Add fix command-line to apply quickfixes and unit test

Co-authored-by: Parham Saremi <parhaamsaremi@gmail.com>
Co-authored-by: webwarrior-ws <reg@webwarrior.ws>

Author: 3 people

src/FSharpLint.Console/Program.fs

@@ -6,6 +6,8 @@ open System.IO
 open System.Reflection
 open FSharpLint.Framework
 open FSharpLint.Application
+open System.Linq
+open System.Text
 
 /// Output format the linter will use.
 type private OutputFormat =
@@ -19,18 +21,28 @@ type internal FileType =
     | File = 3
     | Source = 4
 
+type ExitCode = 
+    | Error = -1
+    | Success = 0
+    | NoSuchRuleName = 1
+    | NoSuggestedFix = 2
+
+let fileTypeHelp = "Input type the linter will run against. If this is not set, the file type will be inferred from the file extension."
+
 // Allowing underscores in union case names for proper Argu command line option formatting.
 // fsharplint:disable UnionCasesNames
 type private ToolArgs =
     | [<AltCommandLine("-f")>] Format of OutputFormat
     | [<CliPrefix(CliPrefix.None)>] Lint of ParseResults<LintArgs>
+    | [<CliPrefix(CliPrefix.None)>] Fix of ParseResults<FixArgs>
     | Version
 with
     interface IArgParserTemplate with
         member this.Usage =
             match this with
             | Format _ -> "Output format of the linter."
             | Lint _ -> "Runs FSharpLint against a file or a collection of files."
+            | Fix _ -> "Apply quickfixes for specified rule name or names (comma separated)."
             | Version -> "Prints current version."
 
 // TODO: investigate erroneous warning on this type definition
@@ -45,10 +57,24 @@ with
         member this.Usage =
             match this with
             | Target _ -> "Input to lint."
-            | File_Type _ -> "Input type the linter will run against. If this is not set, the file type will be inferred from the file extension."
+            | File_Type _ -> fileTypeHelp
             | Lint_Config _ -> "Path to the config for the lint."
 // fsharplint:enable UnionCasesNames
 
+// TODO: investigate erroneous warning on this type definition
+// fsharplint:disable UnionDefinitionIndentation
+and private FixArgs =
+    | [<MainCommand; Mandatory>] Fix_Target of ruleName:string * target:string
+    | Fix_File_Type of FileType
+// fsharplint:enable UnionDefinitionIndentation
+with
+    interface IArgParserTemplate with
+        member this.Usage =
+            match this with
+            | Fix_Target _ -> "Rule name to be applied with suggestedFix and input to lint."
+            | Fix_File_Type _ -> fileTypeHelp
+// fsharplint:enable UnionCasesNames
+
 let private parserProgress (output:Output.IOutput) = function
     | Starting file ->
         String.Format(Resources.GetString("ConsoleStartingFile"), file) |> output.WriteInfo
@@ -71,7 +97,7 @@ let internal inferFileType (target:string) =
         FileType.Source
 
 let private start (arguments:ParseResults<ToolArgs>) (toolsPath:Ionide.ProjInfo.Types.ToolsPath) =
-    let mutable exitCode = 0
+    let mutable exitCode = ExitCode.Success
 
     let output =
         match arguments.TryGetResult Format with
@@ -87,38 +113,69 @@ let private start (arguments:ParseResults<ToolArgs>) (toolsPath:Ionide.ProjInfo.
         $"Current version: {version}" |> output.WriteInfo
         Environment.Exit 0
 
-    let handleError (str:string) =
+    let handleError (status:ExitCode) (str:string) =
         output.WriteError str
-        exitCode <- -1
+        exitCode <- status
 
-    match arguments.GetSubCommand() with
-    | Lint lintArgs ->
+    let outputWarnings (warnings: List<Suggestion.LintWarning>) =
+        String.Format(Resources.GetString "ConsoleFinished", List.length warnings)
+            |> output.WriteInfo
+    
+    let handleLintResult = function
+        | LintResult.Success warnings ->
+            outputWarnings warnings
+            if List.isEmpty warnings |> not then 
+               exitCode <- ExitCode.Error
+        | LintResult.Failure failure -> handleError ExitCode.Error failure.Description
+    
+    let handleFixResult (ruleName: string) = function
+        | LintResult.Success warnings ->
+            Resources.GetString "ConsoleApplyingSuggestedFixFile" |> output.WriteInfo
+            let increment = 1
+            let noFixIncrement = 0
+            let countSuggestedFix = 
+                warnings
+                |> List.sumBy (fun (element: Suggestion.LintWarning) ->
+                    let sourceCode = File.ReadAllText element.FilePath
+                    if String.Equals(ruleName, element.RuleName, StringComparison.InvariantCultureIgnoreCase) then
+                        match element.Details.SuggestedFix with
+                        | Some lazySuggestedFix ->
+                            lazySuggestedFix.Force()
+                            |> Option.iter (fun suggestedFix ->
+                                let updatedSourceCode = 
+                                    let builder = StringBuilder(sourceCode.Length + suggestedFix.ToText.Length)
+                                    let firstPart = 
+                                        sourceCode.AsSpan(
+                                            0,
+                                            (ExpressionUtilities.findPos suggestedFix.FromRange.Start sourceCode).Value
+                                        )
+                                    let secondPart = 
+                                        sourceCode.AsSpan
+                                            (ExpressionUtilities.findPos suggestedFix.FromRange.End sourceCode).Value
+                                    builder
+                                        .Append(firstPart)
+                                        .Append(suggestedFix.ToText)
+                                        .Append(secondPart)
+                                        .ToString()
+                                File.WriteAllText(
+                                    element.FilePath,
+                                    updatedSourceCode,
+                                    Encoding.UTF8)
+                                )
+                            increment
+                        | None -> noFixIncrement
+                    else
+                        noFixIncrement)
+            outputWarnings warnings
 
-        let handleLintResult = function
-            | LintResult.Success(warnings) ->
-                String.Format(Resources.GetString("ConsoleFinished"), List.length warnings)
-                |> output.WriteInfo
-                if not (List.isEmpty warnings) then exitCode <- -1
-            | LintResult.Failure(failure) ->
-                handleError failure.Description
+            if countSuggestedFix > 0 then
+                exitCode <- ExitCode.Success
+            else
+                exitCode <- ExitCode.NoSuggestedFix
 
-        let lintConfig = lintArgs.TryGetResult Lint_Config
-
-        let configParam =
-            match lintConfig with
-            | Some configPath -> FromFile configPath
-            | None -> Default
-
-
-        let lintParams =
-            { CancellationToken = None
-              ReceivedWarning = Some output.WriteWarning
-              Configuration = configParam
-              ReportLinterProgress = Some (parserProgress output) }
-
-        let target = lintArgs.GetResult Target
-        let fileType = lintArgs.TryGetResult File_Type |> Option.defaultValue (inferFileType target)
+        | LintResult.Failure failure -> handleError ExitCode.Error failure.Description
 
+    let linting fileType lintParams target toolsPath shouldFix maybeRuleName =
         try
             let lintResult =
                 match fileType with
@@ -127,16 +184,70 @@ let private start (arguments:ParseResults<ToolArgs>) (toolsPath:Ionide.ProjInfo.
                 | FileType.Solution -> Lint.lintSolution lintParams target toolsPath
                 | FileType.Project
                 | _ -> Lint.lintProject lintParams target toolsPath
-            handleLintResult lintResult
+            if shouldFix then
+                match maybeRuleName with
+                | Some ruleName -> handleFixResult ruleName lintResult
+                | None -> exitCode <- ExitCode.NoSuchRuleName
+            else
+                handleLintResult lintResult
         with
         | e ->
             let target = if fileType = FileType.Source then "source" else target
-            $"Lint failed while analysing %s{target}.{Environment.NewLine}Failed with: %s{e.Message}{Environment.NewLine}Stack trace: {e.StackTrace}"
-            |> handleError
-    | _ -> ()
+            sprintf "Lint failed while analysing %s.\nFailed with: %s\nStack trace: %s" target e.Message e.StackTrace
+            |> (handleError ExitCode.Error)
+
+    let getParams config =
+        let paramConfig =
+            match config with
+            | Some configPath -> FromFile configPath
+            | None -> Default
+
+        { CancellationToken = None
+          ReceivedWarning = Some output.WriteWarning
+          Configuration = paramConfig
+          ReportLinterProgress = parserProgress output |> Some }
+
+    let applyLint (lintArgs: ParseResults<LintArgs>) =
+        let lintConfig = lintArgs.TryGetResult Lint_Config
 
-    exitCode
+        let lintParams = getParams lintConfig
+        let target = lintArgs.GetResult Target
+        let fileType = lintArgs.TryGetResult File_Type |> Option.defaultValue (inferFileType target)
+
+        linting fileType lintParams target toolsPath false None
+
+    let applySuggestedFix (fixArgs: ParseResults<FixArgs>) =
+        let fixParams = getParams None
+        let ruleName, target = fixArgs.GetResult Fix_Target
+        let fileType = fixArgs.TryGetResult Fix_File_Type |> Option.defaultValue (inferFileType target)
+        
+        let allRules = 
+            match getConfig fixParams.Configuration with
+            | Ok config -> Some (Configuration.flattenConfig config false)
+            | _ -> None
+
+        let allRuleNames =
+            match allRules with
+            | Some rules ->  (fun (loadedRules:Configuration.LoadedRules) -> ([|
+                loadedRules.LineRules.IndentationRule |> Option.map (fun rule -> rule.Name) |> Option.toArray
+                loadedRules.LineRules.NoTabCharactersRule |> Option.map (fun rule -> rule.Name) |> Option.toArray
+                loadedRules.LineRules.GenericLineRules |> Array.map (fun rule -> rule.Name)
+                loadedRules.AstNodeRules |> Array.map (fun rule -> rule.Name)
+                |] |> Array.concat |> Set.ofArray)) rules
+            | _ -> Set.empty
+
+        if allRuleNames.Any(fun aRuleName -> String.Equals(aRuleName, ruleName, StringComparison.InvariantCultureIgnoreCase)) then
+            linting fileType fixParams target toolsPath true (Some ruleName)
+        else
+            sprintf "Rule '%s' does not exist." ruleName |> (handleError ExitCode.NoSuchRuleName)
+
+    match arguments.GetSubCommand() with
+    | Lint lintArgs -> applyLint lintArgs
+    | Fix fixArgs -> applySuggestedFix fixArgs
+    | _ -> ()
 
+    int exitCode
+    
 /// Must be called only once per process.
 /// We're calling it globally so we can call main multiple times from our tests.
 let toolsPath = Ionide.ProjInfo.Init.init (DirectoryInfo <| Directory.GetCurrentDirectory())  None

src/FSharpLint.Core/Application/Configuration.fs

@@ -103,13 +103,20 @@ type RuleConfig<'Config> = {
 
 type EnabledConfig = RuleConfig<unit>
 
-let constructRuleIfEnabled rule ruleConfig = if ruleConfig.Enabled then Some rule else None
+let constructRuleIfEnabledBase (onlyEnabled: bool) rule ruleConfig = 
+    if not onlyEnabled || ruleConfig.Enabled then Some rule else None
 
-let constructRuleWithConfig rule ruleConfig =
-    if ruleConfig.Enabled then
-        ruleConfig.Config |> Option.map rule
-    else
-        None
+let constructRuleIfEnabled rule ruleConfig = 
+    constructRuleIfEnabledBase true rule ruleConfig
+
+let constructRuleWithConfigBase (onlyEnabled: bool) (rule: 'TRuleConfig -> 'TRule) (ruleConfig: RuleConfig<'TRuleConfig>): Option<'TRule> =
+     if not onlyEnabled || ruleConfig.Enabled then
+         ruleConfig.Config |> Option.map rule
+     else
+         None
+ 
+let constructRuleWithConfig (rule: 'TRuleConfig -> 'TRule) (ruleConfig: RuleConfig<'TRuleConfig>): Option<'TRule> =
+    constructRuleWithConfigBase true rule ruleConfig
 
 let constructTypePrefixingRuleWithConfig rule (ruleConfig: RuleConfig<TypePrefixing.Config>) =
     if ruleConfig.Enabled then
@@ -617,7 +624,7 @@ let private parseHints (hints:string []) =
     |> Array.toList
     |> MergeSyntaxTrees.mergeHints
 
-let flattenConfig (config:Configuration) =
+let flattenConfig (config:Configuration) (onlyEnabled:bool) =
     let deprecatedAllRules =
         [|
             config.formatting |> Option.map (fun config -> config.Flatten()) |> Option.toArray |> Array.concat
@@ -626,6 +633,12 @@ let flattenConfig (config:Configuration) =
             config.Hints |> Option.map (fun config -> HintMatcher.rule { HintMatcher.Config.HintTrie = parseHints (getOrEmptyList config.add) }) |> Option.toArray
         |] |> Array.concat
 
+    let constructRuleIfEnabled rule ruleConfig = 
+        constructRuleIfEnabledBase onlyEnabled rule ruleConfig
+
+    let constructRuleWithConfig (rule: 'TRuleConfig -> 'TRule) (ruleConfig: RuleConfig<'TRuleConfig>): Option<'TRule> =
+        constructRuleWithConfigBase onlyEnabled rule ruleConfig
+    
     let allRules =
         [|
             config.TypedItemSpacing |> Option.bind (constructRuleWithConfig TypedItemSpacing.rule)

src/FSharpLint.Core/Application/Lint.fs

@@ -207,7 +207,7 @@ module Lint =
             | Some(x) -> not x.IsCancellationRequested
             | None -> true
 
-        let enabledRules = Configuration.flattenConfig lintInfo.Configuration
+        let enabledRules = Configuration.flattenConfig lintInfo.Configuration true
 
         let lines = String.toLines fileInfo.Text |> Array.map (fun (line, _, _) -> line)
         let allRuleNames =
@@ -373,7 +373,7 @@ module Lint =
     }
 
     /// Gets a FSharpLint Configuration based on the provided ConfigurationParam.
-    let private getConfig (configParam:ConfigurationParam) =
+    let getConfig (configParam:ConfigurationParam) =
         match configParam with
         | Configuration config -> Ok config
         | FromFile filePath ->

src/FSharpLint.Core/Application/Lint.fsi

@@ -144,4 +144,6 @@ module Lint =
 
     /// Lints an F# file that has already been parsed using
     /// `FSharp.Compiler.Services` in the calling application.
-    val lintParsedFile : optionalParams:OptionalLintParameters -> parsedFileInfo:ParsedFileInformation -> filePath:string -> LintResult
+    val lintParsedFile : optionalParams:OptionalLintParameters -> parsedFileInfo:ParsedFileInformation -> filePath:string -> LintResult
+
+    val getConfig : ConfigurationParam -> Result<Configuration,string>

src/FSharpLint.Core/Text.resx

@@ -138,6 +138,9 @@
   <data name="ConsoleStartingFile" xml:space="preserve">
     <value>========== Linting {0} ==========</value>
   </data>
+  <data name="ConsoleApplyingSuggestedFixFile" xml:space="preserve">
+    <value>========== Applying fixes ==========</value>
+  </data>
   <data name="ConsoleMSBuildFailedToLoadProjectFile" xml:space="preserve">
     <value>MSBuild could not load the project file {0} because: {1}</value>
   </data>