[gentoo-dev] [PATCH 02/12] python-utils-r1.eclass: New python_fix_shebang approach

[James Le Cuirot]

The previous approach would erroneously match foopython. The new
approach requires the match to start the string or be preceeded by a
slash, the only two cases we actually want. It does this with slightly
less code and allows the replacement of whole path strings that would
be problematic when passed to sed. This will be needed when
cross-compiling is addressed.

Signed-off-by: James Le Cuirot <chewi@g.o>
---
 eclass/python-utils-r1.eclass | 78 ++++++++++++++---------------------
 1 file changed, 31 insertions(+), 47 deletions(-)

diff --git a/eclass/python-utils-r1.eclass b/eclass/python-utils-r1.eclass
index da76a755fb34..1eca0764a202 100644
--- a/eclass/python-utils-r1.eclass
+++ b/eclass/python-utils-r1.eclass
@@ -1165,8 +1165,7 @@ python_fix_shebang() {
 		[[ -d ${path} ]] && is_recursive=1
 
 		while IFS= read -r -d '' f; do
-			local shebang i
-			local error= from=
+			local shebang i= error= fix=
 
 			# note: we can't ||die here since read will fail if file
 			# has no newline characters
@@ -1175,65 +1174,56 @@ python_fix_shebang() {
 			# First, check if it's shebang at all...
 			if [[ ${shebang} == '#!'* ]]; then
 				local split_shebang=()
-				read -r -a split_shebang <<<${shebang} || die
+				read -r -a split_shebang <<<${shebang#\#\!} || die
 
 				# Match left-to-right in a loop, to avoid matching random
 				# repetitions like 'python2.7 python2'.
-				for i in "${split_shebang[@]}"; do
-					case "${i}" in
-						*"${EPYTHON}")
+				for i in $(seq 0 $((${#split_shebang[@]} - 1))); do
+					case "/${split_shebang[${i}]}" in
+						*/${EPYTHON})
 							debug-print "${FUNCNAME}: in file ${f#${D%/}}"
 							debug-print "${FUNCNAME}: shebang matches EPYTHON: ${shebang}"
 
 							# Nothing to do, move along.
 							any_correct=1
-							from=${EPYTHON}
+							continue 2
+							;;
+						*/python)
+							fix=1
 							break
 							;;
-						*python|*python[23])
-							debug-print "${FUNCNAME}: in file ${f#${D%/}}"
-							debug-print "${FUNCNAME}: rewriting shebang: ${shebang}"
-
-							if [[ ${i} == *python2 ]]; then
-								from=python2
-								if [[ ! ${force} ]]; then
-									python_is_python3 "${EPYTHON}" && error=1
-								fi
-							elif [[ ${i} == *python3 ]]; then
-								from=python3
-								if [[ ! ${force} ]]; then
-									python_is_python3 "${EPYTHON}" || error=1
-								fi
-							else
-								from=python
+						*/python2)
+							if [[ ! ${force} ]]; then
+								python_is_python3 "${EPYTHON}" && error=1
 							fi
+							fix=1
 							break
 							;;
-						*python[23].[0123456789]|*pypy|*pypy3|*jython[23].[0123456789])
-							# Explicit mismatch.
+						*/python3)
 							if [[ ! ${force} ]]; then
-								error=1
-							else
-								case "${i}" in
-									*python[23].[0123456789])
-										from="python[23].[0123456789]";;
-									*pypy)
-										from="pypy";;
-									*pypy3)
-										from="pypy3";;
-									*jython[23].[0123456789])
-										from="jython[23].[0123456789]";;
-									*)
-										die "${FUNCNAME}: internal error in 2nd pattern match";;
-								esac
+								python_is_python3 "${EPYTHON}" || error=1
 							fi
+							fix=1
+							break
+							;;
+						*/python[2-3].[0-9]|*/pypy|*/pypy3|*/jython[2-3].[0-9])
+							# Explicit mismatch.
+							[[ ! ${force} ]] && error=1
+							fix=1
 							break
 							;;
 					esac
 				done
 			fi
 
-			if [[ ! ${error} && ! ${from} ]]; then
+			if [[ ${fix} ]]; then
+				debug-print "${FUNCNAME}: in file ${f#${D%/}}"
+				debug-print "${FUNCNAME}: rewriting shebang: ${shebang}"
+
+				split_shebang[${i}]=/${split_shebang[${i}]}
+				split_shebang[${i}]=${split_shebang[${i}]%/*}
+				split_shebang[${i}]=${split_shebang[${i}]#/}${split_shebang[${i}]:+/}${EPYTHON}
+			elif [[ ! ${error} ]]; then
 				# Non-Python shebang. Allowed in recursive mode,
 				# disallowed when specifying file explicitly.
 				[[ ${is_recursive} ]] && continue
@@ -1245,13 +1235,7 @@ python_fix_shebang() {
 			fi
 
 			if [[ ! ${error} ]]; then
-				# We either want to match ${from} followed by space
-				# or at end-of-string.
-				if [[ ${shebang} == *${from}" "* ]]; then
-					sed -i -e "1s:${from} :${EPYTHON} :" "${f}" || die
-				else
-					sed -i -e "1s:${from}$:${EPYTHON}:" "${f}" || die
-				fi
+				sed -i -e "1c#\!${split_shebang[*]}" "${f}" || die
 				any_fixed=1
 			else
 				eerror "The file has incompatible shebang:"
-- 
2.19.2