Re: [libvirt] [PATCH 00/75] Drop virAsprintf() in favor of g_strdup_printf()

On 10/22/19 3:57 PM, Michal Privoznik wrote: For future reference and anybody interested, I've made these changes using coccinelle http://coccinelle.lip6.fr/ I've used three semantic patches (aka spatch). The first one was to rename virAsprintfQueit() to virAsprintf(). It is trivial: $ cat virasprintf_rename.spatch @@ @@ -virAsprintfQuiet +virAsprintf Runnig coccinelle is fairly easy now that Jano pushed the macro file [1]: libvirt.git $ spatch --in-place --macro-file scripts/cocci-macro-file.h \ --sp-file virasprintf_rename.spatch --dir . The second spatch is a bit more complicated/verbose: $ cat virasprintf_no_return.spatch @@ expression e1, e2, e3; statement S; @@ -if (virAsprintf(e1, e2, e3) < 0) -S +virAsprintf(e1, e2, e3); @@ expression e1, e2, e3, e4; statement S; @@ -if (virAsprintf(e1, e2, e3, e4) < 0) -S +virAsprintf(e1, e2, e3, e4); [this pattern continues 3 more times, each time new argument is added] It is here that I've encountered first problems. Firstly, my spatch skills are not good enough (obviously), because I had to write several rules - each one for different number of arguments passed to virAsprintf(). But more importantly, I've completely missed joined statements like: if (virAsprintf() < 0 || virAsprintf() < 0) goto cleanup; On the other hand, I was left with only a few places that needed fixing. Coccinelle did 90% of conversion and I needed to do the rest by hand, which is a fair trade off IMO. Finally, the last spatch was used to rewrite code from using virAsprintf() to g_strdup_printf: $ cat g_strdup_printf.spatch @@ expression x; @@ -virAsprintf(&x, +x = g_strdup_printf( ... ); Again, worked perfectly except few places where we did not pass &x but x (which was char **). I've tried to make an spatch for that too but didn't succeed, so I've fixed those places by hand. Michal 1: Thing is, while coccinelle understands C very well, it doesn't quite understand all those __attribute__ and other extensions. Therefore, some macros made it impossible for coccinelle to parse some functions (e.g. g_autofree, g_autoptr and similar) and it did not perform requested change there then.