git: ab0c68ba4ae3 - main - Emit an error when we seen absolute paths to .o files

[Alex Richardson]

The branch main has been updated by arichardson:

URL: https://cgit.FreeBSD.org/src/commit/?id=ab0c68ba4ae37cb83d15e64ce2a33375135ae750

commit ab0c68ba4ae37cb83d15e64ce2a33375135ae750
Author:     Alex Richardson <arichardson at FreeBSD.org>
AuthorDate: 2021-06-21 13:58:01 +0000
Commit:     Alex Richardson <arichardson at FreeBSD.org>
CommitDate: 2021-06-21 15:13:54 +0000

    Emit an error when we seen absolute paths to .o files
    
    This is usually an error caused by using an absolute path in SRCS. This
    happened to me in 83c20b8a2da0 due to changing LDADD to SRCS.
    I did not notice that this had created a .o file inside the source tree
    since .gitignore contains "*.o" and therefore git did not report any
    changes.
    
    Adding this warning message to bsd.lib.mk/bsd.prog.mk should prevent
    issues like this in the future.
    
    There was exactly one case of an absolute OBJS path in the current source
    tree but that was removed in e713d3a013882893fceb84dd14569052271497a9.
    
    Reviewed By:    emaste (earlier version), imp
    Differential Revision: https://reviews.freebsd.org/D28467
---
 share/mk/bsd.dep.mk | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/share/mk/bsd.dep.mk b/share/mk/bsd.dep.mk
index a63b9e46deca..b8dc59d52543 100644
--- a/share/mk/bsd.dep.mk
+++ b/share/mk/bsd.dep.mk
@@ -192,6 +192,17 @@ DEPEND_MP?=	-MP
 # avoid collisions.
 DEPEND_FILTER=	C,/,_,g
 .if !empty(OBJS)
+.if !defined(_ALLOW_ABSOLUTE_OBJ_PATH) && ${OBJS:M/*}
+# Absolute paths to OBJS should be an error inside ${SRCTOP}, but some users
+# might be relying on this feature, so add an opt-out mechanism.
+.if defined(SRCTOP) && ${OBJS:M${SRCTOP}*}
+.error "$$OBJS inside $$SRCTOP not allowed: ${OBJS:M${SRCTOP}*}"
+.elif ${OBJS:N${_ABSOLUTE_PATH_OBJS}:M/*}
+.error "$$OBJS absolute path not allowed: ${OBJS:N${_ABSOLUTE_PATH_OBJS}:M/*}. \
+    If this is intended, add them to _ABSOLUTE_PATH_OBJS to silence this error\
+    or define _ALLOW_ABSOLUTE_OBJ_PATH to disable this diagnostic."
+.endif
+.endif
 DEPENDOBJS+=	${OBJS}
 .else
 DEPENDSRCS+=	${SRCS:M*.[cSC]} ${SRCS:M*.cxx} ${SRCS:M*.cpp} ${SRCS:M*.cc}