Bug: Bash/PowerShell completions don't show parent flags for commands with subcommands

[TabishB]

Summary

When a command has both flags AND subcommands, Bash and PowerShell generators only offer subcommands at the parent level, never the parent flags. Fish handles this correctly.

Example

For a command structure like:

openspec config
    ├── FLAGS: --scope, --json
    └── SUBCOMMANDS: set, get, list

Expected behavior

$ openspec config --<TAB>
--scope    --json    set    get    list

Actual behavior

$ openspec config --<TAB>
set    get    list          # Parent flags missing!

Affected Shells

Shell	Works?
Fish	✅ Yes
Bash	❌ No
PowerShell	❌ No

Root Cause

In bash-generator.ts (generateCommandCase method), when subcommands exist:

if (cmd.subcommands && cmd.subcommands.length > 0) {
  lines.push(`${indent}if [[ $cword -eq 2 ]]; then`);
  lines.push(`${indent}  local subcommands="..."`);
  lines.push(`${indent}  COMPREPLY=(...)`);
  lines.push(`${indent}  return 0`);  // ← Exits immediately, never offers parent flags
  lines.push(`${indent}fi`);

PowerShell has the same pattern.

Fish correctly handles this at line 1216-1219:

// Add flags for parent command
for (const flag of cmd.flags) {
  lines.push(...this.generateFlagCompletion(flag, `__fish_openspec_using_subcommand ${cmd.name}`));
}

Suggested Fix

Check if user is typing a flag ($cur starts with -) and offer parent flags in that case:

if [[ $cword -eq 2 ]]; then
  if [[ "$cur" == -* ]]; then
    # Offer parent command flags
    local flags="--scope --json"
    COMPREPLY=($(compgen -W "$flags" -- "$cur"))
  else
    # Offer subcommands
    local subcommands="set get list"
    COMPREPLY=($(compgen -W "$subcommands" -- "$cur"))
  fi
  return 0
fi

Files to Modify

• src/core/completions/generators/bash-generator.ts
• src/core/completions/generators/powershell-generator.ts

Related

Discovered during review of PR #401 (multi-shell completion support).