Re: [PATCH] Makefile: drop GEN_HDRS
- From
Jeff King <peff@peff.net>
- Date
- Dec 16, 2019, 19:20 UTC
- Message-ID
- <20191216192014.GA2678964@coredump.intra.peff.net>
- In-Reply-To
- <xmqqlfrcje1f.fsf@gitster-ct.c.googlers.com>
On Mon, Dec 16, 2019 at 10:55:40AM -0800, Junio C Hamano wrote:
Show 10 quoted lines
> LIB_H could contain command-list.h (and other GENERATED_H files) if > we did this, but dups in dependency does not hurt in general, and I > did not find anything potentially problematic in the existing use of > $(LIB_H) in our Makefile. > > How about doing this as a further clean-up? I am reasonably sure > the status-quo description is correct, but I find the justification > a bit weak (in other words, I do not have a good answer to "who > cares if those that depend on $(LIB_H) are not rebuilt when > command-list.h gets rebuilt?")
Yeah, I don't think there's any change in behavior here, since with the exception of hdr-check, every mention of $(LIB_H) also mentioned $(GENERATED_H). And in the case of hdr-check, we explicitly exclude the only item found in $(GENERATED_H).
But this would enable us to start checking command-list.h. I'm on the fence on whether that's useful or not; the patch below makes it pass, but I'm not sure if that is really turning up any useful problems. I suppose somebody besides help.c could include command-list.h, in which case some of those MAYBE_UNUSED bits could become useful.
I actually wonder if the whole thing would be simpler if command-list.h was a static tracked file with the declarations, and we generated command-list.c with "extern const char *command_list[]", etc.
Show 13 quoted lines
> --- >8 --- > Makefile: include GENERATED_H in LIB_H > > $(LIB_H), which is meant to be the list of header files that can > affect (hence trigger recompilation) the objects that go in > libgit.a, in a directory extracted from a tarball is computed by > running "find \*.h" but instead computed with "ls-files \*.h" in a > working tree managed by a git repository. The former can include > generated header files after a build, and omit them in a clean > state. The latter would not, as generated header files are by > definition not tracked. > > Explicitly add $(GENERATED_H) to $(LIB_H) to make things consistent.
I do think this is slightly simpler to reason about than the existing setup (though see my "should it just be a C file?" above).
Here's the patch that would make hdr-check work:
---
diff --git a/Makefile b/Makefile index 87b68962ed..1eac8e7a7a 100644 --- a/Makefile +++ b/Makefile @@ -2780,7 +2780,7 @@ $(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE .PHONY: sparse $(SP_OBJ) sparse: $(SP_OBJ) -GEN_HDRS := command-list.h unicode-width.h +GEN_HDRS := unicode-width.h EXCEPT_HDRS := $(GEN_HDRS) compat/% xdiff/% ifndef GCRYPT_SHA256 EXCEPT_HDRS += sha256/gcrypt.h diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh index 71158f7d8b..7b0751e3e1 100755 --- a/generate-cmdlist.sh +++ b/generate-cmdlist.sh @@ -48,6 +48,7 @@ define_categories () { define_category_names () { echo echo "/* Category names */" + echo "MAYBE_UNUSED" echo "static const char *category_names[] = {" bit=0 category_list "$1" | @@ -61,6 +62,7 @@ define_category_names () { } print_command_list () { + echo "MAYBE_UNUSED" echo "static struct cmdname_help command_list[] = {" command_list "$1" | @@ -78,6 +80,7 @@ print_command_list () { print_config_list () { cat <<EOF +MAYBE_UNUSED static const char *config_name_list[] = { EOF grep -h '^[a-zA-Z].*\..*::$' Documentation/*config.txt Documentation/config/*.txt | @@ -101,7 +104,8 @@ do shift done -echo "/* Automatically generated by generate-cmdlist.sh */ +echo "#include \"gettext.h\" +/* Automatically generated by generate-cmdlist.sh */ struct cmdname_help { const char *name; const char *help;