On Thu, Mar 31 2022, Junio C Hamano wrote: [Changed $subject to make this easier to find] > Garrit Franke <garrit@slashdev.space> writes: > >> Clean up includes no longer needed by bisect.c. >> >> Signed-off-by: Garrit Franke <garrit@slashdev.space> >> --- >> bisect.c | 9 --------- >> 1 file changed, 9 deletions(-) >> >> diff --git a/bisect.c b/bisect.c >> index 9e6a2b7f20..e07e2d215d 100644 >> --- a/bisect.c >> +++ b/bisect.c >> @@ -1,21 +1,12 @@ >> -#include "cache.h" > > cf. Documentation/CodingGuidelines > > The first #include must be <git-compat-util.h>, or <cache.h> or > <builtin.h>, which are well known to include <git-compat-util.h> > first. > > Including <git-compat-util.h> indirectly by <config.h> -> > <hashmap.h> -> <hash.h> -> <git-compat-util.h> does not count. Also: Some built-ins don't include builtin.h as they should, a fix (or even basic CI check) for that would be most welcome. git grep -C2 -n -F -e builtin.h -e cache.h -e git-compat-util.h -- builtin I.e. we have this saying a lot of those are redundant: Documentation/CodingGuidelines- - The first #include in C files, except in platform specific compat/ Documentation/CodingGuidelines- implementations, must be either "git-compat-util.h", "cache.h" or Documentation/CodingGuidelines: "builtin.h". You do not have to include more than one of these. But maybe it's not worth it, anyway... >> #include "config.h" >> -#include "commit.h" > > Other headers may indirectly include <commit.h> as their > implementation detail, but what matters is that *we* in this source > file use what <commit.h> gives us ourselves, like the concrete shape > of "struct commit_list". This change is not wanted. > > I'll stop here. There may be truly leftover "unused" includes among > those removed by the remainder of this patch, but I suspect that > some are like <commit.h> above, i.e. we directly use it, and because > we do not want to be broken by some header file's implementation > detail changing, we MUST include it ourselves. > > I think this should give us a useful guideline to sift through the > rest, and an updated patch to remove truly unused ones are very much > welcome. We may actually find some we are not directly including > ourselves but we should (e.g. I do not see <string-list.h> included > by us, but we clearly use structures and functions declared there, > and probably is depending, wrongly, on some header file we include > happens to indirectly include it). ... For anyone interested in pursuing this, I think using the excellent include-what-you-use tool would be a nice start. We could even eventually add it to our CI if the false positive rate isn't bad (I haven't checked much): https://github.com/include-what-you-use/include-what-you-use E.g. in this case (I manually omitted the rest of the output, there's probably a iwyu option to omit it, but I didn't see how do that from skimming the docs): $ sudo apt install iwyu # YMMV $ make bisect.o CC=include-what-you-use CFLAGS="-Xiwyu --verbose=1" 2>&1 | grep -v -E -e '^#include <' -e '^#include "(cache|git-compat-util|gettext)\.h"' CC bisect.o (bisect.h has correct #includes/fwd-decls) bisect.c should add these lines: #include "hash.h" // for oideq, object_id, oidcmp, oidcpy, GIT_... #include "object.h" // for object, repo_clear_commit_marks #include "path.h" // for GIT_PATH_FUNC, git_pathdup #include "pretty.h" // for CMIT_FMT_UNSPECIFIED, format_commit_me... #include "repository.h" // for repository (ptr only), the_repository #include "strbuf.h" // for strbuf_release, strbuf, strbuf_getline_lf #include "string-list.h" // for string_list_append, string_list_clear bisect.c should remove these lines: - #include "hash-lookup.h" // lines 9-9 - struct commit_weight; // lines 76-76 Then if I patch it as: diff --git a/bisect.c b/bisect.c index 9e6a2b7f201..512430e3cc8 100644 --- a/bisect.c +++ b/bisect.c @@ -6,7 +6,6 @@ #include "refs.h" #include "list-objects.h" #include "quote.h" -#include "hash-lookup.h" #include "run-command.h" #include "log-tree.h" #include "bisect.h" @@ -16,6 +15,13 @@ #include "commit-reach.h" #include "object-store.h" #include "dir.h" +#include "hash.h" +#include "object.h" +#include "path.h" +#include "pretty.h" +#include "repository.h" +#include "strbuf.h" +#include "string-list.h" static struct oid_array good_revs; static struct oid_array skipped_revs; It's happier, but probably needs to be told to ignore define_commit_slab() somehow: $ make bisect.o CC=include-what-you-use CFLAGS="-Xiwyu --verbose=1" 2>&1 | grep -v -E -e '^#include <' -e '^#include "(cache|git-compat-util|gettext)\.h"' CC bisect.o (bisect.h has correct #includes/fwd-decls) bisect.c should add these lines: bisect.c should remove these lines: - struct commit_weight; // lines 82-82 That still needs to be massaged a bit, e.g. we should probably omit hash.h and anything else in cache.h and git-compat-util.h. Or maybe not & we should make those headers even lighter. It is rather annoying that changing some of those things leads to a complete re-build, but there's a trade-off there where we probably want things like gettext.h and other used-almost-everywhere headers in included by those. So take all the above with a huge grain of salt. I haven't used iwyu much, but it seems to be something that'll help us go in the direction Junio noted above. I think starting with: make -k git-objs <the CC etc. params above> And tackling the "should remove these lines" issues first would be a good start, e.g. for serve.c it says: serve.c should remove these lines: - #include "cache.h" // lines 1-1 - #include "strvec.h" // lines 6-6 We don't want that first one, but it's right about the second one. It's been orphaned since f0a35c9ce52 (serve: drop "keys" strvec, 2021-09-15), I skimmed some of the rist and they all seem like good suggestions. E.g. lockfile.h for builtin/apply.c, which isn't needed since 6d058c88264 (apply: move lockfile into `apply_state`, 2017-10-05).
