feat: upgrade FScript to 0.40 (with Env support)

CHANGELOG.md

@@ -4,6 +4,9 @@ All notable changes to Terrabuild are documented in this file.
 
 ## [Unreleased]
 
+- Upgrade Terrabuild FScript runtime to 0.40.0 and initialize `Env` (`ScriptName`, `Arguments`) when loading `.fss` extension scripts.
+- Fix FScript `Env` prelude injection to preserve leading `import` directives in embedded scripts.
+
 ## [0.189.4-next]
 
 - Create annotated release tags in `release-prepare` so `git push --follow-tags` pushes releases

src/Terrabuild.Scripting.Tests/Scripting.fs

@@ -122,6 +122,21 @@ let invokeFScriptMethodWithStructuredArgumentsDefaults() =
     let res = invocable.Value.Invoke<string> args
     res |> should equal "build|0|<none>"
 
+[<Test>]
+let invokeFScriptMethodHasEnvInitialized() =
+    let root = NUnit.Framework.TestContext.CurrentContext.TestDirectory
+    let script = Terrabuild.Scripting.loadScript root [] "TestFiles/Env.fss"
+    let invocable = script.GetMethod("run")
+    let context = { ActionContext.Debug = false
+                    ActionContext.CI = false
+                    ActionContext.Command = "run"
+                    ActionContext.Hash = "abc"
+                    ActionContext.Directory = "TestFiles"
+                    ActionContext.Batch = None }
+    let args = Value.Map (Map [ "context", Value.Object context ])
+    let res = invocable.Value.Invoke<string> args
+    res |> should equal "Env.fss|0"
+
 [<Test>]
 let invokeFScriptMethodMissingContextFails() =
     let root = NUnit.Framework.TestContext.CurrentContext.TestDirectory

src/Terrabuild.Scripting.Tests/TestFiles/Env.fss

@@ -0,0 +1,21 @@
+[<export>]
+let run (context: {| Command: string |}) =
+    let scriptName =
+        match Env.ScriptName with
+        | Some name -> name
+        | None -> "<none>"
+
+    $"{scriptName}|{Env.Arguments |> List.length}"
+
+type ExportFlag =
+  | Dispatch
+  | Default
+  | Batchable
+  | Never
+  | Local
+  | External
+  | Remote
+
+{
+  [nameof run] = []
+}

src/Terrabuild.Scripting/Scripting.fs

@@ -549,11 +549,87 @@ let private toFScriptScript (loaded: FScript.Runtime.ScriptHost.LoadedScript) =
     let dispatchMethod, defaultMethod = Descriptor.ResolveDispatchAndDefault descriptor
     Script(FScript(loaded, descriptor, dispatchMethod, defaultMethod))
 
+let private toFScriptStringLiteral (value: string) =
+    let escaped =
+        value
+            .Replace("\\", "\\\\", StringComparison.Ordinal)
+            .Replace("\"", "\\\"", StringComparison.Ordinal)
+    $"\"{escaped}\""
+
+let private prependEnvironmentBinding (scriptName: string option) (arguments: string list) (source: string) =
+    let scriptNameLiteral =
+        match scriptName with
+        | Some value -> $"Some {toFScriptStringLiteral value}"
+        | None -> "None"
+
+    let argumentsLiteral =
+        match arguments with
+        | [] -> "[]"
+        | values ->
+            values
+            |> List.map toFScriptStringLiteral
+            |> String.concat "; "
+            |> sprintf "[%s]"
+
+    let prelude =
+        String.concat
+            "\n"
+            [ "let asEnvironment (value: Environment) = value"
+              $"let Env = asEnvironment {{ ScriptName = {scriptNameLiteral}; Arguments = {argumentsLiteral} }}"
+              "" ]
+
+    let newline =
+        if source.Contains("\r\n", StringComparison.Ordinal) then "\r\n"
+        else "\n"
+
+    let lines =
+        source.Replace("\r\n", "\n", StringComparison.Ordinal).Split('\n')
+
+    let isCommentOrBlank (line: string) =
+        let trimmed = line.Trim()
+        String.IsNullOrWhiteSpace(trimmed) || trimmed.StartsWith("//", StringComparison.Ordinal)
+
+    let isImport (line: string) =
+        line.TrimStart().StartsWith("import ", StringComparison.Ordinal)
+
+    let mutable index = 0
+    let mutable seenImport = false
+    let mutable keepScanning = true
+
+    while index < lines.Length && keepScanning do
+        let line = lines[index]
+        if isImport line then
+            seenImport <- true
+            index <- index + 1
+        elif isCommentOrBlank line then
+            index <- index + 1
+        else
+            keepScanning <- false
+
+    let insertionIndex = if seenImport then index else 0
+    let before = lines |> Array.take insertionIndex |> String.concat newline
+    let after = lines |> Array.skip insertionIndex |> String.concat newline
+
+    if insertionIndex = 0 then
+        prelude + source
+    elif String.IsNullOrEmpty(after) then
+        before + newline + prelude
+    else
+        before + newline + prelude + after
+
 let private loadFScript (rootDirectory: string) (scriptFile: string) =
 
     let fullPath = Path.GetFullPath(scriptFile)
     let externs = FScript.Runtime.Registry.all { FScript.Runtime.HostContext.RootDirectory = rootDirectory }
-    let loaded = FScript.Runtime.ScriptHost.loadFile externs fullPath
+    let scriptName = Path.GetFileName(fullPath) |> Option.ofObj
+    let entrySource = File.ReadAllText(fullPath) |> prependEnvironmentBinding scriptName []
+    let loaded =
+        FScript.Runtime.ScriptHost.loadSourceWithIncludes
+            externs
+            rootDirectory
+            fullPath
+            entrySource
+            (fun resolvedPath -> File.ReadAllText(resolvedPath) |> Some)
     toFScriptScript loaded
 
 let private loadFScriptFromSourceWithIncludes
@@ -563,6 +639,8 @@ let private loadFScriptFromSourceWithIncludes
     (entrySource: string)
     (resolveImportedSource: string -> string option) =
     let externs = FScript.Runtime.Registry.all { FScript.Runtime.HostContext.RootDirectory = hostRootDirectory }
+    let scriptName = Path.GetFileName(entryFile) |> Option.ofObj
+    let entrySource = entrySource |> prependEnvironmentBinding scriptName []
     let loaded =
         FScript.Runtime.ScriptHost.loadSourceWithIncludes
             externs

src/Terrabuild.Scripting/Terrabuild.Scripting.fsproj

@@ -11,8 +11,8 @@
 
   <ItemGroup>
     <PackageReference Include="FSharp.Compiler.Service" Version="43.10.102" />
-    <PackageReference Include="MagnusOpera.FScript.Language" Version="0.37.0" />
-    <PackageReference Include="MagnusOpera.FScript.Runtime" Version="0.37.0" />
+    <PackageReference Include="MagnusOpera.FScript.Language" Version="0.40.0" />
+    <PackageReference Include="MagnusOpera.FScript.Runtime" Version="0.40.0" />
   </ItemGroup>
 
   <ItemGroup>