bpo-29435: Allow is_tarfile to take a filelike obj (GH-18090)

`is_tarfile()` now supports `name` being a file or file-like object.

1 files changed, 6 insertions, 1 deletions

diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 2c06f9160c..d0b748cea1 100755
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -2461,9 +2461,14 @@ class TarFile(object):
 def is_tarfile(name):
     """Return True if name points to a tar archive that we
        are able to handle, else return False.
+
+       'name' should be a string, file, or file-like object.
     """
     try:
-        t = open(name)
+        if hasattr(name, "read"):
+            t = open(fileobj=name)
+        else:
+            t = open(name)
         t.close()
         return True
     except TarError: