Issue #23214: Implement optional BufferedReader, BytesIO read1() argument

3 files changed, 25 insertions, 15 deletions

diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index d0947f0..569527b 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -635,7 +635,7 @@ class BufferedIOBase(IOBase):
     implementation, but wrap one.
     """
 
-    def read(self, size=None):
+    def read(self, size=-1):
         """Read and return up to size bytes, where size is an int.
 
         If the argument is omitted, None, or negative, reads and
@@ -655,7 +655,7 @@ class BufferedIOBase(IOBase):
         """
         self._unsupported("read")
 
-    def read1(self, size=None):
+    def read1(self, size=-1):
         """Read up to size bytes with at most one read() system call,
         where size is an int.
         """
@@ -863,7 +863,7 @@ class BytesIO(BufferedIOBase):
         self._buffer.clear()
         super().close()
 
-    def read(self, size=None):
+    def read(self, size=-1):
         if self.closed:
             raise ValueError("read from closed file")
         if size is None:
@@ -877,7 +877,7 @@ class BytesIO(BufferedIOBase):
         self._pos = newpos
         return bytes(b)
 
-    def read1(self, size):
+    def read1(self, size=-1):
         """This is the same as read.
         """
         return self.read(size)
@@ -1073,12 +1073,12 @@ class BufferedReader(_BufferedIOMixin):
                 self._read_pos = 0
         return self._read_buf[self._read_pos:]
 
-    def read1(self, size):
+    def read1(self, size=-1):
         """Reads up to size bytes, with at most one read() system call."""
         # Returns up to size bytes.  If at least one byte is buffered, we
         # only return buffered bytes.  Otherwise, we do one raw read.
         if size < 0:
-            raise ValueError("number of bytes to read must be positive")
+            size = self.buffer_size
         if size == 0:
             return b""
         with self._read_lock:
@@ -1270,7 +1270,7 @@ class BufferedRWPair(BufferedIOBase):
         self.reader = BufferedReader(reader, buffer_size)
         self.writer = BufferedWriter(writer, buffer_size)
 
-    def read(self, size=None):
+    def read(self, size=-1):
         if size is None:
             size = -1
         return self.reader.read(size)
@@ -1284,7 +1284,7 @@ class BufferedRWPair(BufferedIOBase):
     def peek(self, size=0):
         return self.reader.peek(size)
 
-    def read1(self, size):
+    def read1(self, size=-1):
         return self.reader.read1(size)
 
     def readinto1(self, b):
@@ -1370,7 +1370,7 @@ class BufferedRandom(BufferedWriter, BufferedReader):
         self.flush()
         return BufferedReader.peek(self, size)
 
-    def read1(self, size):
+    def read1(self, size=-1):
         self.flush()
         return BufferedReader.read1(self, size)
 
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 8a2111c..877d3b5 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -1146,6 +1146,7 @@ class BufferedReaderTest(unittest.TestCase, CommonBufferedTests):
         self.assertEqual(b"a", bufio.read(1))
         self.assertEqual(b"b", bufio.read1(1))
         self.assertEqual(rawio._reads, 1)
+        self.assertEqual(b"", bufio.read1(0))
         self.assertEqual(b"c", bufio.read1(100))
         self.assertEqual(rawio._reads, 1)
         self.assertEqual(b"d", bufio.read1(100))
@@ -1154,8 +1155,17 @@ class BufferedReaderTest(unittest.TestCase, CommonBufferedTests):
         self.assertEqual(rawio._reads, 3)
         self.assertEqual(b"", bufio.read1(100))
         self.assertEqual(rawio._reads, 4)
-        # Invalid args
-        self.assertRaises(ValueError, bufio.read1, -1)
+
+    def test_read1_arbitrary(self):
+        rawio = self.MockRawIO((b"abc", b"d", b"efg"))
+        bufio = self.tp(rawio)
+        self.assertEqual(b"a", bufio.read(1))
+        self.assertEqual(b"bc", bufio.read1())
+        self.assertEqual(b"d", bufio.read1())
+        self.assertEqual(b"efg", bufio.read1(-1))
+        self.assertEqual(rawio._reads, 3)
+        self.assertEqual(b"", bufio.read1())
+        self.assertEqual(rawio._reads, 4)
 
     def test_readinto(self):
         rawio = self.MockRawIO((b"abc", b"d", b"efg"))
@@ -1806,6 +1816,7 @@ class BufferedRWPairTest(unittest.TestCase):
         pair = self.tp(self.BytesIO(b"abcdef"), self.MockRawIO())
 
         self.assertEqual(pair.read1(3), b"abc")
+        self.assertEqual(pair.read1(), b"def")
 
     def test_readinto(self):
         for method in ("readinto", "readinto1"):
@@ -3467,6 +3478,7 @@ class MiscIOTest(unittest.TestCase):
             self.assertRaises(ValueError, f.read)
             if hasattr(f, "read1"):
                 self.assertRaises(ValueError, f.read1, 1024)
+                self.assertRaises(ValueError, f.read1)
             if hasattr(f, "readall"):
                 self.assertRaises(ValueError, f.readall)
             if hasattr(f, "readinto"):
diff --git a/Lib/test/test_memoryio.py b/Lib/test/test_memoryio.py
index 55b693e..80055ce 100644
--- a/Lib/test/test_memoryio.py
+++ b/Lib/test/test_memoryio.py
@@ -437,10 +437,8 @@ class PyBytesIOTest(MemoryTestMixin, MemorySeekTestMixin, unittest.TestCase):
 
     def test_read1(self):
         buf = self.buftype("1234567890")
-        memio = self.ioclass(buf)
-
-        self.assertRaises(TypeError, memio.read1)
-        self.assertEqual(memio.read(), buf)
+        self.assertEqual(self.ioclass(buf).read1(), buf)
+        self.assertEqual(self.ioclass(buf).read1(-1), buf)
 
     def test_readinto(self):
         buf = self.buftype("1234567890")