tarfile: Fix FileSection.skip to not rely on extended readinto args.

python-stdlib/tarfile/manifest.py

@@ -1,4 +1,4 @@
-metadata(description="Read-only implementation of Python's tarfile.", version="0.4.1")
+metadata(description="Read-only implementation of Python's tarfile.", version="0.4.2")
 
 # Originally written by Paul Sokolovsky.
 

python-stdlib/tarfile/tarfile/__init__.py

@@ -55,9 +55,12 @@ def skip(self):
         if sz:
             buf = bytearray(16)
             while sz:
-                s = min(sz, 16)
-                self.f.readinto(buf, s)
-                sz -= s
+                if sz >= 16:
+                    self.f.readinto(buf)
+                    sz -= 16
+                else:
+                    self.f.read(sz)
+                    sz = 0
 
 
 class TarInfo:

python-stdlib/tarfile/test_tarfile.py

@@ -0,0 +1,45 @@
+import tarfile
+import unittest
+
+
+test_tar_contents = (
+    ("a", "file", 2),
+    ("b", "file", 2),
+    ("dir/", "dir", 0),
+    ("dir/c", "file", 2),
+    ("dir/d", "file", 2),
+    ("tar.tar", "file", 10240),
+)
+
+test_sub_tar_contents = (
+    ("e", "file", 2),
+    ("f", "file", 2),
+)
+
+
+class TestTarFile(unittest.TestCase):
+    def check_contents(self, expected, tf):
+        for i, file in enumerate(tf):
+            name, type, size = expected[i]
+            self.assertEqual(file.name, name)
+            self.assertEqual(file.type, type)
+            self.assertEqual(file.size, size)
+
+    def test_iter(self):
+        tf = tarfile.TarFile("test.tar")
+        for _ in range(6):
+            self.assertIsInstance(next(tf), tarfile.TarInfo)
+        with self.assertRaises(StopIteration):
+            next(tf)
+
+    def test_contents(self):
+        tf = tarfile.TarFile("test.tar")
+        self.check_contents(test_tar_contents, tf)
+
+    def test_nested_tar(self):
+        tf = tarfile.TarFile("test.tar")
+        for file in tf:
+            if file.name == "tar.tar":
+                subf = tf.extractfile(file)
+                subtf = tarfile.TarFile(fileobj=subf)
+                self.check_contents(test_sub_tar_contents, subtf)

tools/ci.sh

@@ -90,6 +90,7 @@ function ci_package_tests_run {
         python-stdlib/pathlib \
         python-stdlib/quopri \
         python-stdlib/shutil \
+        python-stdlib/tarfile \
         python-stdlib/tempfile \
         python-stdlib/time \
         python-stdlib/unittest/tests \