Fix File to String conversion on Windows

.github/workflows/ci.yml

@@ -1,4 +1,3 @@
-
 name: CI
 on:
   pull_request:
@@ -14,6 +13,9 @@ jobs:
             java: 8
             jobtype: 1
           - os: ubuntu-latest
+            java: 11
+            jobtype: 2
+          - os: windows-latest
             java: 11
             jobtype: 1
     runs-on: ${{ matrix.os }}
@@ -34,4 +36,24 @@ jobs:
         path: ~/.sbt
         key: ${{ runner.os }}-sbt-cache-${{ hashFiles('**/*.sbt') }}-${{ hashFiles('project/build.properties') }}
     - name: Build and test
-      run: echo hello GitHub
+      run: |
+        case ${{ matrix.jobtype }} in
+          1)
+            sbt -v "+test;"
+            ;;
+          2)
+            sbt -v "+test;"
+            SCALA_VERSION=2.12.12
+            sbt -v "++$SCALA_VERSION!" mimaReportBinaryIssues
+            sbt -v "++$SCALA_VERSION!" "benchmark/jmh:run -i 10 -wi 3 -f1 -t1"
+            ;;
+          *)
+            echo unknown jobtype
+            exit 1
+        esac
+        rm -rf "$HOME/.ivy2/local" || true
+        find $HOME/Library/Caches/Coursier/v1        -name "ivydata-*.properties" -delete || true
+        find $HOME/.ivy2/cache                       -name "ivydata-*.properties" -delete || true
+        find $HOME/.cache/coursier/v1                -name "ivydata-*.properties" -delete || true
+        find $HOME/.sbt                              -name "*.lock"               -delete || true
+      shell: bash

core/src/main/scala/sjsonnew/JavaExtraFormats.scala

@@ -16,13 +16,14 @@
 
 package sjsonnew
 
-import java.util.{ UUID, Optional }
 import java.net.{ URI, URL }
 import java.io.File
 import java.math.{ BigInteger, BigDecimal => JBigDecimal }
+import java.util.{ Locale, Optional, UUID }
 
 trait JavaExtraFormats {
   this: PrimitiveFormats with AdditionalFormats with IsoFormats =>
+  import JavaExtraFormats._
 
   private[this] type JF[A] = JsonFormat[A] // simple alias for reduced verbosity
 
@@ -43,17 +44,27 @@ trait JavaExtraFormats {
 
   implicit val fileStringIso: IsoString[File] = IsoString.iso[File](
     (f: File) => {
-      if (f.isAbsolute) {
+      val p = f.getPath
+      if (p.startsWith(File.separatorChar.toString) && isWindows) {
+        if (p.startsWith("""\\""")) {
+          // supports \\laptop\My Documents\Some.doc on Windows
+          new URI(FileScheme, normalizeName(p), null).toASCIIString
+        }
+        else {
+          // supports /tmp on Windows
+          new URI(FileScheme, "", normalizeName(p), null).toASCIIString
+        }
+      } else if (f.isAbsolute) {
         //not using f.toURI to avoid filesystem syscalls
         //we use empty string as host to force file:// instead of just file:
-        new URI(FileScheme, "", normalizeName(slashify(f.getAbsolutePath)), null).toASCIIString
+        new URI(FileScheme, "", normalizeName(ensureHeadSlash(f.getAbsolutePath)), null).toASCIIString
       } else {
         new URI(null, normalizeName(f.getPath), null).toASCIIString
       }
     },
     (s: String) => uriToFile(new URI(s)))
 
-  private[this] def slashify(name: String) = {
+  private[this] def ensureHeadSlash(name: String) = {
     if(name.nonEmpty && name.head != File.separatorChar) File.separatorChar + name
     else name
   }
@@ -100,3 +111,8 @@ trait JavaExtraFormats {
       }
   }
 }
+
+object JavaExtraFormats {
+  private[sjsonnew] lazy val isWindows: Boolean =
+    System.getProperty("os.name").toLowerCase(Locale.ENGLISH).contains("windows")
+}

support/spray/src/test/scala/sjsonnew/support/spray/JavaExtraFormatsSpec.scala

@@ -19,11 +19,13 @@ package support.spray
 
 import spray.json.{ JsValue, JsNumber, JsString, JsNull, JsTrue, JsFalse, JsObject }
 import org.specs2.mutable._
-import java.util.{ UUID, Optional }
 import java.net.{ URI, URL }
 import java.io.File
+import java.util.{ Locale, Optional, UUID }
 
 class JavaExtraFormatsSpec extends Specification with BasicJsonProtocol {
+  import JavaExtraFormats._
+
   case class Person(name: Optional[String], value: Optional[Int])
   implicit object PersonFormat extends JsonFormat[Person] {
     def write[J](x: Person, builder: Builder[J]): Unit = {
@@ -91,6 +93,18 @@ class JavaExtraFormatsSpec extends Specification with BasicJsonProtocol {
     "convert the JsString back to the relative path" in {
       Converter.fromJsonUnsafe[File](JsString("src/main")) mustEqual f2
     }
+    "convert an absolute path on Windows" in {
+      if (isWindows) Converter.toJsonUnsafe(new File("""C:\Documents and Settings\""")) mustEqual JsString("file:///C:/Documents%20and%20Settings")
+      else ok
+    }
+    "convert a relative path on Windows" in {
+      if (isWindows) Converter.toJsonUnsafe(new File("""..\My Documents\test""")) mustEqual JsString("../My%20Documents/test")
+      else ok
+    }
+    "convert a UNC path on Windows" in {
+      if (isWindows) Converter.toJsonUnsafe(new File("""\\laptop\My Documents\Some.doc""")) mustEqual JsString("file://laptop/My%20Documents/Some.doc")
+      else ok
+    }
   }
 
   "The optionalFormat" should {