Merge pull request #3128 from certik/pull-request-3127

BUG: fix issue with distutils.exec_command introduced in 1.7.0.

2 files changed, 118 insertions, 14 deletions

diff --git a/numpy/distutils/exec_command.py b/numpy/distutils/exec_command.py
index f05b56429..a469fc5e0 100644
--- a/numpy/distutils/exec_command.py
+++ b/numpy/distutils/exec_command.py
@@ -141,6 +141,19 @@ def _update_environment( **env ):
     for name,value in env.items():
         os.environ[name] = value or ''
 
+def _supports_fileno(stream):
+    """
+    Returns True if 'stream' supports the file descriptor and allows fileno().
+    """
+    if hasattr(stream, 'fileno'):
+        try:
+            r = stream.fileno()
+            return True
+        except IOError:
+            return False
+    else:
+        return False
+
 def exec_command( command,
                   execute_in='', use_shell=None, use_tee = None,
                   _with_python = 1,
@@ -195,7 +208,8 @@ def exec_command( command,
         # _exec_command_posix uses os.system and is faster
         # but not on all platforms os.system will return
         # a correct status.
-        if _with_python and sys.stdout.fileno() == -1:
+        if (_with_python and _supports_fileno(sys.stdout) and
+                            sys.stdout.fileno() == -1):
             st = _exec_command_python(command,
                                       exec_command_dir = exec_dir,
                                       **env)
@@ -349,12 +363,16 @@ def _exec_command( command, use_shell=None, use_tee = None, **env ):
                 argv = [os.environ['COMSPEC'],'/C'] + argv
                 using_command = 1
 
-    so_fileno = sys.stdout.fileno()
-    se_fileno = sys.stderr.fileno()
+    _so_has_fileno = _supports_fileno(sys.stdout)
+    _se_has_fileno = _supports_fileno(sys.stderr)
     so_flush = sys.stdout.flush
     se_flush = sys.stderr.flush
-    so_dup = os.dup(so_fileno)
-    se_dup = os.dup(se_fileno)
+    if _so_has_fileno:
+        so_fileno = sys.stdout.fileno()
+        so_dup = os.dup(so_fileno)
+    if _se_has_fileno:
+        se_fileno = sys.stderr.fileno()
+        se_dup = os.dup(se_fileno)
 
     outfile = temp_file_name()
     fout = open(outfile,'w')
@@ -371,13 +389,16 @@ def _exec_command( command, use_shell=None, use_tee = None, **env ):
 
     so_flush()
     se_flush()
-    os.dup2(fout.fileno(),so_fileno)
-    if using_command:
-        #XXX: disabled for now as it does not work from cmd under win32.
-        #     Tests fail on msys
-        os.dup2(ferr.fileno(),se_fileno)
-    else:
-        os.dup2(fout.fileno(),se_fileno)
+    if _so_has_fileno:
+        os.dup2(fout.fileno(),so_fileno)
+
+    if _se_has_fileno:
+        if using_command:
+            #XXX: disabled for now as it does not work from cmd under win32.
+            #     Tests fail on msys
+            os.dup2(ferr.fileno(),se_fileno)
+        else:
+            os.dup2(fout.fileno(),se_fileno)
     try:
         status = spawn_command(os.P_WAIT,argv0,argv,os.environ)
     except OSError:
@@ -387,8 +408,10 @@ def _exec_command( command, use_shell=None, use_tee = None, **env ):
 
     so_flush()
     se_flush()
-    os.dup2(so_dup,so_fileno)
-    os.dup2(se_dup,se_fileno)
+    if _so_has_fileno:
+        os.dup2(so_dup,so_fileno)
+    if _se_has_fileno:
+        os.dup2(se_dup,se_fileno)
 
     fout.close()
     fout = open_latin1(outfile,'r')
diff --git a/numpy/distutils/tests/test_exec_command.py b/numpy/distutils/tests/test_exec_command.py
new file mode 100644
index 000000000..d23a4485a
--- /dev/null
+++ b/numpy/distutils/tests/test_exec_command.py
@@ -0,0 +1,81 @@
+import os
+import sys
+import StringIO
+from tempfile import TemporaryFile
+
+from numpy.distutils import exec_command
+
+
+class redirect_stdout(object):
+    """Context manager to redirect stdout for exec_command test."""
+    def __init__(self, stdout=None):
+        self._stdout = stdout or sys.stdout
+
+    def __enter__(self):
+        self.old_stdout = sys.stdout
+        sys.stdout = self._stdout
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self._stdout.flush()
+        sys.stdout = self.old_stdout
+
+class redirect_stderr(object):
+    """Context manager to redirect stderr for exec_command test."""
+    def __init__(self, stderr=None):
+        self._stderr = stderr or sys.stderr
+
+    def __enter__(self):
+        self.old_stderr = sys.stderr
+        sys.stderr = self._stderr
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self._stderr.flush()
+        sys.stderr = self.old_stderr
+
+class emulate_nonposix(object):
+    """Context manager to emulate os.name != 'posix' """
+    def __init__(self, osname='non-posix'):
+        self._new_name = osname
+
+    def __enter__(self):
+        self._old_name = os.name
+        os.name = self._new_name
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        os.name = self._old_name
+
+
+def test_exec_command_stdout():
+    # Regression test for gh-2999 and gh-2915.
+    # There are several packages (nose, scipy.weave.inline, Sage inline
+    # Fortran) that replace stdout, in which case it doesn't have a fileno
+    # method.  This is tested here, with a do-nothing command that fails if the
+    # presence of fileno() is assumed in exec_command.
+
+    # The code has a special case for posix systems, so if we are on posix test
+    # both that the special case works and that the generic code works.
+
+    # Test posix version:
+    with redirect_stdout(StringIO.StringIO()):
+        with redirect_stderr(TemporaryFile()):
+            exec_command.exec_command("cd '.'")
+
+    if os.name == 'posix':
+        # Test general (non-posix) version:
+        with emulate_nonposix():
+            with redirect_stdout(StringIO.StringIO()):
+                with redirect_stderr(TemporaryFile()):
+                    exec_command.exec_command("cd '.'")
+
+def test_exec_command_stderr():
+    # Test posix version:
+    with redirect_stdout(TemporaryFile()):
+        with redirect_stderr(StringIO.StringIO()):
+            exec_command.exec_command("cd '.'")
+
+    if os.name == 'posix':
+        # Test general (non-posix) version:
+        with emulate_nonposix():
+            with redirect_stdout(TemporaryFile()):
+                with redirect_stderr(StringIO.StringIO()):
+                    exec_command.exec_command("cd '.'")