D8330: cext: move more variable declarations to the top of the block for C89 support

[mharbison72 (Matt Harbison)]

mharbison72 created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  These instances aren't compiled on Windows, so they don't matter much.  But they
  do get flagged by `-Werror=declaration-after-statement` in the next patch.
  
  setup: build C extensions with -Werror=declaration-after-statement
  
  MSVC 2008 still needs declarations at the top of the scope.  I added it to the
  3rd party code too in case somebody vendors a new version with a problem-
  they'll get an early warning.  Clang seems to ignore this (at least on 10.14
  with Xcode 10), and gcc 7.4 will error out as desired on Ubuntu 18.04.  Thanks
  to Yuya for remembering the name of the option.

REPOSITORY
  rHG Mercurial

BRANCH
  default

REVISION DETAIL
  https://phab.mercurial-scm.org/D8330

AFFECTED FILES
  mercurial/cext/osutil.c
  setup.py

CHANGE DETAILS

diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -1268,6 +1268,12 @@
 ]
 common_include_dirs = ['mercurial']
 
+common_cflags = []
+
+# MSVC 2008 still needs declarations at the top of the scope.
+if os.name != 'nt':
+    common_cflags = ['-Werror=declaration-after-statement']
+
 osutil_cflags = []
 osutil_ldflags = []
 
@@ -1441,18 +1447,21 @@
         'mercurial.cext.base85',
         ['mercurial/cext/base85.c'],
         include_dirs=common_include_dirs,
+        extra_compile_args=common_cflags,
         depends=common_depends,
     ),
     Extension(
         'mercurial.cext.bdiff',
         ['mercurial/bdiff.c', 'mercurial/cext/bdiff.c'] + xdiff_srcs,
         include_dirs=common_include_dirs,
+        extra_compile_args=common_cflags,
         depends=common_depends + ['mercurial/bdiff.h'] + xdiff_headers,
     ),
     Extension(
         'mercurial.cext.mpatch',
         ['mercurial/mpatch.c', 'mercurial/cext/mpatch.c'],
         include_dirs=common_include_dirs,
+        extra_compile_args=common_cflags,
         depends=common_depends,
     ),
     Extension(
@@ -1466,6 +1475,7 @@
             'mercurial/cext/revlog.c',
         ],
         include_dirs=common_include_dirs,
+        extra_compile_args=common_cflags,
         depends=common_depends
         + ['mercurial/cext/charencode.h', 'mercurial/cext/revlog.h',],
     ),
@@ -1473,7 +1483,7 @@
         'mercurial.cext.osutil',
         ['mercurial/cext/osutil.c'],
         include_dirs=common_include_dirs,
-        extra_compile_args=osutil_cflags,
+        extra_compile_args=common_cflags + osutil_cflags,
         extra_link_args=osutil_ldflags,
         depends=common_depends,
     ),
@@ -1482,6 +1492,7 @@
         [
             'mercurial/thirdparty/zope/interface/_zope_interface_coptimizations.c',
         ],
+        extra_compile_args=common_cflags,
     ),
     Extension(
         'mercurial.thirdparty.sha1dc',
@@ -1490,9 +1501,12 @@
             'mercurial/thirdparty/sha1dc/lib/sha1.c',
             'mercurial/thirdparty/sha1dc/lib/ubc_check.c',
         ],
+        extra_compile_args=common_cflags,
     ),
     Extension(
-        'hgext.fsmonitor.pywatchman.bser', ['hgext/fsmonitor/pywatchman/bser.c']
+        'hgext.fsmonitor.pywatchman.bser',
+        ['hgext/fsmonitor/pywatchman/bser.c'],
+        extra_compile_args=common_cflags,
     ),
     RustStandaloneExtension(
         'mercurial.rustext', 'hg-cpython', 'librusthg', py3_features='python3'
@@ -1503,11 +1517,11 @@
 sys.path.insert(0, 'contrib/python-zstandard')
 import setup_zstd
 
-extmodules.append(
-    setup_zstd.get_c_extension(
-        name='mercurial.zstd', root=os.path.abspath(os.path.dirname(__file__))
-    )
+zstd = setup_zstd.get_c_extension(
+    name='mercurial.zstd', root=os.path.abspath(os.path.dirname(__file__))
 )
+zstd.extra_compile_args += common_cflags
+extmodules.append(zstd)
 
 try:
     from distutils import cygwinccompiler
diff --git a/mercurial/cext/osutil.c b/mercurial/cext/osutil.c
--- a/mercurial/cext/osutil.c
+++ b/mercurial/cext/osutil.c
@@ -810,9 +810,10 @@
 			/* Check the memory we can use. Typically, argv[i] and
 			 * argv[i + 1] are continuous. */
 			for (i = 0; i < argc; ++i) {
+				size_t len;
 				if (argv[i] > argvend || argv[i] < argvstart)
 					break; /* not continuous */
-				size_t len = strlen(argv[i]);
+				len = strlen(argv[i]);
 				argvend = argv[i] + len + 1 /* '\0' */;
 			}
 			if (argvend > argvstart) /* sanity check */
@@ -1170,9 +1171,9 @@
 {
 	int sig = 0;
 	int r;
+	sigset_t set;
 	if (!PyArg_ParseTuple(args, "i", &sig))
 		return NULL;
-	sigset_t set;
 	r = sigemptyset(&set);
 	if (r != 0)
 		return PyErr_SetFromErrno(PyExc_OSError);



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