Preserve empty adapter metadata fields

scripts/helpers.sh

@@ -96,22 +96,46 @@ get_nowplaying_status_icon() {
 }
 
 # Parse adapter output.
-# Preferred adapter format: status<TAB>artist<TAB>title.
-# Plain text remains supported as playing metadata for compatibility.
+# Adapter format: status<TAB>artist<TAB>title.
 parse_nowplaying_adapter_output() {
-    local adapter_output="$1"
-    local status
-    local artist
-    local title
-    local text
-
-    if [[ "$adapter_output" == *$'\t'* ]]; then
-        IFS=$'\t' read -r status artist title <<< "$adapter_output"
-        text="$(format_nowplaying_metadata "$artist" "$title")"
-        printf '%s\t%s\n' "${status:-Playing}" "$text"
-    else
-        printf 'Playing\t%s\n' "$adapter_output"
+    local adapter_output_value="$1"
+    local status_output_name="$2"
+    local artist_output_name="$3"
+    local title_output_name="$4"
+    local parsed_status
+    local adapter_remainder
+    local parsed_artist
+    local parsed_title
+
+    printf -v "$status_output_name" '%s' ''
+    printf -v "$artist_output_name" '%s' ''
+    printf -v "$title_output_name" '%s' ''
+
+    case "$adapter_output_value" in
+        *$'\n'*|*$'\r'*) return 1 ;;
+    esac
+
+    if [[ "$adapter_output_value" != *$'\t'* ]]; then
+        return 1
+    fi
+
+    parsed_status="${adapter_output_value%%$'\t'*}"
+    adapter_remainder="${adapter_output_value#*$'\t'}"
+
+    if [[ -z "$parsed_status" || "$adapter_remainder" != *$'\t'* ]]; then
+        return 1
     fi
+
+    parsed_artist="${adapter_remainder%%$'\t'*}"
+    parsed_title="${adapter_remainder#*$'\t'}"
+
+    if [[ "$parsed_title" == *$'\t'* ]]; then
+        return 1
+    fi
+
+    printf -v "$status_output_name" '%s' "$parsed_status"
+    printf -v "$artist_output_name" '%s' "$parsed_artist"
+    printf -v "$title_output_name" '%s' "$parsed_title"
 }
 
 # Get the tmux status interval to restore after temporary scrolling changes.

scripts/nowplaying.sh

@@ -32,13 +32,17 @@ case "$(uname -s)" in
         ;;
 esac
 
+playback_status=""
+track_artist=""
+track_title=""
+track_text=""
+
 # If we got output, process and display it
-if [ -n "$output" ]; then
-    parsed_output="$(parse_nowplaying_adapter_output "$output")"
-    IFS=$'\t' read -r playback_status track_text <<< "$parsed_output"
+if [ -n "$output" ] && parse_nowplaying_adapter_output "$output" playback_status track_artist track_title; then
+    track_text="$(format_nowplaying_metadata "$track_artist" "$track_title")"
 fi
 
-if [ -n "${track_text:-}" ]; then
+if [ -n "$track_text" ]; then
     status_icon="$(get_nowplaying_status_icon "$playback_status")"
 
     # Check if scrolling is needed

scripts/test.sh

@@ -32,6 +32,41 @@ assert_eq() {
     printf 'ok - %s\n' "$message"
 }
 
+assert_adapter_record() {
+    local adapter_output="$1"
+    local expected_status="$2"
+    local expected_artist="$3"
+    local expected_title="$4"
+    local message="$5"
+    local playback_status="stale"
+    local track_artist="stale"
+    local track_title="stale"
+
+    if ! parse_nowplaying_adapter_output "$adapter_output" playback_status track_artist track_title; then
+        fail "${message} was rejected"
+    fi
+
+    assert_eq "$expected_status" "$playback_status" "${message} status"
+    assert_eq "$expected_artist" "$track_artist" "${message} artist"
+    assert_eq "$expected_title" "$track_title" "${message} title"
+}
+
+assert_adapter_rejected() {
+    local adapter_output="$1"
+    local message="$2"
+    local playback_status="stale"
+    local track_artist="stale"
+    local track_title="stale"
+
+    if parse_nowplaying_adapter_output "$adapter_output" playback_status track_artist track_title; then
+        fail "${message} was accepted"
+    fi
+
+    assert_eq "" "$playback_status" "${message} clears status"
+    assert_eq "" "$track_artist" "${message} clears artist"
+    assert_eq "" "$track_title" "${message} clears title"
+}
+
 write_tmux_mock() {
     cat > "${TMP_DIR}/tmux" <<'MOCK'
 #!/usr/bin/env bash
@@ -117,6 +152,17 @@ MOCK
 ' ;;
     '-p paused metadata title') printf 'Track
 ' ;;
+MOCK
+            ;;
+        title_only)
+            cat >> "${TMP_DIR}/playerctl" <<'MOCK'
+    '-l') printf 'title-only
+' ;;
+    '-p title-only status') printf 'Playing
+' ;;
+    '-p title-only metadata artist') printf '' ;;
+    '-p title-only metadata title') printf 'Title
+' ;;
 MOCK
             ;;
         stopped)
@@ -259,8 +305,18 @@ assert_eq "value  " "$(resolve_with_mock @test_trailing_spaces fallback)" "mock
 helper_output="$(PATH="${TMP_DIR}:${PATH}" bash -c 'source "$1"; printf "%s %s %s %s\n" "$(get_tmux_integer_option @bad_integer 50 4)" "$(get_tmux_integer_option @empty_integer 50 4)" "$(get_tmux_integer_option @low_integer 50 4)" "$(get_tmux_integer_option @high_integer 1 1 10)"' _ "${ROOT_DIR}/scripts/helpers.sh")"
 assert_eq "50 50 4 10" "$helper_output" "integer option validation"
 
-parse_output="$(PATH="${TMP_DIR}:${PATH}" bash -c 'source "$1"; parse_nowplaying_adapter_output $'"'"'Paused\tArtist\tTitle'"'"'' _ "${ROOT_DIR}/scripts/helpers.sh")"
-assert_eq $'Paused\tArtist - Title' "$parse_output" "adapter output parsing"
+# shellcheck source=scripts/helpers.sh
+source "${ROOT_DIR}/scripts/helpers.sh"
+assert_adapter_record $'Paused\tArtist\tTitle' "Paused" "Artist" "Title" "complete adapter record"
+assert_adapter_record $'Playing\t\tTitle' "Playing" "" "Title" "title-only adapter record"
+assert_adapter_record $'Paused\tArtist\t' "Paused" "Artist" "" "artist-only adapter record"
+assert_adapter_record $'Stopped\t\t' "Stopped" "" "" "empty metadata adapter record"
+assert_adapter_rejected "plain text" "plain-text adapter output"
+assert_adapter_rejected $'Playing\tTitle' "one-tab adapter output"
+assert_adapter_rejected $'Playing\tArtist\tTitle\tExtra' "extra-tab adapter output"
+assert_adapter_rejected $'\tArtist\tTitle' "empty-status adapter output"
+assert_adapter_rejected $'Playing\tArtist\tTitle\nSecond' "multiline adapter output"
+assert_adapter_rejected $'Playing\tArtist\tTitle\r' "carriage-return adapter output"
 
 write_uname_mock
 
@@ -271,6 +327,10 @@ assert_eq "♪ Artist - Title" "$(run_with_mocks "${ROOT_DIR}/scripts/nowplaying
 write_playerctl_mock paused
 assert_eq "⏸ Old - Track" "$(run_with_mocks "${ROOT_DIR}/scripts/nowplaying.sh")" "main renders paused metadata"
 
+write_playerctl_mock title_only
+assert_eq $'Playing\t\tTitle' "$(run_with_mocks "${ROOT_DIR}/scripts/nowplaying_linux.sh")" "linux adapter preserves empty artist"
+assert_eq "♪ Title" "$(run_with_mocks "${ROOT_DIR}/scripts/nowplaying.sh")" "main renders title-only metadata"
+
 write_playerctl_mock stopped
 assert_eq "⏹ Done - Song" "$(run_with_mocks "${ROOT_DIR}/scripts/nowplaying.sh")" "main renders stopped metadata"