2010/7/23 Eric Blake <eblake(a)redhat.com>:
This would have detected the bug in commit 38ad33931 (Aug 09), which
we missed until commit f828ca35 (Jul 10); over 11 months later.
However, on Fedora 13, it also triggers LOTS of warnings from
the libcurl-devel header for one file:
esx/esx_vi.c: In function 'esxVI_CURL_Perform':
esx/esx_vi.c:232: error: logical '&&' with non-zero constant will always
evaluate as true [-Wlogical-op]
esx/esx_vi.c:232: error: logical '&&' with non-zero constant will always
evaluate as true [-Wlogical-op]
esx/esx_vi.c:232: error: logical '&&' with non-zero constant will always
evaluate as true [-Wlogical-op]
...
I figure the gross hack to disable the warnings in the third-party
code, along with the reduction in type-safety in just esx_vi.c,
is worth the improved compiler checking throughout the rest of libvirt.
* acinclude.m4 (--enable-compile-warnings=error): Add
-Wlogical-op.
* src/esx/esx_vi.c (includes): Hack around broken libcurl-devel
header, to avoid compilation warning.
Suggested by Daniel P. Berrange.
---
In response to
https://www.redhat.com/archives/libvir-list/2010-July/msg00497.html
and fixing some long lines while I was at it.
acinclude.m4 | 16 +++++++++++++---
src/esx/esx_vi.c | 10 ++++++++++
2 files changed, 23 insertions(+), 3 deletions(-)
@@ -36,6 +36,16 @@
#include "esx_vi_methods.h"
#include "esx_util.h"
+
+/* XXX "esx_vi.h" includes <curl/curl.h>; as of
+ * libcurl-devel-7.20.1-3.fc13.x86_64, curl ships a version of this
+ * header that #defines several wrapper macros around underlying
+ * functions to add type safety for gcc only. However, these macros
+ * spuriously trip gcc's -Wlogical-op warning. Avoid the warning by
+ * nuking the wrappers; even if it removes some type-check safety. */
+# undef curl_easy_getinfo
+# undef curl_easy_setopt
+
#define VIR_FROM_THIS VIR_FROM_ESX
No need to hack here. We can define CURL_DISABLE_TYPECHECK to disable
those type checks.
Also the warnings are not that spuriously. If you look at
typecheck-gcc.h you'll see that the condition of the if clauses only
depend onto type information. This type information is static at
compile- and runtime, so gcc is correct to warn about them being fixed
true or false.
This also affects the XenAPI driver because it includes curl.h too.
Therefore, I suggest the attached variation of your patch.
Matthias