Overhaul external process calls

This commits starts with moving from `os.system` to the `subprocess`
module and captures stderr and includes it in the exceptions.

For more information see matplotlibgh-7490.

Author: tomspur

doc/make.py

@@ -175,8 +175,8 @@ def latex():
         os.chdir('build/latex')
 
         # Call the makefile produced by sphinx...
-        if os.system('make'):
-            raise SystemExit("Rendering LaTeX failed.")
+        if subprocess.call("make"):
+            raise SystemExit("Rendering LaTeX failed with.")
 
         os.chdir('../..')
     else:
@@ -198,8 +198,8 @@ def texinfo():
         os.chdir('build/texinfo')
 
         # Call the makefile produced by sphinx...
-        if os.system('make'):
-            raise SystemExit("Rendering Texinfo failed.")
+        if subprocess.call("make"):
+            raise SystemExit("Rendering Texinfo failed with.")
 
         os.chdir('../..')
     else:

lib/matplotlib/backends/backend_ps.py

@@ -23,6 +23,7 @@ def _fn_name(): return sys._getframe(1).f_code.co_name
 
 from matplotlib.cbook import is_string_like, get_realpath_and_stat, \
     is_writable_file_like, maxdict, file_requires_unicode
+from matplotlib.compat.subprocess import subprocess
 from matplotlib.figure import Figure
 
 from matplotlib.font_manager import findfont, is_opentype_cff_font, get_font
@@ -83,8 +84,7 @@ def gs_version(self):
             pass
 
         from matplotlib.compat.subprocess import Popen, PIPE
-        s = Popen(self.gs_exe + " --version",
-                     shell=True, stdout=PIPE)
+        s = Popen([self.gs_exe, "--version"], stdout=PIPE)
         pipe, stderr = s.communicate()
         if six.PY3:
             ver = pipe.decode('ascii')
@@ -1469,27 +1469,32 @@ def convert_psfrags(tmpfile, psfrags, font_preamble, custom_preamble,
     command = '%s cd "%s" && latex -interaction=nonstopmode "%s" > "%s"'\
                 %(precmd, tmpdir, latexfile, outfile)
     verbose.report(command, 'debug')
-    exit_status = os.system(command)
-
-    with io.open(outfile, 'rb') as fh:
-        if exit_status:
-            raise RuntimeError('LaTeX was not able to process your file:\
-    \nHere is the full report generated by LaTeX: \n\n%s'% fh.read())
-        else:
+    try:
+        output = subprocess.check_output(command, shell=True,
+                                         stderr=subprocess.STDOUT)
+    except subprocess.CalledProcessError as exc:
+        with io.open(outfile, 'rb') as fh:
+            raise RuntimeError('LaTeX was not able to process your file: '
+                               'Here is the full report generated by LaTeX'
+                               '\n\n%s'% (fh.read()))
+    else:
+        with io.open(outfile, 'rb') as fh:
             verbose.report(fh.read(), 'debug')
     os.remove(outfile)
 
     command = '%s cd "%s" && dvips -q -R0 -o "%s" "%s" > "%s"'%(precmd, tmpdir,
                 os.path.split(psfile)[-1], os.path.split(dvifile)[-1], outfile)
     verbose.report(command, 'debug')
-    exit_status = os.system(command)
-
-    with io.open(outfile, 'rb') as fh:
-        if exit_status:
-            raise RuntimeError('dvips was not able to \
-    process the following file:\n%s\nHere is the full report generated by dvips: \
-    \n\n'% dvifile + fh.read())
-        else:
+    try:
+        output = subprocess.check_output(command, shell=True,
+                                         stderr=subprocess.STDOUT)
+    except subprocess.CalledProcessError as exc:
+        with io.open(outfile, 'rb') as fh:
+            raise RuntimeError('dvips was not able to process the following '
+                               'file:\n%s\nHere is the full report generated '
+                               'by dvips: \n\n'% dvifile + fh.read())
+    else:
+        with io.open(outfile, 'rb') as fh:
             verbose.report(fh.read(), 'debug')
     os.remove(outfile)
     os.remove(epsfile)
@@ -1528,30 +1533,27 @@ def gs_distill(tmpfile, eps=False, ptype='letter', bbox=None, rotated=False):
     outfile = tmpfile + '.output'
     dpi = rcParams['ps.distiller.res']
 
-
     gs_exe = ps_backend_helper.gs_exe
     if ps_backend_helper.supports_ps2write: # gs version >= 9
         device_name = "ps2write"
     else:
         device_name = "pswrite"
 
-    command = '%s -dBATCH -dNOPAUSE -r%d -sDEVICE=%s %s -sOutputFile="%s" \
-                "%s" > "%s"'% (gs_exe, dpi, device_name,
-                               paper_option, psfile, tmpfile, outfile)
-
+    command = [gs_exe, "-dBATCH", "-dNOPAUSE", "-r%d" % dpi,
+               "-sDEVICE=%s" % device_name, paper_option,
+               "-sOutputFile=%s" % psfile, tmpfile]
     verbose.report(command, 'debug')
-    exit_status = os.system(command)
-
-    with io.open(outfile, 'rb') as fh:
-        if exit_status:
-            output = fh.read()
-            m = "\n".join(["ghostscript was not able to process your image.",
-                           "Here is the full report generated by ghostscript:",
-                           "",
-                           "%s"])
-            # use % to prevent problems with bytes
-            raise RuntimeError(m % output)
-        else:
+    try:
+        with open(outfile, "w") as fout:
+            subprocess.check_call(command,
+                                  stdout=fout, stderr=subprocess.STDOUT)
+    except subprocess.CalledProcessError as exc:
+        with io.open(outfile, 'rb') as fh:
+            raise RuntimeError('ghostscript was not able to process your '
+                               'image.\nHere is the full report generated by '
+                               'ghostscript: %s\n\n' % fh.read())
+    else:
+        with io.open(outfile, 'rb') as fh:
             verbose.report(fh.read(), 'debug')
     os.remove(outfile)
     os.remove(tmpfile)
@@ -1584,33 +1586,55 @@ def xpdf_distill(tmpfile, eps=False, ptype='letter', bbox=None, rotated=False):
     psfile = tmpfile + '.ps'
     outfile = tmpfile + '.output'
 
-    if eps: paper_option = "-dEPSCrop"
-    else: paper_option = "-sPAPERSIZE=%s" % ptype
-
-    command = 'ps2pdf -dAutoFilterColorImages=false \
--dAutoFilterGrayImages=false -sGrayImageFilter=FlateEncode \
--sColorImageFilter=FlateEncode %s "%s" "%s" > "%s"'% \
-(paper_option, tmpfile, pdffile, outfile)
-    if sys.platform == 'win32': command = command.replace('=', '#')
-    verbose.report(command, 'debug')
-    exit_status = os.system(command)
-    with io.open(outfile, 'rb') as fh:
-        if exit_status:
-            raise RuntimeError('ps2pdf was not able to process your \
-image.\nHere is the report generated by ghostscript:\n\n' + fh.read())
+    if eps:
+        paper_option = "-dEPSCrop"
+    else:
+        if sys.platform == "win32":
+            paper_option = "-sPAPERSIZE#%s" % ptype
         else:
+            paper_option = "-sPAPERSIZE=%s" % ptype
+
+    if sys.platform == "win32":
+        command = ["ps2pdf", "-dAutoFilterColorImages#false",
+                   "-dAutoFilterGrayImages#false",
+                   "-sGrayImageFilter#FlateEncode",
+                   "-sColorImageFilter#FlateEncode", paper_option, tmpfile,
+                   pdffile]
+    else:
+        command = ["ps2pdf", "-dAutoFilterColorImages=false",
+                   "-dAutoFilterGrayImages=false",
+                   "-sGrayImageFilter=FlateEncode",
+                   "-sColorImageFilter=FlateEncode", paper_option, tmpfile,
+                   pdffile]
+    verbose.report(command, 'debug')
+
+    try:
+        with open(outfile, "w") as fout:
+            subprocess.check_call(command,
+                                  stdout=fout, stderr=subprocess.STDOUT)
+    except subprocess.CalledProcessError as exc:
+        with io.open(outfile, 'rb') as fh:
+            raise RuntimeError('ps2pdf was not able to process your image.\n'
+                               'Here is the report generated by ps2pdf: '
+                               '%s\n\n' % fh.read())
+    else:
+        with io.open(outfile, 'rb') as fh:
             verbose.report(fh.read(), 'debug')
     os.remove(outfile)
-    command = 'pdftops -paper match -level2 "%s" "%s" > "%s"'% \
-                (pdffile, psfile, outfile)
-    verbose.report(command, 'debug')
-    exit_status = os.system(command)
 
-    with io.open(outfile, 'rb') as fh:
-        if exit_status:
-            raise RuntimeError('pdftops was not able to process your \
-image.\nHere is the full report generated by pdftops: \n\n' + fh.read())
-        else:
+    command = ["pdftops", "-paper", "match", "-level2", pdffile, psfile]
+    verbose.report(command, 'debug')
+    try:
+        with open(outfile, "w") as fout:
+            subprocess.check_call(command,
+                                  stdout=fout, stderr=subprocess.STDOUT)
+    except subprocess.CalledProcessError as exc:
+        with io.open(outfile, 'rb') as fh:
+            raise RuntimeError('pdftops was not able to process your image.\n'
+                               'Here is the full report generated by pdftops: '
+                               '%s\n\n' % fh.read())
+    else:
+        with io.open(outfile, 'rb') as fh:
             verbose.report(fh.read(), 'debug')
     os.remove(outfile)
     os.remove(tmpfile)

tools/subset.py

@@ -28,6 +28,7 @@
 import sys
 import getopt
 import os
+import subprocess
 import struct
 
 def log_namelist(nam, unicode):
@@ -145,7 +146,7 @@ def subset_font_raw(font_in, font_out, unicodes, opts):
     if pe:
         print('Generate("' + font_out + '")', file=pe)
         pe.close()
-        os.system("fontforge -script " + pe_fn)
+        subprocess.call(["fontforge", "-script", pe_fn])
     else:
         font.generate(font_out, flags = flags)
     font.close()