[gentoo-commits] proj/portage:master commit in: bin/

["Sam James" <sam@gentoo.org>]

commit:     5f37c8f1fa5261c6ac81ef89bd1276ac0e77f5c6
Author:     Kerin Millar <kfm <AT> plushkava <DOT> net>
AuthorDate: Fri Jul 25 14:22:09 2025 +0000
Commit:     Sam James <sam <AT> gentoo <DOT> org>
CommitDate: Mon Aug 25 09:51:31 2025 +0000
URL:        https://gitweb.gentoo.org/proj/portage.git/commit/?id=5f37c8f1

ebuild.sh: require bash-4.4 and improve __check_bash_version()

As of the time of writing, portage makes use of features that were
introduced by bash-4.4 and, therefore, cannot run correctly with any
older version. However, the __check_bash_version() function does not
currently enforce this requirement.

Address this issue by specifying the minimum required version
independently of the shell compatibility level. The minimum required
version is initially defined as 4.4 but is raised to 5.0 in the event
that the currently effective EAPI requires it (as EAPI 8 does). As is
depicted beneath, the diagnostic messages make this distinction clear.

 * ERROR: sys-apps/portage-9999::gentoo failed (pretend phase):
 *   Portage requires >=bash-4.4 but only 4.3 was found

 * ERROR: sys-apps/portage-9999::gentoo failed (pretend phase):
 *   EAPI 8 requires >=bash-5.0 but only 4.4 was found

Further, apply some minor improvements to the function at large. These
improvements are described herewith.

Remove the comment preceding the function declaration, for it does not
describe its behaviour accurately and is of questionable value.

Clean up the version test by employing an explicit arithmetic context.

Refrain from using the shopt builtin to set the compatibility level.
There is no longer any need to set the compatibility level other than by
assigning to the 'BASH_COMPAT' variable.

Rewrite the remaining commentary so as to employ a more formal tone and
be more informative, without being unduly verbose. Incorporate links to
supporting documentation and associated bug reports, where appropriate.

Attempt to disable the 'patsub_replacement' and 'globskipdots' shell
options on an unconditional basis while simply muting STDERR for the
benefit of bash releases prior to 5.2. As the preceding comment states,
it may become necessary to disable these options on a conditional basis
for a future EAPI. For now, no such logic is required.

See-also: 59b81ecda599e9fbf4084e4595f1fa96c32a9fc1
Signed-off-by: Kerin Millar <kfm <AT> plushkava.net>
Signed-off-by: Sam James <sam <AT> gentoo.org>

 bin/ebuild.sh | 95 +++++++++++++++++++++++++++++++----------------------------
 1 file changed, 50 insertions(+), 45 deletions(-)

diff --git a/bin/ebuild.sh b/bin/ebuild.sh
index 593c18ef5a..12adee68b4 100755
--- a/bin/ebuild.sh
+++ b/bin/ebuild.sh
@@ -12,60 +12,65 @@ declare -F ___in_portage_iuse >/dev/null && export -n -f ___in_portage_iuse
 
 source "${PORTAGE_BIN_PATH:?}/isolated-functions.sh" || exit
 
-# Set up the bash version compatibility level.  This does not disable
-# features when running with a newer version, but makes it so that when
-# bash changes behavior in an incompatible way, the older behavior is
-# used instead.
 __check_bash_version() {
-	# Figure out which min version of bash we require.
-	# Adjust patsub_replacement/globskipdots logic below on new EAPI!
-	local maj min
-	if ___eapi_bash_3_2 ; then
-		maj=3 min=2
-	elif ___eapi_bash_4_2 ; then
-		maj=4 min=2
-	elif ___eapi_bash_5_0 ; then
-		maj=5 min=0
-	elif ___eapi_bash_5_2 ; then
-		maj=5 min=2
-	else
-		return
-	fi
+	local IFS compat_maj compat_min dependent maj min
+
+	# Portage uses features that are only available in >=bash-4.4.
+	dependent="Portage"
+	maj=4
+	min=4
 
-	# Make sure the active bash is sane.
-	if [[ ${BASH_VERSINFO[0]} -lt ${maj} ]] ||
-	   [[ ${BASH_VERSINFO[0]} -eq ${maj} && ${BASH_VERSINFO[1]} -lt ${min} ]] ; then
-		die "EAPI=\"${EAPI}\" requires >=bash-${maj}.${min}, but bash-${BASH_VERSION} found"
+	# Based on the value of EAPI, determine which shell compatibility level
+	# to activate. Further, raise the minimum required version if needs be.
+	#
+	# https://projects.gentoo.org/pms/8/pms.html#x1-580006
+	if ___eapi_bash_3_2; then
+		compat_maj=3
+		compat_min=2
+	elif ___eapi_bash_4_2; then
+		compat_maj=4
+		compat_min=2
+	elif ___eapi_bash_5_0; then
+		dependent="EAPI ${EAPI}"
+		(( compat_maj = maj = 5 ))
+		(( compat_min = min = 0 ))
+	elif ___eapi_bash_5_2; then
+		dependent="EAPI ${EAPI}"
+		(( compat_maj = maj = 5 ))
+		(( compat_min = min = 2 ))
 	fi
 
-	# Set the compat level in case things change with newer ones.  We must not
-	# export this into the env otherwise we might break  other shell scripts we
-	# execute (e.g. ones in /usr/bin).
-	BASH_COMPAT="${maj}.${min}"
-
-	# The variable above is new to bash-4.3.  For older versions, we have to use
-	# a compat knob.  Further, the compat knob only exists with older versions
-	# (e.g. bash-4.3 has compat42 but not compat43).  This means we only need to
-	# turn the knob with older EAPIs, and only when running newer bash versions:
-	# there is no bash-3.3 (it went 3.2 to 4.0), and when requiring bash-4.2, the
-	# var works with bash-4.3+, and you don't need to set compat to 4.2 when you
-	# are already running 4.2.
-	if ___eapi_bash_3_2 && [[ ${BASH_VERSINFO[0]} -gt 3 ]] ; then
-		shopt -s compat32
+	# Ensure that the minimum required version is satisfied.
+	if (( BASH_VERSINFO[0] < maj
+		|| (BASH_VERSINFO[0] == maj && BASH_VERSINFO[1] < min) ))
+	then
+		IFS=.
+		die "${dependent} requires >=bash-${maj}.${min} but only ${BASH_VERSINFO[*]:0:2} was found"
 	fi
 
-	# patsub_replacement and globskipdots are new options in bash-5.2 that are also default-on
-	# in that release. The default value is not gated by BASH_COMPAT (see bug #881383),
-	# hence we need to disable it for older Bashes to avoid behaviour changes in ebuilds
-	# and eclasses.
+	# Activate the selected shell compatibility level, if any. The
+	# BASH_COMPAT variable must never be exported, otherwise it will affect
+	# all bash scripts executed as subprocesses. The following document
+	# explains the behaviour of each available compatibility level.
 	#
-	# New EAPI note: a newer EAPI (after 8) may well adopt Bash 5.2 as its minimum version.
-	# If it does, this logic will need to be adjusted to only disable patsub_replacement
-	# and globskipdots for < ${new_api}!
-	if (( BASH_VERSINFO[0] >= 6 || ( BASH_VERSINFO[0] == 5 && BASH_VERSINFO[1] >= 2 ) )) ; then
-		shopt -u patsub_replacement globskipdots
+	# https://www.gnu.org/software/bash/manual/html_node/Shell-Compatibility-Mode.html
+	if [[ ${compat_maj} && ${compat_min} ]]; then
+		BASH_COMPAT="${compat_maj}.${compat_min}"
 	fi
 
+	# The "patsub_replacement" and "globskipdots" options were introduced
+	# by bash-5.2. Both are default-enabled and change the behaviour of
+	# bash in a manner that is backwards-incompatible. Setting BASH_COMPAT
+	# has no effect on either option. Hence, ensure that both are disabled
+	# until such time as a future EAPI not only requires >=5.2, but also
+	# mandates that the options be enabled.
+	#
+	# https://bugs.gentoo.org/881383
+	# https://bugs.gentoo.org/907061
+	# https://bugs.gentoo.org/946193
+	# https://bugs.gentoo.org/946179
+	shopt -u patsub_replacement globskipdots 2>/dev/null
+	true
 }
 __check_bash_version