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compile() raises a SyntaxError if the source code it is given contains
trailing spaces or a trailing carriage return character, but this does
happen if the same source code is imported or executed.
import subprocess
data = "if True:\n pass\n "
filename = "/tmp/test.py"
fh = open(filename, "w")
fh.write(data)
fh.close()
subprocess.check_call(["python", filename])
subprocess.check_call(["python", "-c", "import test"], cwd="/tmp")
compile(data, filename, "exec")
This gives:
Traceback (most recent call last):
 File "whitespace.py", line 11, in <module>
 compile(data, filename, "exec")
 File "/tmp/test.py", line 3
 
SyntaxError: invalid syntax
This also happens if the data is changed to:
data = "if True:\n pass\r"

Both differences are covered in the 2.x docs:
"When compiling multi-line statements, two caveats apply: line endings
must be represented by a single newline character ('\n'), and the input
must be terminated by at least one newline character.
The \r difference is not really a difference because \r is replaced by
\n before import starts compiling. I suspect that EOF effectively gets
converted to \n also. The doc issue is that 'must be terminated...' is
not always true.
This caveat is missing in 3.0, even though the limitation is the same. 
see #4118.
I thought this was discussed in a c.l.p thread.