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>

3 files changed, 54 insertions, 5 deletions

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