Flag use of Unicode less-than and greater-than characters in FilePath to be a Windows-only change

.github/workflows/pr-build.yaml

@@ -12,6 +12,9 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
+    env:
+      # Set LANG=C to simulate least-common-denominator target deployment environments:
+      LANG: C
 
     steps:
       - uses: actions/checkout@v2

sjsonnet/src-jvm-native/sjsonnet/SjsonnetMain.scala

@@ -179,7 +179,7 @@ object SjsonnetMain {
                      std: Val.Obj = new Std().Std): Either[String, String] = {
 
     val (jsonnetCode, path) =
-      if (config.exec.value) (file, wd / "\uFE64exec\uFE65")
+      if (config.exec.value) (file, wd / Util.wrapInLessThanGreaterThan("exec"))
       else {
         val p = os.Path(file, wd)
         (os.read(p), p)

sjsonnet/src/sjsonnet/Interpreter.scala

@@ -40,7 +40,7 @@ class Interpreter(extVars: Map[String, String],
 
 
   def parseVar(k: String, v: String) = {
-    resolver.parse(wd / s"\uFE64$k\uFE65", StaticResolvedFile(v))(evaluator).fold(throw _, _._1)
+    resolver.parse(wd / Util.wrapInLessThanGreaterThan(k), StaticResolvedFile(v))(evaluator).fold(throw _, _._1)
   }
 
   lazy val evaluator: Evaluator = createEvaluator(

sjsonnet/src/sjsonnet/Util.scala

@@ -33,4 +33,23 @@ object Util{
         new String(range.dropWhile(_ < 0).takeWhile(_ < s.length).map(s).toArray)
     }
   }
+
+  val isWindows: Boolean = {
+    // This is normally non-null on the JVM, but it might be null in ScalaJS hence the Option:
+    Option(System.getProperty("os.name")).exists(_.toLowerCase.startsWith("windows"))
+  }
+
+  /**
+   * Wrap the given string in '<' and '>' brackets for pretty printing.
+   * On Windows, this uses Unicode less-than and greater-than characters, while on
+   * other platforms it uses ASCII '<' and '>;
+   * see https://github.com/databricks/sjsonnet/pull/208 for motivation and context.
+   */
+  def wrapInLessThanGreaterThan(s: String): String = {
+    if (isWindows) {
+      s"\uFE64$s\uFE65"
+    } else {
+      s"<$s>"
+    }
+  }
 }

sjsonnet/test/src-jvm/sjsonnet/BufferedRandomAccessFileTests.scala

@@ -1,19 +1,20 @@
 package sjsonnet
 
 import utest._
-import java.io.{File, FileWriter}
+
+import java.io.{File, FileOutputStream}
 import java.nio.file.Files
 import scala.util.Random
 
 object BufferedRandomAccessFileTests extends TestSuite {
   // Utility function to create a temporary file with known content
   def createTempFile(content: String): File = {
     val tempFile = Files.createTempFile(null, null).toFile
-    val writer = new FileWriter(tempFile)
+    val fos = new FileOutputStream(tempFile)
     try {
-      writer.write(content)
+      fos.write(content.getBytes("UTF-8"))
     } finally {
-      writer.close()
+      fos.close()
     }
     tempFile
   }