From: "Anthony J. Bentley" <bentley@openbsd.org>
Subject: Re: Poison ccache and sccache
To: Klemens Nanni <kn@openbsd.org>
Cc: ports@openbsd.org
Date: Thu, 10 Sep 2026 04:48:37 -0600

Klemens Nanni writes:
> I'm not convinced we should help the port(er) use ccache(1) directly.
>
> Rather all usage should go through USE_CCACHE, which does warn if the
> package is missing.

USE_CCACHE is a user setting, so ports aren't allowed to toggle it.
The only option within a port is to add ccache to BUILD_DEPENDS or to
disable ccache in the upstream code.

Of course disabling is better, but sometimes there is no knob, so we
patch ccache away. I can imagine a situation where it's too hard to
patch away (I'm thinking of the handful of ports that still use doxygen
despite our best efforts). Avoiding a hidden dep is the most important
thing since it hurts bulks.

> >  # poison some common binaries unless the relevant BUILD_DEPENDS is used
> > +.if empty(_BUILD_DEP:Mdevel/ccache) && \
> > +		empty(_BUILD_DEP:Mdevel/ccache)
>
> Same check twice?

Oops, fixed.

> > +	@printf '#!/bin/sh\n\
> > +		echo "*** $$0 was called without devel/ccache dependency ***" >
> &2\n\
>
> Again, I'd refer to our bsd.port.mk knob and not encourage direct use.

As mentioned, it doesn't make sense to reference our USE_CCACHE here.
This check is for catching a problem in the port whether the porter has
chosen to enable ccache or not.

Here's a better version that encourages disabling ccache first.

--- infrastructure/mk/bsd.port.mk
+++ infrastructure/mk/bsd.port.mk
@@ -452,7 +452,8 @@ CCACHE_DIR ?= ${WRKOBJDIR_${PKGPATH}}/.ccache
 MAKE_ENV += CCACHE_DIR=${CCACHE_DIR} ${CCACHE_ENV}
 CONFIGURE_ENV += CCACHE_DIR=${CCACHE_DIR}
 # scons cleans the environment when calling the compiler
-COMPILER_WRAPPER += env CCACHE_DIR=${CCACHE_DIR} ${CCACHE_ENV} ccache
+COMPILER_WRAPPER += env CCACHE_DIR=${CCACHE_DIR} ${CCACHE_ENV} \
+	${LOCALBASE}/bin/ccache
 .  if !exists(${LOCALBASE}/bin/ccache)
 ERRORS += "Fatal: USE_CCACHE is set, but ccache is not installed."
 .  endif
@@ -2783,6 +2784,12 @@ ${_WRKDIR_COOKIE}:
 	@${_PBUILD} mkdir -p ${WRKDIR} ${WRKDIR}/bin
 	@${_wrap_install_commands}
 # poison some common binaries unless the relevant BUILD_DEPENDS is used
+.if empty(_BUILD_DEP:Mdevel/ccache)
+	@printf '#!/bin/sh\n\
+		echo "*** $$0 was called; disable it or add an explicit dependency ***" >&2\n\
+		exit 1\n' ${_PREDIR} ${WRKDIR}/bin/ccache
+	@${_PBUILD} chmod 555 ${WRKDIR}/bin/ccache
+.endif
 .if empty(_BUILD_DEP:Mdevel/gettext,-tools) && \
 		empty(_BUILD_DEP:Mtextproc/intltool)
 	@printf '#!/bin/sh\n\
@@ -2793,6 +2800,12 @@ ${_WRKDIR_COOKIE}:
 	@${_PBUILD} ln -sf msgfmt ${WRKDIR}/bin/${name}
 .  endfor
 .endif
+.if empty(_BUILD_DEP:Mdevel/sccache)
+	@printf '#!/bin/sh\n\
+		echo "*** $$0 was called; disable it or add an explicit dependency ***" >&2\n\
+		exit 1\n' ${_PREDIR} ${WRKDIR}/bin/sccache
+	@${_PBUILD} chmod 555 ${WRKDIR}/bin/sccache
+.endif
 .if empty(_BUILD_DEP:Mtextproc/asciidoc)
 	@printf '#!/bin/sh\n\
 		echo "*** $$0 was called without textproc/asciidoc dependency ***" >&2\n\