feat(makechrootpkg): add option to interactively inspect the chroot

Implement the -x option for makechrootpkg which allows to get an
interactive shell in the chroot after building the package. Useful to
ease the debugging of a package build.

Depending on the argument, the interactive shell is either always
spawned or only when an error occurred during build.

This option is also forwarded from `pkgctl build` via the `--inspect`
flag.

Component: pkgctl build
Component: makechrootpkg
Signed-off-by: Levente Polyak <anthraxx@archlinux.org>

7 files changed, 75 insertions, 5 deletions

diff --git a/contrib/completion/bash/devtools.in b/contrib/completion/bash/devtools.in
index e0fca51..b347b31 100644
--- a/contrib/completion/bash/devtools.in
+++ b/contrib/completion/bash/devtools.in
@@ -7,6 +7,8 @@ _DEVTOOLS_LIBRARY_DIR=${_DEVTOOLS_LIBRARY_DIR:-@pkgdatadir@}
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-tags.sh
 # shellcheck source=src/lib/valid-repos.sh
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-repos.sh
+# shellcheck source=src/lib/valid-inspect.sh
+source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-inspect.sh
 
 _binary_arch=${DEVTOOLS_VALID_ARCHES[*]:0:-1}
 _colors=(never always auto)
@@ -24,6 +26,7 @@ _makechrootpkg_args=(
 	-n
 	-T
 	-U
+	-x
 )
 _makechrootpkg_args_d_opts() { _filedir -d; }
 _makechrootpkg_args_D_opts() { _filedir -d; }
@@ -31,6 +34,7 @@ _makechrootpkg_args_r_opts() { _filedir -d; }
 _makechrootpkg_args_I_opts() { _filedir '*.pkg.tar.*'; }
 _makechrootpkg_args_l_opts() { _filedir -d; }
 _makechrootpkg_args_U_opts() { :; }
+_makechrootpkg_args_x_opts() { _devtools_completions_inspect; }
 _makechrootpkg() { __devtools_complete _makechrootpkg; }
 complete -F _makechrootpkg makechrootpkg
 
@@ -169,6 +173,7 @@ _pkgctl_build_args=(
 	-o --offload
 	-c --clean
 	-w --worker
+	--inspect
 
 	--pkgver
 	--pkgrel
@@ -186,6 +191,7 @@ _pkgctl_build_args__arch_opts() { _devtools_completions_arch; }
 _pkgctl_build_args__repo_opts() { _devtools_completions_repo; }
 _pkgctl_build_args__worker_opts() { :; }
 _pkgctl_build_args_w_opts() { _pkgctl_build_args__worker_opts; }
+_pkgctl_build_args__inspect_opts() { _devtools_completions_inspect; }
 _pkgctl_build_args__pkgver_opts() { :; }
 _pkgctl_build_args__pkgrel_opts() { :; }
 _pkgctl_build_args__message_opts() { :; }
@@ -371,6 +377,9 @@ _devtools_completions_all_packages() {
 _devtools_completions_protocol() {
 	mapfile -t COMPREPLY < <(compgen -W "https" -- "$cur")
 }
+_devtools_completions_inspect() {
+	mapfile -t COMPREPLY < <(compgen -W "${DEVTOOLS_VALID_INSPECT_MODES[*]}" -- "$cur")
+}
 
 __devtools_complete() {
 	local service=$1
diff --git a/contrib/completion/zsh/_devtools.in b/contrib/completion/zsh/_devtools.in
index d3d6df0..feeb2c2 100644
--- a/contrib/completion/zsh/_devtools.in
+++ b/contrib/completion/zsh/_devtools.in
@@ -7,6 +7,8 @@ _DEVTOOLS_LIBRARY_DIR=${_DEVTOOLS_LIBRARY_DIR:-@pkgdatadir@}
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-tags.sh
 # shellcheck source=src/lib/valid-repos.sh
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-repos.sh
+# shellcheck source=src/lib/valid-inspect.sh
+source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-inspect.sh
 
 _binary_arch=${DEVTOOLS_VALID_ARCHES[*]:0:-1}
 _colors=(never always auto)
@@ -42,6 +44,7 @@ _pkgctl_build_args=(
 	'(-o --offload)'{-o,--offload}'[Build on a remote server and transfer artifacts afterwards]'
 	'(-c --clean)'{-c,--clean}'[Recreate the chroot before building]'
 	'(-I --install)'{-I,--install}'[Install a package into the working copy of the chroot]:target:_files -g "*.pkg.tar.*(.)"'
+	"--inspect[Spawn an interactive shell to inspect the chroot (never, always, failure)]:inspect:($DEVTOOLS_VALID_INSPECT_MODES[*])"
 	'(-w --worker)'{-w,--worker}'[Name of the worker slot, useful for concurrent builds (disables auto-detection)]:slot:'
 	'--nocheck[Do not run the check() function in the PKGBUILD]'
 	'--pkgver=[Set pkgver, reset pkgrel and update checksums]:pkgver:'
@@ -190,6 +193,7 @@ _makechrootpkg_args=(
 	'-n[Run namcap on the package]'
 	'-T[Build in a temporary directory]'
 	'-U[Run makepkg as a specified user]:makepkg_user'
+	"-x[Spawn an interactive shell to inspect the chroot (never, always, failure)]:inspect:($DEVTOOLS_VALID_INSPECT_MODES[*])"
 )
 
 _mkarchroot_args=(
diff --git a/doc/man/makechrootpkg.1.asciidoc b/doc/man/makechrootpkg.1.asciidoc
index 12d32f1..3aa1be5 100644
--- a/doc/man/makechrootpkg.1.asciidoc
+++ b/doc/man/makechrootpkg.1.asciidoc
@@ -73,4 +73,8 @@ Options
 *-U*::
 	Run makepkg as a specified user
 
+*-x* <when>::
+	Inspect chroot after build, possible modes are 'never' (default), 'always' or 'failure'
+
+
 include::include/footer.asciidoc[]
diff --git a/doc/man/pkgctl-build.1.asciidoc b/doc/man/pkgctl-build.1.asciidoc
index 2637ebc..3f2d44e 100644
--- a/doc/man/pkgctl-build.1.asciidoc
+++ b/doc/man/pkgctl-build.1.asciidoc
@@ -38,6 +38,10 @@ Build Options
 *-I, --install* 'FILE'::
 	Install a package into the working copy of the chroot
 
+*--inspect* 'WHEN'::
+	Spawn an interactive shell to inspect the chroot after building. Useful to ease the debugging of a package build. +
+	Possible values for 'WHEN' are `'never'`, `'always'` or `'failure'`
+
 *-w, --worker* 'SLOT'::
 	Name of the worker slot, useful for concurrent builds. By default the slot
 	is automatically assigned to the current tty pts number. In case the caller
diff --git a/src/lib/build/build.sh b/src/lib/build/build.sh
index 8d58b63..2b9d4cf 100644
--- a/src/lib/build/build.sh
+++ b/src/lib/build/build.sh
@@ -20,6 +20,8 @@ source "${_DEVTOOLS_LIBRARY_DIR}"/lib/util/pacman.sh
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-repos.sh
 # shellcheck source=src/lib/valid-tags.sh
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-tags.sh
+# shellcheck source=src/lib/valid-inspect.sh
+source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-inspect.sh
 
 source /usr/share/makepkg/util/config.sh
 source /usr/share/makepkg/util/message.sh
@@ -48,6 +50,7 @@ pkgctl_build_usage() {
 		    -o, --offload        Build on a remote server and transfer artifacts afterwards
 		    -c, --clean          Recreate the chroot before building
 		    -I, --install FILE   Install a package into the working copy of the chroot
+		    --inspect WHEN       Spawn an interactive shell to inspect the chroot (never, always, failure)
 		    -w, --worker SLOT    Name of the worker slot, useful for concurrent builds (disables automatic names)
 		    --nocheck            Do not run the check() function in the PKGBUILD
 
@@ -218,6 +221,14 @@ pkgctl_build() {
 				warning 'not running checks is disallowed for official packages, except for bootstrapping. Please rebuild after bootstrapping is completed!'
 				shift
 				;;
+			--inspect)
+				(( $# <= 1 )) && die "missing argument for %s" "$1"
+				if ! in_array "${2}" "${DEVTOOLS_VALID_INSPECT_MODES[@]}"; then
+					die "Invalid inspect mode: %s" "${2}"
+				fi
+				MAKECHROOT_OPTIONS+=("-x" "${2}")
+				shift 2
+				;;
 			-r|--release)
 				# shellcheck source=src/lib/release.sh
 				source "${_DEVTOOLS_LIBRARY_DIR}"/lib/release.sh
diff --git a/src/lib/valid-inspect.sh b/src/lib/valid-inspect.sh
new file mode 100644
index 0000000..3b5dcad
--- /dev/null
+++ b/src/lib/valid-inspect.sh
@@ -0,0 +1,10 @@
+#!/hint/bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# shellcheck disable=2034
+DEVTOOLS_VALID_INSPECT_MODES=(
+	never
+	always
+	failure
+)
diff --git a/src/makechrootpkg.in b/src/makechrootpkg.in
index 2cfd849..14b8f11 100644
--- a/src/makechrootpkg.in
+++ b/src/makechrootpkg.in
@@ -8,9 +8,12 @@ _DEVTOOLS_LIBRARY_DIR=${_DEVTOOLS_LIBRARY_DIR:-@pkgdatadir@}
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/common.sh
 # shellcheck source=src/lib/archroot.sh
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/archroot.sh
+# shellcheck source=src/lib/valid-inspect.sh
+source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-inspect.sh
 
 
 source /usr/share/makepkg/util/config.sh
+source /usr/share/makepkg/util/util.sh
 
 shopt -s nullglob
 
@@ -31,6 +34,8 @@ run_checkpkg=0
 temp_chroot=0
 tmp_opts="nosuid,nodev,size=50%,nr_inodes=2m"
 
+inspect=never
+
 bindmounts_ro=()
 bindmounts_rw=()
 
@@ -76,6 +81,7 @@ usage() {
 	echo '-C         Run checkpkg on the package'
 	echo '-T         Build in a temporary directory'
 	echo '-U         Run makepkg as a specified user'
+	echo '-x <when>  Inspect chroot after build (never, always, failure)'
 	exit 1
 }
 
@@ -280,7 +286,7 @@ move_products() {
 }
 # }}}
 
-while getopts 'hcur:I:l:nCTD:d:U:' arg; do
+while getopts 'hcur:I:l:nCTD:d:U:x:' arg; do
 	case "$arg" in
 		c) clean_first=1 ;;
 		D) bindmounts_ro+=("--bind-ro=$OPTARG") ;;
@@ -293,6 +299,7 @@ while getopts 'hcur:I:l:nCTD:d:U:' arg; do
 		C) run_checkpkg=1 ;;
 		T) temp_chroot=1; copy+="-$$" ;;
 		U) makepkg_user="$OPTARG" ;;
+		x) inspect="$OPTARG" ;;
 		h|*) usage ;;
 	esac
 done
@@ -314,6 +321,10 @@ else
 	copydir="$chrootdir/$copy"
 fi
 
+if ! in_array "${inspect}" "${DEVTOOLS_VALID_INSPECT_MODES[@]}"; then
+	die "Invalid inspect mode: %s" "${inspect}"
+fi
+
 # Pass all arguments after -- right to makepkg
 makepkg_args+=("${@:$OPTIND}")
 
@@ -368,11 +379,16 @@ download_sources
 
 prepare_chroot
 
+nspawn_build_args=(
+	--bind="${PWD//:/\\:}:/startdir"
+	--bind="${SRCDEST//:/\\:}:/srcdest"
+	--tmpfs="/tmp:${tmp_opts}"
+	"${bindmounts_ro[@]}"
+	"${bindmounts_rw[@]}"
+)
+
 if arch-nspawn "$copydir" \
-	--bind="${PWD//:/\\:}:/startdir" \
-	--bind="${SRCDEST//:/\\:}:/srcdest" \
-	--tmpfs="/tmp:${tmp_opts}" \
-	"${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
+	"${nspawn_build_args[@]}" \
 	/chrootbuild "${makepkg_args[@]}"
 then
 	mapfile -t pkgnames < <(sudo -u "$makepkg_user" bash -c 'source PKGBUILD; printf "%s\n" "${pkgname[@]}"')
@@ -382,6 +398,18 @@ else
 	move_logfiles
 fi
 
+if [[ $inspect == always ]] || ( [[ $inspect == failure ]] && (( ret != 0 )) ); then
+	if (( ret == 0 )); then
+		msg "Build succeeded, inspecting %s" "$copydir"
+	else
+		error "Build failed, inspecting %s" "$copydir"
+	fi
+	arch-nspawn "$copydir" \
+		"${nspawn_build_args[@]}" \
+		--user=builduser \
+		--chdir=/build
+fi
+
 (( temp_chroot )) && delete_chroot "$copydir" "$copy"
 
 if (( ret != 0 )); then