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Fix a couple of compilation warnings when building with clang #520

Merged
merged 5 commits into from
Nov 6, 2024
Merged

Fix a couple of compilation warnings when building with clang #520

merged 5 commits into from
Nov 6, 2024
+57 −46

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mrc0mmand
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@mrc0mmand mrc0mmand commented Nov 4, 2024 •
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There's still a bunch of warnings caused by -Wdeprecated-declarations, but these can be easily suppressed by -Dc_args=-Wno-deprecated-declarations for now.

This PR also tweaks the CI jobs to build with -Werror, so we should be able to catch these kind of issues a bit earlier in the future.

@mrc0mmand
Add a missing block inside switch statement
ffa6882 
Declaring variables inside switch statement requires a new block (at
least before the C23 extensions were introduced):

$ CC=clang meson build --werror -Dc_args=-Wno-deprecated-declarations
...
$ ninja -C build
ninja: Entering directory `build'
[24/84] Generating glib marshaller header src/polkitagent/polkitagentmarshal_h
INFO: Reading ../src/polkitagent/polkitagentmarshal.list...
[25/84] Generating glib marshaller source src/polkitagent/polkitagentmarshal_c
INFO: Reading ../src/polkitagent/polkitagentmarshal.list...
[53/84] Compiling C object src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendactionpool.c.o
FAILED: src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendactionpool.c.o
clang -Isrc/polkitbackend/libpolkit-backend-1.a.p -Isrc/polkitbackend -I../src/polkitbackend -I. -I.. -Isrc -I../src -Isrc/polkit -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/sysprof-6 -I/usr/include/gio-unix-2.0 -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Werror -std=c99 -O2 -g -D_GNU_SOURCE -include config.h -Waggregate-return -Wdeclaration-after-statement -Wformat=2 -Wimplicit-function-declaration -Winit-self -Wmissing-declarations -Wmissing-include-dirs -Wmissing-prototypes -Wstrict-prototypes -Wno-format-y2k -Wno-declaration-after-statement -Wno-deprecated-declarations -fPIC -pthread -DWITH_GZFILEOP -D_POLKIT_COMPILATION -D_POLKIT_BACKEND_COMPILATION '-DPACKAGE_DATA_DIR="/usr/share"' '-DPACKAGE_SYSCONF_DIR="/etc"' -MD -MQ src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendactionpool.c.o -MF src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendactionpool.c.o.d -o src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendactionpool.c.o -c ../src/polkitbackend/polkitbackendactionpool.c
../src/polkitbackend/polkitbackendactionpool.c:264:7: error: label followed by a declaration is a C23 extension [-Werror,-Wc23-extensions]
  264 |       const gchar **dir_names = (const gchar**) g_value_get_boxed (value);
      |       ^
1 error generated.

Follow-up for 9958c25.
@mrc0mmand
Use GNU C's "format" function attribute where appropriate
b0e2d47 
Which allows correct type-checking during compilation and avoids errors
when building with clang + -Werror:

[58/71] Compiling C object src/programs/pkexec.p/pkexec.c.o
FAILED: src/programs/pkexec.p/pkexec.c.o
clang -Isrc/programs/pkexec.p -Isrc/programs -I../src/programs -I. -I.. -Isrc/polkitagent -I../src/polkitagent -Isrc -I../src -Isrc/polkit -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/sysprof-6 -I/usr/include/gio-unix-2.0 -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Werror -std=c99 -O2 -g -D_GNU_SOURCE -include config.h -Waggregate-return -Wdeclaration-after-statement -Wformat=2 -Wimplicit-function-declaration -Winit-self -Wmissing-declarations -Wmissing-include-dirs -Wmissing-prototypes -Wstrict-prototypes -Wno-format-y2k -Wno-declaration-after-statement -Wno-deprecated-declarations -pthread -DWITH_GZFILEOP -MD -MQ src/programs/pkexec.p/pkexec.c.o -MF src/programs/pkexec.p/pkexec.c.o.d -o src/programs/pkexec.p/pkexec.c.o -c ../src/programs/pkexec.c
../src/programs/pkexec.c:109:25: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
  109 |   s = g_strdup_vprintf (format, var_args);
      |                         ^~~~~~
1 error generated.
[59/71] Compiling C object src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendauthority.c.o
FAILED: src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendauthority.c.o
clang -Isrc/polkitbackend/libpolkit-backend-1.a.p -Isrc/polkitbackend -I../src/polkitbackend -I. -I.. -Isrc -I../src -Isrc/polkit -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/sysprof-6 -I/usr/include/gio-unix-2.0 -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Werror -std=c99 -O2 -g -D_GNU_SOURCE -include config.h -Waggregate-return -Wdeclaration-after-statement -Wformat=2 -Wimplicit-function-declaration -Winit-self -Wmissing-declarations -Wmissing-include-dirs -Wmissing-prototypes -Wstrict-prototypes -Wno-format-y2k -Wno-declaration-after-statement -Wno-deprecated-declarations -fPIC -pthread -DWITH_GZFILEOP -D_POLKIT_COMPILATION -D_POLKIT_BACKEND_COMPILATION '-DPACKAGE_DATA_DIR="/usr/share"' '-DPACKAGE_SYSCONF_DIR="/etc"' -MD -MQ src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendauthority.c.o -MF src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendauthority.c.o.d -o src/polkitbackend/libpolkit-backend-1.a.p/polkitbackendauthority.c.o -c ../src/polkitbackend/polkitbackendauthority.c
../src/polkitbackend/polkitbackendauthority.c:1721:31: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
 1721 |   message = g_strdup_vprintf (format, var_args);
      |                               ^~~~~~
1 error generated.
@mrc0mmand mrc0mmand changed the title Fix a couple of compilationq warnings when building with clang Fix a couple of compilation warnings when building with clang Nov 4, 2024
@mrc0mmand mrc0mmand force-pushed the fix-clang-warnings branch 3 times, most recently from 305b3cd to f2e7683 Compare November 4, 2024 13:46
@mrc0mmand
Explicitly discard unused results where necessary
473df4b 
setre*id() functions are declared with `warn_unused_result` which makes
them emit a warning when their result is unused. This warning can be
suppressed by using (void) cast in clang, so do this where appropriate.
As gcc doesn't support this, disable the warning completely when gcc is
used.

See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425
@mrc0mmand
ci: build with -Werror
2282000 
Suppress the outstanding -Wdeprecated-declarations warnings for now, so
we don't miss real issues in the future.
@mrc0mmand
ci: drop outdated TODO items
a3c8ade 
These were fixed by dropping mocklibc.
@mrc0mmand mrc0mmand mentioned this pull request Nov 4, 2024
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@evverx
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evverx commented Nov 4, 2024

I think it would be great if it was possible to bring back clang in https://packit.dev/posts/openscanhub-prototype to be able to see all the clang warnings fixed in PRs (when -Werror isn't an option). As far as I can remember it was discussed somewhere but I think clang was turned off to reduce the number of false positives in projects using cleanup attributes.

@jrybar-rh jrybar-rh merged commit fdf9172 into polkit-org:main Nov 6, 2024
33 checks passed
@mrc0mmand mrc0mmand deleted the fix-clang-warnings branch November 6, 2024 16:10
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@mrc0mmand @evverx @jrybar-rh