add ignoreErrors to os.remove.all

Author: lihaoyi

Readme.adoc

@@ -1028,7 +1028,7 @@ If you wish to remove the destination of a symlink, use
 
 [source,scala]
 ----
-os.remove.all(target: Path): Unit
+os.remove.all(target: Path, ignoreErrors: Boolean = false): Unit
 ----
 
 Remove the target file or folder; if it is a folder and not empty, recursively
@@ -1063,6 +1063,12 @@ os.exists(wd / "misc/broken-symlink", followLinks = false) ==> false
 If you wish to remove the destination of a symlink, use
 <<os-readlink>>.
 
+``os.remove.all`` removes nested files and folders one at a time, and any failure
+in removing a file (e.g. due to permissions) or folder (e.g. due to someone concurrently
+creating a file within it) causes an error to be thrown and terminates the removal early.
+You can pass `ignoreErrors = false` to continue with the deletion of other files
+even if some files or folders failed to be removed.
+
 ==== `os.hardlink`
 
 [source,scala]

os/src/FileOps.scala

@@ -329,16 +329,21 @@ object remove extends Function1[Path, Boolean] {
   }
 
   object all extends Function1[Path, Unit] {
-    def apply(target: Path) = {
+    def apply(target: Path): Unit = apply(target, ignoreErrors = false)
+    def apply(target: Path, ignoreErrors: Boolean = false): Unit = {
       require(target.segmentCount != 0, s"Cannot remove a root directory: $target")
       checker.value.onWrite(target)
 
       val nioTarget = target.wrapped
       if (Files.exists(nioTarget, LinkOption.NOFOLLOW_LINKS)) {
         if (Files.isDirectory(nioTarget, LinkOption.NOFOLLOW_LINKS)) {
-          walk.stream(target, preOrder = false).foreach(remove(_))
+          for (p <- walk.stream(target, preOrder = false)) {
+            try remove(p)
+            catch { case e: Throwable if ignoreErrors => /*ignore*/ }
+          }
         }
-        Files.delete(nioTarget)
+        try Files.delete(nioTarget)
+        catch { case e: Throwable if ignoreErrors => /*ignore*/ }
       }
     }
   }