Merge tag 'upstream/1.15.2'

Upstream version 1.15.2

1 files changed, 12 insertions, 4 deletions

diff --git a/paramiko/file.py b/paramiko/file.py
index 311e198..e3b0a16 100644
--- a/paramiko/file.py
+++ b/paramiko/file.py
@@ -206,6 +206,7 @@ class BufferedFile (ClosingContextManager):
         if not (self._flags & self.FLAG_READ):
             raise IOError('File not open for reading')
         line = self._rbuffer
+        truncated = False
         while True:
             if self._at_trailing_cr and (self._flags & self.FLAG_UNIVERSAL_NEWLINE) and (len(line) > 0):
                 # edge case: the newline may be '\r\n' and we may have read
@@ -220,11 +221,11 @@ class BufferedFile (ClosingContextManager):
             # enough.
             if (size is not None) and (size >= 0):
                 if len(line) >= size:
-                    # truncate line and return
+                    # truncate line
                     self._rbuffer = line[size:]
                     line = line[:size]
-                    self._pos += len(line)
-                    return line if self._flags & self.FLAG_BINARY else u(line)
+                    truncated = True
+                    break
                 n = size - len(line)
             else:
                 n = self._bufsize
@@ -246,10 +247,17 @@ class BufferedFile (ClosingContextManager):
             rpos = line.find(cr_byte)
             if (rpos >= 0) and (rpos < pos or pos < 0):
                 pos = rpos
+        if pos == -1:
+            # we couldn't find a newline in the truncated string, return it
+            self._pos += len(line)
+            return line if self._flags & self.FLAG_BINARY else u(line)
         xpos = pos + 1
         if (line[pos] == cr_byte_value) and (xpos < len(line)) and (line[xpos] == linefeed_byte_value):
             xpos += 1
-        self._rbuffer = line[xpos:]
+        # if the string was truncated, _rbuffer needs to have the string after 
+        # the newline character plus the truncated part of the line we stored
+        # earlier in _rbuffer
+        self._rbuffer = line[xpos:] + self._rbuffer if truncated else line[xpos:]
         lf = line[pos:xpos]
         line = line[:pos] + linefeed_byte
         if (len(self._rbuffer) == 0) and (lf == cr_byte):