[gentoo-dev] [PATCH 1/2] python-utils-r1.eclass: Issue more explanatory errors wrt wrong env

[Michał Górny]

The current errors about incorrect call context are cryptic at best.
Replace the inline checks with a single _python_check_EPYTHON function
and provide a verbose explanation how to fix the problem.

Signed-off-by: Michał Górny <mgorny@g.o>
---
 eclass/distutils-r1.eclass    |  2 +-
 eclass/python-utils-r1.eclass | 35 +++++++++++++++++++++++++++--------
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/eclass/distutils-r1.eclass b/eclass/distutils-r1.eclass
index 344aa46b2f94..3286842f0933 100644
--- a/eclass/distutils-r1.eclass
+++ b/eclass/distutils-r1.eclass
@@ -459,7 +459,7 @@ distutils_enable_tests() {
 esetup.py() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	[[ -n ${EPYTHON} ]] || die "EPYTHON unset, invalid call context"
+	_python_check_EPYTHON
 
 	[[ ${BUILD_DIR} ]] && _distutils-r1_create_setup_cfg
 
diff --git a/eclass/python-utils-r1.eclass b/eclass/python-utils-r1.eclass
index 168c767a2eea..fac1fa7facb7 100644
--- a/eclass/python-utils-r1.eclass
+++ b/eclass/python-utils-r1.eclass
@@ -549,6 +549,26 @@ python_get_scriptdir() {
 	echo "${PYTHON_SCRIPTDIR}"
 }
 
+# @FUNCTION: _python_check_EPYTHON
+# @INTERNAL
+# @DESCRIPTION:
+# Verify that EPYTHON is set.  Die with an explanatory error if it
+# is not.
+_python_check_EPYTHON() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	[[ -n ${EPYTHON} ]] && return
+
+	eerror "${FUNCNAME[1]} must be called in a valid Python execution context."
+	eerror "This usually means one of the following:"
+	eerror
+	eerror " 1. inside python_* sub-phase, called via distutils-r1_src* function."
+	eerror " 2. inside a function called via python_foreach_impl."
+	eerror " 3. after a call to python_setup."
+
+	die "${FUNCNAME[1]} must be called in a valid Python execution context"
+}
+
 # @FUNCTION: python_optimize
 # @USAGE: [<directory>...]
 # @DESCRIPTION:
@@ -567,8 +587,7 @@ python_optimize() {
 		die "python_optimize is not to be used in pre/post* phases"
 	fi
 
-	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'
-
+	_python_check_EPYTHON
 	local PYTHON=${PYTHON}
 	[[ ${PYTHON} ]] || _python_export PYTHON
 	[[ -x ${PYTHON} ]] || die "PYTHON (${PYTHON}) is not executable"
@@ -666,7 +685,7 @@ python_doexe() {
 python_newexe() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'
+	_python_check_EPYTHON
 	[[ ${#} -eq 2 ]] || die "Usage: ${FUNCNAME} <path> <new-name>"
 
 	local wrapd=${_PYTHON_SCRIPTROOT:-/usr/bin}
@@ -794,7 +813,7 @@ python_moduleinto() {
 python_domodule() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'
+	_python_check_EPYTHON
 
 	local d
 	if [[ ${_PYTHON_MODULEROOT} == /* ]]; then
@@ -831,7 +850,7 @@ python_domodule() {
 python_doheader() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'
+	_python_check_EPYTHON
 
 	local includedir=$(python_get_includedir)
 	local d=${includedir#${EPREFIX}}
@@ -1022,7 +1041,7 @@ python_is_installed() {
 python_fix_shebang() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	[[ ${EPYTHON} ]] || die "${FUNCNAME}: EPYTHON unset (pkg_setup not called?)"
+	_python_check_EPYTHON
 
 	local force quiet
 	while [[ ${@} ]]; do
@@ -1254,7 +1273,7 @@ build_sphinx() {
 epytest() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	[[ -n ${EPYTHON} ]] || die "EPYTHON unset, invalid call context"
+	_python_check_EPYTHON
 
 	local args=(
 		# verbose progress reporting and tracebacks
@@ -1285,7 +1304,7 @@ epytest() {
 eunittest() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	[[ -n ${EPYTHON} ]] || die "EPYTHON unset, invalid call context"
+	_python_check_EPYTHON
 
 	set -- "${EPYTHON}" -m unittest_or_fail discover -v "${@}"
 
-- 
2.32.0