all: use die() rather than error(EXIT_FAILURE)

die() has the advantage of being apparent to the compiler
that it doesn't return, which will avoid warnings in some cases,
and possibly generate better code.
* cfg.mk (sc_die_EXIT_FAILURE): A new syntax check rule to
catch any new uses of error (CONSTANT, ...);

1 files changed, 10 insertions, 0 deletions

diff --git a/cfg.mk b/cfg.mk
index 9acb42c34..ece6efa88 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -226,6 +226,16 @@ sc_error_shell_always_quotes:
 	       exit 1; }  \
 	  || :
 
+# Usage of error() with an exit constant, should instead use die(),
+# as that avoids warnings and may generate better code, due to being apparent
+# to the compiler that it doesn't return.
+sc_die_EXIT_FAILURE:
+	@cd $(srcdir)/src && GIT_PAGER= git grep -E \
+	    'error \(.*_(FAILURE|INVALID)' \
+	  && { echo '$(ME): '"Use die() instead of error" 1>&2; \
+	       exit 1; }  \
+	  || :
+
 # Avoid unstyled quoting to internal slots and thus destined for diagnostics
 # as that can leak unescaped control characters to the output, when using
 # the default "literal" quoting style.