various python neatness cleanups

All changes were created by running

"pyupgrade --py3-only --keep-percent-format"

and committing the results. I have not touched string formatting for
now.

- use set literals
- simplify .format() parameter naming
- remove __future__
- remove default "r" mode for open()
- use OSError rather than compatibility aliases
- remove stray parentheses in function(generator) scopes

2 files changed, 2 insertions, 2 deletions

diff --git a/mesonbuild/scripts/meson_exe.py b/mesonbuild/scripts/meson_exe.py
index 27db144..d44280f 100644
--- a/mesonbuild/scripts/meson_exe.py
+++ b/mesonbuild/scripts/meson_exe.py
@@ -82,7 +82,7 @@ def run_exe(exe: ExecutableSerialisation, extra_env: T.Optional[dict] = None) ->
         try:
             with open(exe.capture, 'rb') as cur:
                 skip_write = cur.read() == stdout
-        except IOError:
+        except OSError:
             pass
         if not skip_write:
             with open(exe.capture, 'wb') as output:
diff --git a/mesonbuild/scripts/symbolextractor.py b/mesonbuild/scripts/symbolextractor.py
index 30065cc..e80d9c2fac 100644
--- a/mesonbuild/scripts/symbolextractor.py
+++ b/mesonbuild/scripts/symbolextractor.py
@@ -43,7 +43,7 @@ def dummy_syms(outfilename: str) -> None:
 
 def write_if_changed(text: str, outfilename: str) -> None:
     try:
-        with open(outfilename, 'r') as f:
+        with open(outfilename) as f:
             oldtext = f.read()
         if text == oldtext:
             return