why did git mv not delete this?

coro/httpd/read_stream.py

-# -*- Mode: Python -*-
-
-import sys
-W = sys.stderr.write
-
-class socket_producer:
-    def __init__ (self, conn, buffer_size=8000):
-        self.conn = conn
-        self.buffer_size = buffer_size
-    def next (self):
-        return self.conn.recv (self.buffer_size)
-
-def sock_stream (sock):
-    return buffered_stream (socket_producer (sock).next)
-
-class buffered_stream:
-
-    def __init__ (self, producer):
-        self.producer = producer
-        self.buffer = ''
-
-    def gen_read_until (self, delim):
-        "generate pieces of input up to and including <delim>, then StopIteration"
-        ld = len(delim)
-        m = 0
-        while 1:
-            if not self.buffer:
-                self.buffer = self.producer()
-                if not self.buffer:
-                    # eof
-                    yield ''
-                    return
-            i = 0
-            while i < len (self.buffer):
-                if self.buffer[i] == delim[m]:
-                    m += 1
-                    if m == ld:
-                        result, self.buffer = self.buffer[:i+1], self.buffer[i+1:]
-                        yield result
-                        return
-                else:
-                    m = 0
-                i += 1
-            block, self.buffer = self.buffer, ''
-            yield block
-
-    def gen_read_until_dfa (self, dfa):
-        "generate pieces of input up to and including a match on <dfa>, then StopIteration"
-        m = 0
-        while 1:
-            if not self.buffer:
-                self.buffer = self.producer()
-                if not self.buffer:
-                    # eof
-                    yield ''
-                    return
-            i = 0
-            while i < len (self.buffer):
-                if dfa.consume (self.buffer[i]):
-                    result, self.buffer = self.buffer[:i+1], self.buffer[i+1:]
-                    yield result
-                    return
-                i += 1
-            block, self.buffer = self.buffer, ''
-            yield block
-
-    def gen_read_exact (self, size):
-        "generate pieces of input up to <size> bytes, then StopIteration"
-        remain = size
-        while remain:
-            if len (self.buffer) >= remain:
-                result, self.buffer = self.buffer[:remain], self.buffer[remain:]
-                yield result
-                return
-            else:
-                piece, self.buffer = self.buffer, self.producer()
-                remain -= len (piece)
-                yield piece
-                if not self.buffer:
-                    # eof
-                    yield ''
-                    return
-
-    def read_until (self, delim, join=True):
-        "read until <delim>.  return a list of parts unless <join> is True"
-        result = ( x for x in self.gen_read_until (delim) )
-        if join:
-            return ''.join (result)
-        else:
-            return result
-
-    def read_exact (self, size, join=True):
-        "read exactly <size> bytes.  return a list of parts unless <join> is True"
-        result = ( x for x in self.gen_read_exact (size) )
-        if join:
-            return ''.join (result)
-        else:
-            return result
-
-    def flush (self):
-        "flush this stream's buffer"
-        result, self.buffer = self.buffer, ''
-        return result
-
-    def read_line (self, delim='\r\n'):
-        "read a CRLF-delimited line from this stream"
-        return self.read_until (delim)
-
-    def read_all (self):
-        "read from self.producer until the stream terminates"
-        if self.buffer:
-            yield self.flush()
-        while 1:
-            block = self.producer()
-            if not block:
-                return
-            else:
-                yield block
-