Change modifiedTime definitions

core/src/main/scala/sbt/librarymanagement/RichUpdateReport.scala

@@ -18,9 +18,9 @@ final class RichUpdateReport(report: UpdateReport) {
           (f,
            // TODO: The list of files may also contain some odd files that do not actually exist like:
            // "./target/ivyhome/resolution-cache/com.example/foo/0.4.0/resolved.xml.xml".
-           // IO.lastModified() will just return zero, but the list of files should not contain such
+           // IO.getModifiedTimeOrZero() will just return zero, but the list of files should not contain such
            // files to begin with, in principle.
-           IO.lastModified(f)
+           IO.getModifiedTimeOrZero(f))
       )
       .toMap
     UpdateReport(report.cachedDescriptor, report.configurations, report.stats, stamps)

ivy/src/main/scala/sbt/internal/librarymanagement/ivyint/GigahorseUrlHandler.scala

@@ -149,7 +149,7 @@ class GigahorseUrlHandler extends AbstractURLHandler {
 
       val lastModified = lastModifiedTimestamp(response)
       if (lastModified > 0) {
-        IO.setLastModified(dest, lastModified)
+        IO.setModifiedTimeOrFalse(dest, lastModified)
       }
 
       if (l != null) {

project/Util.scala

@@ -26,7 +26,7 @@ object Util {
     val timestamp = formatter.format(new Date)
     val content = versionLine(version) + "\ntimestamp=" + timestamp
     val f = dir / "xsbt.version.properties"
-    // TODO: replace lastModified() with sbt.io.IO.lastModified(), once the build
+    // TODO: replace lastModified() with sbt.io.IO.getModifiedTimeOrZero(), once the build
     // has been upgraded to a version of sbt that includes that call.
     if (!f.exists || f.lastModified < lastCompilationTime(analysis) || !containsVersion(f, version)) {
       s.log.info("Writing version information to " + f + " :\n" + content)