From 412cb2ec1302364aba862b183210249c2ca7d44e Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Thu, 15 Jan 2015 15:20:09 -0800 Subject: [PATCH] CodingGuidelines: clarify C #include rules Even though "advice.h" includes "git-compat-util.h", it is not sensible to have it as the first #include and indirectly satisify the "You must give git-compat-util.h a clean environment to set up feature test macros before including any of the system headers are included", which is the real requirement. Because: - A command that interacts with the object store, config subsystem, the index, or the working tree cannot do anything without using what is declared in "cache.h"; - A built-in command must be declared in "builtin.h", so anything in builtin/*.c must include it; - These two headers both include "git-compat-util.h" as the first thing; and - Almost all our *.c files (outside compat/ and borrowed files in xdiff/) need some Git-ness from "cache.h" to do something Git-ish. let's explicitly specify that one of these three header files must be the first thing that is included. Any of our *.c file should include the header file that directly declares what it uses, instead of relying on the fact that some *.h file it includes happens to include another *.h file that declares the necessary function or type. Spell it out as another guideline item. Helped-by: Jeff King Signed-off-by: Junio C Hamano --- Documentation/CodingGuidelines | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines index 4d90c77c7b..ae8b42f3be 100644 --- a/Documentation/CodingGuidelines +++ b/Documentation/CodingGuidelines @@ -328,9 +328,14 @@ For C programs: - When you come up with an API, document it. - - The first #include in C files, except in platform specific - compat/ implementations, should be git-compat-util.h or another - header file that includes it, such as cache.h or builtin.h. + - The first #include in C files, except in platform specific compat/ + implementations, must be either "git-compat-util.h", "cache.h" or + "builtin.h". You do not have to include more than one of these. + + - A C file must directly include the header files that declare the + functions and the types it uses, except for the functions and types + that are made available to it by including one of the header files + it must include by the previous rule. - If you are planning a new command, consider writing it in shell or perl first, so that changes in semantics can be easily