Diagnose the retry that follows a deleted package

configs/airootfs/usr/local/bin/omarchy-install-diagnose-media

@@ -47,6 +47,21 @@ corrupt_package() {
   printf '%s' "$package"
 }
 
+# A retry in the same boot never gets as far as a checksum. The first failure
+# unlinked the package through the bind mount, so pacman now fails opening it,
+# and it names the mirror it read from rather than the cache it writes to.
+deleted_package() {
+  local log match package=""
+
+  for log in "$@"; do
+    [[ -f $log ]] || continue
+    match=$(sed -n "s|.*Could not open file ${OFFLINE_MIRROR}/\([^ ]*\).*|\1|p" "$log" | tail -n 1)
+    [[ -n $match ]] && package="$match"
+  done
+
+  printf '%s' "$package"
+}
+
 expected_checksum() {
   local package="$1" reader
 
@@ -77,7 +92,14 @@ actual_checksum() {
   printf '%s' "${sum%% *}"
 }
 
+# The checksum failure is read first wherever both are in the log: it is the
+# attempt that names the cause, and the open failures after it are its wake.
 package=$(corrupt_package "$@")
+deleted=""
+if [[ -z $package ]]; then
+  package=$(deleted_package "$@")
+  deleted=1
+fi
 if [[ -z $package ]]; then
   exit 1
 fi
@@ -87,6 +109,20 @@ fi
 # filename has no business containing before printing it.
 display_package="${package//[^A-Za-z0-9._+:@%-]/}"
 
+# Nothing can be weighed here: the bytes that failed are gone, and the copy in
+# the mirror went with them. Say which attempt this is, because the screen
+# otherwise repeats the same unreadable error for every retry and the one that
+# explains it scrolled away with the first.
+if [[ -n $deleted ]]; then
+  echo "An earlier attempt deleted this package"
+  echo "pacman rejected it off this ISO and unlinked it from the mirror:"
+  echo "$display_package"
+  echo
+  echo "Reboot before retrying: the deletion is in RAM, so the ISO's copy returns"
+  echo "The first error after that reboot is the one that names the fault"
+  exit 0
+fi
+
 expected=$(expected_checksum "$package")
 actual=$(actual_checksum "$package")
 

test/unit/install-media-diagnosis-test.sh

@@ -142,6 +142,65 @@ if grep -qF "no longer matches the checksum" <<<"$output"; then
 fi
 pass "a deleted package names the medium without claiming which way it failed"
 
+# Every retry in the same boot fails on the open rather than the checksum, and
+# pacman names the mirror it read from, not the cache it writes to.
+write_retry_log() {
+  local log="$1" path="${2:-$mirror/$PACKAGE}"
+
+  {
+    echo "[dashboard] :: Retrieving packages..."
+    echo "[dashboard] error: failed retrieving file '${path##*/}' from disk : Could not open file $path"
+    echo "[dashboard] error: failed to commit transaction (download library error)"
+    echo "[dashboard] ==> ERROR: Failed to install packages to new root"
+  } >"$log"
+}
+
+write_retry_log "$work/retry.log"
+
+set +e
+output=$(diagnose "$work/retry.log")
+status=$?
+set -e
+
+(( status == 0 )) || fail "a retry after the deletion is diagnosed" "exit status $status"
+[[ $(head -n 1 <<<"$output") == "An earlier attempt deleted this package" ]] ||
+  fail "a retry is diagnosed as a retry" "$output"
+grep -qF "$PACKAGE" <<<"$output" || fail "a retry names the package" "$output"
+grep -qF "Reboot before retrying" <<<"$output" ||
+  fail "a retry says how to get the package back" "$output"
+pass "a retry after the deletion says so instead of going undiagnosed"
+
+# A log holding both attempts must answer with the one that names the cause.
+# The retries come after it and would otherwise win on recency.
+printf 'a package, but damaged\n' >"$mirror/$PACKAGE"
+write_mirror_db "$(printf '0%.0s' {1..64})"
+{
+  cat "$log"
+  cat "$work/retry.log"
+} >"$work/both.log"
+
+set +e
+output=$(diagnose "$work/both.log")
+set -e
+
+[[ $(head -n 1 <<<"$output") == "The install medium is damaged" ]] ||
+  fail "the checksum failure outranks the retries that followed it" "$output"
+pass "the checksum failure outranks the retries that followed it"
+
+# An open failure somewhere other than the mirror was not read off this ISO.
+write_retry_log "$work/retry-elsewhere.log" "/var/tmp/build/$PACKAGE"
+
+set +e
+output=$(diagnose "$work/retry-elsewhere.log")
+status=$?
+set -e
+
+(( status == 1 )) || fail "an open failure outside the mirror is not diagnosed" "exit $status: $output"
+[[ -z $output ]] || fail "an open failure outside the mirror prints nothing" "$output"
+pass "an open failure outside the mirror is not blamed on the medium"
+
+rm "$mirror/$PACKAGE"
+
 # A record with no %SHA256SUM% must not borrow the next record's, which would
 # compare a real file against another package's checksum.
 printf 'a package, but damaged\n' >"$mirror/$PACKAGE"