[gentoo-dev] [PATCH 3/3] llvm.eclass: Fix prepending LLVM path before system paths

[Michał Górny]

Do not prepend LLVM path before system path, in particular before
ccache/distcc paths.  Instead, prepend it before the first LLVM version
found in PATH, or append to the end if no LLVM is found in PATH.

Closes: https://bugs.gentoo.org/627726
Signed-off-by: Michał Górny <mgorny@g.o>
---
 eclass/llvm.eclass   | 25 +++++++++++++++++++++++--
 eclass/tests/llvm.sh | 16 ++++++++--------
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/eclass/llvm.eclass b/eclass/llvm.eclass
index 4f968dc39f87..61b34d4985eb 100644
--- a/eclass/llvm.eclass
+++ b/eclass/llvm.eclass
@@ -198,8 +198,29 @@ llvm_pkg_setup() {
 	debug-print-function ${FUNCNAME} "${@}"
 
 	if [[ ${MERGE_TYPE} != binary ]]; then
-		local llvm_prefix=$(get_llvm_prefix "${LLVM_MAX_SLOT}")
-		export PATH=${llvm_prefix}/bin:${PATH}
+		local llvm_path=$(get_llvm_prefix "${LLVM_MAX_SLOT}")/bin
+		local IFS=:
+		local split_path=( ${PATH} )
+		local new_path=()
+		local x added=
+
+		# prepend new path before first LLVM version found
+		for x in "${split_path[@]}"; do
+			if [[ ${x} == */usr/lib/llvm/*/bin ]]; then
+				if [[ ${x} != ${llvm_path} ]]; then
+					new_path+=( "${llvm_path}" )
+				elif [[ ${added} && ${x} == ${llvm_path} ]]; then
+					# deduplicate
+					continue
+				fi
+				added=1
+			fi
+			new_path+=( "${x}" )
+		done
+		# ...or to the end of PATH
+		[[ ${added} ]] || new_path+=( "${llvm_path}" )
+
+		export PATH=${new_path[*]}
 	fi
 }
 
diff --git a/eclass/tests/llvm.sh b/eclass/tests/llvm.sh
index bb8d5fc998e8..8527d81765dd 100755
--- a/eclass/tests/llvm.sh
+++ b/eclass/tests/llvm.sh
@@ -91,17 +91,17 @@ eindent
 	LLVM_MAX_SLOT=11 \
 	LLVM_INSTALLED_SLOT=1* \
 	PATH=${BASEPATH}:/usr/lib/llvm/11/bin \
-	check_setup_path "/usr/lib/llvm/11/bin:${BASEPATH}:/usr/lib/llvm/11/bin"
+	check_setup_path "${BASEPATH}:/usr/lib/llvm/11/bin"
 
 	LLVM_MAX_SLOT=10 \
 	LLVM_INSTALLED_SLOT=1* \
 	PATH=${BASEPATH}:/usr/lib/llvm/11/bin:/usr/lib/llvm/10/bin \
-	check_setup_path "/usr/lib/llvm/10/bin:${BASEPATH}:/usr/lib/llvm/11/bin:/usr/lib/llvm/10/bin"
+	check_setup_path "${BASEPATH}:/usr/lib/llvm/10/bin:/usr/lib/llvm/11/bin"
 
 	LLVM_MAX_SLOT=11 \
 	LLVM_INSTALLED_SLOT=10 \
 	PATH=${BASEPATH}:/usr/lib/llvm/10/bin \
-	check_setup_path "/usr/lib/llvm/10/bin:${BASEPATH}:/usr/lib/llvm/10/bin"
+	check_setup_path "${BASEPATH}:/usr/lib/llvm/10/bin"
 eoutdent
 
 ebegin "Testing pkg_setup with the other LLVM version in PATH"
@@ -109,12 +109,12 @@ eindent
 	LLVM_MAX_SLOT=11 \
 	LLVM_INSTALLED_SLOT=1* \
 	PATH=${BASEPATH}:/usr/lib/llvm/10/bin \
-	check_setup_path "/usr/lib/llvm/11/bin:${BASEPATH}:/usr/lib/llvm/10/bin"
+	check_setup_path "${BASEPATH}:/usr/lib/llvm/11/bin:/usr/lib/llvm/10/bin"
 
 	LLVM_MAX_SLOT=10 \
 	LLVM_INSTALLED_SLOT=1* \
 	PATH=${BASEPATH}:/usr/lib/llvm/11/bin \
-	check_setup_path "/usr/lib/llvm/10/bin:${BASEPATH}:/usr/lib/llvm/11/bin"
+	check_setup_path "${BASEPATH}:/usr/lib/llvm/10/bin:/usr/lib/llvm/11/bin"
 eoutdent
 
 ebegin "Testing pkg_setup with LLVM missing from PATH"
@@ -122,17 +122,17 @@ eindent
 	LLVM_MAX_SLOT=11 \
 	LLVM_INSTALLED_SLOT=1* \
 	PATH=${BASEPATH} \
-	check_setup_path "/usr/lib/llvm/11/bin:${BASEPATH}"
+	check_setup_path "${BASEPATH}:/usr/lib/llvm/11/bin"
 
 	LLVM_MAX_SLOT=10 \
 	LLVM_INSTALLED_SLOT=1* \
 	PATH=${BASEPATH} \
-	check_setup_path "/usr/lib/llvm/10/bin:${BASEPATH}"
+	check_setup_path "${BASEPATH}:/usr/lib/llvm/10/bin"
 
 	LLVM_MAX_SLOT=11 \
 	LLVM_INSTALLED_SLOT=10 \
 	PATH=${BASEPATH} \
-	check_setup_path "/usr/lib/llvm/10/bin:${BASEPATH}"
+	check_setup_path "${BASEPATH}:/usr/lib/llvm/10/bin"
 eoutdent
 
 texit
-- 
2.26.2