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Lesson 7: Running a Side Effect the Tool Already Handled

File affected: scripts/actions/screenshot.sh Severity: Low — wrong clipboard content ends up in clipboard for annotate modes

What Happened

The annotate and annotate-full modes pipe the screenshot directly into satty (or swappy), which handles both saving and copying to clipboard internally:

annotate)
    grim -g "$(slurp)" - | satty - --save-file "$FILEPATH" --copy-to-clipboard
    return   # <-- returns from take_screenshot()
    ;;

But after take_screenshot returns, the script unconditionally ran:

# Copy to clipboard (if file was created)
if $CLIPBOARD && [ -f "$FILEPATH" ]; then
    wl-copy < "$FILEPATH"   # BUG: overwrites what satty already put in the clipboard
fi

satty --copy-to-clipboard copies the annotated image (with drawings, arrows, text overlays). The wl-copy block then reads the raw saved file and overwrites the clipboard with the un-annotated version. The user's annotations are lost from the clipboard even though they're saved to disk.

The Fix

Guard the clipboard block against the modes that already handle it:

# Skip clipboard copy for annotate modes — satty/swappy already handled it
if $CLIPBOARD && [ -f "$FILEPATH" ] && [[ "$MODE" != "annotate" && "$MODE" != "annotate-full" ]]; then
    if command -v wl-copy &>/dev/null; then
        wl-copy < "$FILEPATH"
    fi
    pass "Copied to clipboard"
fi

The General Pattern

This class of bug happens whenever: 1. A tool is invoked with a flag that performs side effect X. 2. The calling script also performs side effect X after the tool returns.

The result is side effect X happening twice — sometimes harmlessly (double notification), sometimes destructively (second write overwrites the first).

tool --do-the-thing       <-- does X internally
calling_script_also_does_X  <-- overwrites or duplicates

How to Catch It

Before adding a post-action step, ask: - Does any tool in the pipeline already do this? - Check man <tool> or <tool> --help for flags like --copy-to-clipboard, --notify, --save, --output.

For satty: satty --help | grep clip For swappy: swappy --help | grep output

If the tool handles it, skip the post-step, or make the post-step conditional.

When neither satty nor swappy is installed, the fallback captures to $FILEPATH and returns normally — in that case the clipboard block should run. The conditional fix above handles this correctly: the block only skips when MODE is an annotate mode, not when the fallback path is taken (the file is still created and the clipboard block fires normally).