Replace ENOENT errno checks with Python 3 FileNotFoundError

The error is more specific and self documenting.

This removes the last use of sphinx.util.osutil.ENOENT, so it is now
deprecated for removal. sphinx.util.osutil.EEXIST was already unused so
that is deprecated as well.

CHANGES

@@ -66,6 +66,8 @@ Deprecated
 * ``sphinx.util.force_decode()``
 * ``sphinx.util.get_matching_docs()``
 * ``sphinx.util.inspect.Parameter``
+* ``sphinx.util.osutil.EEXIST``
+* ``sphinx.util.osutil.ENOENT``
 * ``sphinx.util.osutil.walk()``
 * ``sphinx.util.PeekableIterator``
 * ``sphinx.util.pycompat.u``

doc/extdev/index.rst

@@ -207,6 +207,16 @@ The following is a list of deprecated interfaces.
      - 3.0
      - N/A
 
+   * - ``sphinx.util.osutil.EEXIST``
+     - 2.0
+     - 4.0
+     - ``errno.EEXIST`` or ``FileExistsError``
+
+   * - ``sphinx.util.osutil.ENOENT``
+     - 2.0
+     - 4.0
+     - ``errno.ENOENT`` or ``FileNotFoundError``
+
    * - ``sphinx.util.osutil.walk()``
      - 2.0
      - 4.0

sphinx/ext/graphviz.py

@@ -28,7 +28,7 @@ from sphinx.util.docutils import SphinxDirective
 from sphinx.util.fileutil import copy_asset
 from sphinx.util.i18n import search_image_for_language
 from sphinx.util.nodes import set_source_info
-from sphinx.util.osutil import ensuredir, ENOENT, EPIPE, EINVAL
+from sphinx.util.osutil import ensuredir, EPIPE, EINVAL
 
 if False:
     # For type annotation
@@ -247,9 +247,7 @@ def render_dot(self, code, options, format, prefix='graphviz'):
         dot_args.extend(['-Tcmapx', '-o%s.map' % outfn])
     try:
         p = Popen(dot_args, stdout=PIPE, stdin=PIPE, stderr=PIPE, cwd=cwd)
-    except OSError as err:
-        if err.errno != ENOENT:   # No such file or directory
-            raise
+    except FileNotFoundError:
         logger.warning(__('dot command %r cannot be run (needed for graphviz '
                           'output), check the graphviz_dot setting'), graphviz_dot)
         if not hasattr(self.builder, '_graphviz_warned_dot'):

sphinx/ext/imgconverter.py

@@ -15,7 +15,7 @@ from sphinx.errors import ExtensionError
 from sphinx.locale import __
 from sphinx.transforms.post_transforms.images import ImageConverter
 from sphinx.util import logging
-from sphinx.util.osutil import ENOENT, EPIPE, EINVAL
+from sphinx.util.osutil import EPIPE, EINVAL
 
 if False:
     # For type annotation
@@ -75,9 +75,7 @@ class ImagemagickConverter(ImageConverter):
                     [_from, _to])
             logger.debug('Invoking %r ...', args)
             p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        except OSError as err:
-            if err.errno != ENOENT:  # No such file or directory
-                raise
+        except FileNotFoundError:
             logger.warning(__('convert command %r cannot be run.'
                               'check the image_converter setting'),
                            self.config.image_converter)

sphinx/ext/imgmath.py

@@ -25,7 +25,7 @@ from sphinx.errors import SphinxError
 from sphinx.locale import _, __
 from sphinx.util import logging
 from sphinx.util.math import get_node_equation_number, wrap_displaymath
-from sphinx.util.osutil import ensuredir, ENOENT, cd
+from sphinx.util.osutil import ensuredir, cd
 from sphinx.util.png import read_png_depth, write_png_depth
 from sphinx.util.pycompat import sys_encoding
 
@@ -137,9 +137,7 @@ def compile_math(latex, builder):
     with cd(tempdir):
         try:
             p = Popen(command, stdout=PIPE, stderr=PIPE)
-        except OSError as err:
-            if err.errno != ENOENT:   # No such file or directory
-                raise
+        except FileNotFoundError:
             logger.warning(__('LaTeX command %r cannot be run (needed for math '
                               'display), check the imgmath_latex setting'),
                            builder.config.imgmath_latex)
@@ -157,9 +155,7 @@ def convert_dvi_to_image(command, name):
     """Convert DVI file to specific image format."""
     try:
         p = Popen(command, stdout=PIPE, stderr=PIPE)
-    except OSError as err:
-        if err.errno != ENOENT:   # No such file or directory
-            raise
+    except FileNotFoundError:
         logger.warning(__('%s command %r cannot be run (needed for math '
                           'display), check the imgmath_%s setting'),
                        name, command[0], name)

sphinx/util/osutil.py

@@ -30,8 +30,8 @@ if False:
     from typing import Any, Iterator, List, Tuple, Union  # NOQA
 
 # Errnos that we need.
-EEXIST = getattr(errno, 'EEXIST', 0)
-ENOENT = getattr(errno, 'ENOENT', 0)
+EEXIST = getattr(errno, 'EEXIST', 0)  # RemovedInSphinx40Warning
+ENOENT = getattr(errno, 'ENOENT', 0)  # RemovedInSphinx40Warning
 EPIPE = getattr(errno, 'EPIPE', 0)
 EINVAL = getattr(errno, 'EINVAL', 0)
 

tests/test_ext_math.py

@@ -23,12 +23,10 @@ from sphinx.testing.util import assert_node
 def has_binary(binary):
     try:
         subprocess.check_output([binary])
-    except OSError as e:
-        if e.errno == errno.ENOENT:
-            # handle file not found error.
-            return False
-        else:
-            return True
+    except FileNotFoundError:
+        return False
+    except OSError:
+        pass
     return True