On 06.06.2018 19:32, Daniel P. Berrangé wrote:
> There are two useful macros that can be defined before including
> glib.h that are related to the min required glib version
>
> - GLIB_VERSION_MIN_REQUIRED
>
> When this is defined, if code uses an API that was deprecated
> in this version, or older, a compiler warning will be emitted.
> This alerts maintainers to update their code to whatever new
> replacement API is now recommended best practice.
>
> - GLIB_VERSION_MAX_ALLOWED
>
> When this is defined, if code uses an API that was introduced
> in a version that is newer than the declared version, a compiler
> warning will be emitted. This alerts maintainers if new code
> accidentally uses functionality that won't be available on some
> supported platforms.
>
> The GLIB_VERSION_MAX_ALLOWED constant makes it a bit harder to opt
> in to using specific new APIs with a GLIB_CHECK_VERSION conditional.
> To workaround this Pragmas can be used to temporarily turn off the
> -Wdeprecated-declarations compiler warning, while a static inline
> compat function is implemented. This workaround is illustrated with the
> implementation of the g_strv_contains method to satisfy the test suite.
I wonder whether that's a little bit too much magic already. We could
also set GLIB_VERSION_MAX_ALLOWED to the version where we've already got
the work-arounds in place (i.e. to 2.44 here). If we introduce
additional code that uses other new functions from 2.41 - 2.44, this
should also be caught by the patchew CI builders?
> Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
> ---
> include/glib-compat.h | 67 ++++++++++++++++++++++++
> tests/docker/dockerfiles/centos6.docker | 30 -----------
> tests/docker/dockerfiles/min-glib.docker | 8 ---
The docker files are not directly related to this patch, are they? If
they are, please mention it in the patch description. If not, please
move this to a separate patch (or maybe into patch 1).
> tests/test-qga.c | 2 -
> 4 files changed, 67 insertions(+), 40 deletions(-)
> delete mode 100644 tests/docker/dockerfiles/centos6.docker
> delete mode 100644 tests/docker/dockerfiles/min-glib.docker
>
> diff --git a/include/glib-compat.h b/include/glib-compat.h
> index 3b340ab33c..cfc3cba751 100644
> --- a/include/glib-compat.h
> +++ b/include/glib-compat.h
> @@ -16,8 +16,73 @@
> #ifndef QEMU_GLIB_COMPAT_H
> #define QEMU_GLIB_COMPAT_H
>
> +/* Ask for warnings for anything that was marked deprecated in
> + * the defined version, or before. It is a candidate for rewrite.
> + */
> +#define GLIB_VERSION_MIN_REQUIRED GLIB_VERSION_2_40
> +
> +/* Ask for warnings if code tries to use function that did not
> + * exist in the defined version. These risk breaking builds
> + */
> +#define GLIB_VERSION_MAX_ALLOWED GLIB_VERSION_2_40
> +
> +_Pragma("GCC diagnostic push")
> +_Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
Why not "#pragma" ? I think that's a little bit more common?
Thomas
