas = true
     self.reflowMultilineStringLiterals = .never
     self.indentBlankLines = false
+    self.orderedImports = OrderedImportsConfiguration()
   }
 }

Sources/SwiftFormat/API/Configuration.swift

@@ -48,6 +48,7 @@ public struct Configuration: Codable, Equatable {
     case multiElementCollectionTrailingCommas
     case reflowMultilineStringLiterals
     case indentBlankLines
+    case orderedImports
   }
 
   /// A dictionary containing the default enabled/disabled states of rules, keyed by the rules'
@@ -301,6 +302,9 @@ public struct Configuration: Codable, Equatable {
   /// If false (the default), the whitespace in blank lines will be removed entirely.
   public var indentBlankLines: Bool
 
+  /// Configuration for the `OrderedImports` rule.
+  public var orderedImports: OrderedImportsConfiguration
+
   /// Creates a new `Configuration` by loading it from a configuration file.
   public init(contentsOf url: URL) throws {
     let data = try Data(contentsOf: url)
@@ -443,6 +447,13 @@ public struct Configuration: Codable, Equatable {
       )
       ?? defaults.indentBlankLines
 
+    self.orderedImports =
+      try container.decodeIfPresent(
+        OrderedImportsConfiguration.self,
+        forKey: .orderedImports
+      )
+      ?? defaults.orderedImports
+
     // If the `rules` key is not present at all, default it to the built-in set
     // so that the behavior is the same as if the configuration had been
     // default-initialized. To get an empty rules dictionary, one can explicitly
@@ -481,6 +492,8 @@ public struct Configuration: Codable, Equatable {
     try container.encode(noAssignmentInExpressions, forKey: .noAssignmentInExpressions)
     try container.encode(multiElementCollectionTrailingCommas, forKey: .multiElementCollectionTrailingCommas)
     try container.encode(reflowMultilineStringLiterals, forKey: .reflowMultilineStringLiterals)
+    try container.encode(indentBlankLines, forKey: .indentBlankLines)
+    try container.encode(orderedImports, forKey: .orderedImports)
     try container.encode(rules, forKey: .rules)
   }
 
@@ -546,3 +559,11 @@ public struct NoAssignmentInExpressionsConfiguration: Codable, Equatable {
 
   public init() {}
 }
+
+/// Configuration for the `OrderedImports` rule.
+public struct OrderedImportsConfiguration: Codable, Equatable {
+  /// Determines whether imports within conditional compilation blocks should be ordered.
+  public var includeConditionalImports: Bool = false
+
+  public init() {}
+}

Sources/SwiftFormat/Rules/OrderedImports.swift

@@ -17,6 +17,9 @@ import SwiftSyntax
 /// imports, and 4) @testable imports. These groups are separated by a single blank line. Blank lines in
 /// between the import declarations are removed.
 ///
+/// By default, imports within conditional compilation blocks (`#if`, `#elseif`, `#else`) are not ordered.
+/// This behavior can be controlled via the `orderedImports.includeConditionalImports` configuration option.
+///
 /// Lint: If an import appears anywhere other than the beginning of the file it resides in,
 ///       not lexicographically ordered, or  not in the appropriate import group, a lint error is
 ///       raised.
@@ -26,7 +29,13 @@ import SwiftSyntax
 public final class OrderedImports: SyntaxFormatRule {
 
   public override func visit(_ node: SourceFileSyntax) -> SourceFileSyntax {
-    let lines = generateLines(codeBlockItemList: node.statements, context: context)
+    var newNode = node
+    newNode.statements = orderImports(in: node.statements)
+    return newNode
+  }
+
+  private func orderImports(in codeBlockItemList: CodeBlockItemListSyntax) -> CodeBlockItemListSyntax {
+    let lines = generateLines(codeBlockItemList: codeBlockItemList, context: context)
 
     // Stores the formatted and sorted lines that will be used to reconstruct the list of code block
     // items later.
@@ -47,6 +56,10 @@ public final class OrderedImports: SyntaxFormatRule {
       // Perform linting on the grouping of the imports.
       checkGrouping(linesSection)
 
+      if let firstLine = fileHeader.first, firstLine.type == .blankLine {
+        fileHeader.removeFirst()
+      }
+
       if let lastLine = fileHeader.last, lastLine.type == .blankLine {
         fileHeader.removeLast()
       }
@@ -118,6 +131,27 @@ public final class OrderedImports: SyntaxFormatRule {
         }
       }
 
+      if context.configuration.orderedImports.includeConditionalImports,
+        let syntaxNode = line.syntaxNode,
+        case .ifConfigCodeBlock(let ifConfigCodeBlock) = syntaxNode
+      {
+        var ifConfigDecl = ifConfigCodeBlock.item.cast(IfConfigDeclSyntax.self)
+
+        let newClauses = ifConfigDecl.clauses.map { clause in
+          guard case .statements(let codeBlockItemList) = clause.elements else {
+            return clause
+          }
+          var newClause = clause
+          var newCodeBlockItemList = orderImports(in: codeBlockItemList)
+          newCodeBlockItemList.leadingTrivia = .newline + newCodeBlockItemList.leadingTrivia
+          newClause.elements = .statements(newCodeBlockItemList)
+          return newClause
+        }
+
+        ifConfigDecl.clauses = IfConfigClauseListSyntax(newClauses)
+        line.syntaxNode = .ifConfigCodeBlock(CodeBlockItemSyntax(item: .decl(DeclSyntax(ifConfigDecl))))
+      }
+
       // Separate lines into different categories along with any associated comments.
       switch line.type {
       case .regularImport:
@@ -154,9 +188,7 @@ public final class OrderedImports: SyntaxFormatRule {
       formatAndAppend(linesSection: lines[lastSliceStartIndex..<lines.endIndex])
     }
 
-    var newNode = node
-    newNode.statements = CodeBlockItemListSyntax(convertToCodeBlockItems(lines: formattedLines))
-    return newNode
+    return CodeBlockItemListSyntax(convertToCodeBlockItems(lines: formattedLines))
   }
 
   /// Raise lint errors if the different import types appear in the wrong order, and if import
@@ -354,11 +386,16 @@ private func generateLines(
       var blockWithoutTrailingTrivia = block
       blockWithoutTrailingTrivia.trailingTrivia = []
       currentLine.syntaxNode = .importCodeBlock(blockWithoutTrailingTrivia, sortable: sortable)
+    } else if block.item.is(IfConfigDeclSyntax.self) {
+      if currentLine.syntaxNode != nil {
+        appendNewLine()
+      }
+      currentLine.syntaxNode = .ifConfigCodeBlock(block)
     } else {
       if let syntaxNode = currentLine.syntaxNode {
         // Multiple code blocks can be merged, as long as there isn't an import statement.
         switch syntaxNode {
-        case .importCodeBlock:
+        case .importCodeBlock, .ifConfigCodeBlock:
           appendNewLine()
           currentLine.syntaxNode = .nonImportCodeBlocks([block])
         case .nonImportCodeBlocks(let existingCodeBlocks):
@@ -400,6 +437,8 @@ private func convertToCodeBlockItems(lines: [Line]) -> [CodeBlockItemSyntax] {
       switch syntaxNode {
       case .importCodeBlock(let codeBlock, _):
         append(codeBlockItem: codeBlock)
+      case .ifConfigCodeBlock(let ifConfigCodeBlock):
+        append(codeBlockItem: ifConfigCodeBlock)
       case .nonImportCodeBlocks(let codeBlocks):
         codeBlocks.forEach(append(codeBlockItem:))
       }
@@ -458,6 +497,9 @@ private class Line {
     case nonImportCodeBlocks([CodeBlockItemSyntax])
     /// A single code block item whose content must be an import decl.
     case importCodeBlock(CodeBlockItemSyntax, sortable: Bool)
+    /// A single code block item whose content must be an if config decl.
+    /// This is used to sort conditional imports.
+    case ifConfigCodeBlock(CodeBlockItemSyntax)
   }
 
   /// Stores line comments. `syntaxNode` need not be defined, since a comment can exist by itself on
@@ -478,7 +520,7 @@ private class Line {
   var type: LineType {
     if let syntaxNode = syntaxNode {
       switch syntaxNode {
-      case .nonImportCodeBlocks:
+      case .nonImportCodeBlocks, .ifConfigCodeBlock:
         return .codeBlock
       case .importCodeBlock(let importCodeBlock, _):
         guard let importDecl = importCodeBlock.item.as(ImportDeclSyntax.self) else {
@@ -542,6 +584,8 @@ private class Line {
       return codeBlock.firstToken(viewMode: .sourceAccurate)
     case .nonImportCodeBlocks(let codeBlocks):
       return codeBlocks.first?.firstToken(viewMode: .sourceAccurate)
+    case .ifConfigCodeBlock(let codeBlock):
+      return codeBlock.firstToken(viewMode: .sourceAccurate)
     }
   }
 
@@ -592,6 +636,8 @@ extension Line: CustomStringConvertible {
         description += "\(codeBlocks.count) code blocks "
       case .importCodeBlock(_, let sortable):
         description += "\(sortable ? "sorted" : "unsorted") import \(importName) "
+      case .ifConfigCodeBlock:
+        description += "if config code block "
       }
     }