power-shell-emoji-encoding

PowerShell Emoji Encoding in GitHub Actions

Problem Discovered: 2025-10-24 Status: Solved Impact: Discord webhook notifications

Problem

Emojis embedded directly in GitHub Actions YAML files get corrupted when passed to PowerShell scripts on Windows runners.

Symptom

Discord notifications show ?? instead of emojis like 📚 or ✅.

Root Cause

When GitHub Actions creates temporary PowerShell script files from YAML content, emojis get corrupted during the file encoding process:

• YAML contains: title = "📚 Documentation Deployed"
• Temp script receives: title = "ðŸ"š Documentation Deployed"
• PowerShell parser fails with: Unexpected token 'š' in expression

Solutions Attempted

❌ Attempt 1: Unicode Code Points

$bookEmoji = [char]0xD83D + [char]0xDCDA

Result: PowerShell accepted it, but Discord still displayed ?? because the encoding wasn’t proper UTF-8.

✅ Attempt 2: UTF-8 Byte Arrays (WORKING)

$utf8 = [System.Text.Encoding]::UTF8
$bookEmoji = $utf8.GetString([byte[]](0xF0, 0x9F, 0x93, 0x9A))  # 📚
$checkEmoji = $utf8.GetString([byte[]](0xE2, 0x9C, 0x85))      # ✅
$crossEmoji = $utf8.GetString([byte[]](0xE2, 0x9D, 0x8C))      # ❌

Why It Works:

• Constructs emoji from proper UTF-8 byte sequence
• Discord receives correctly encoded JSON
• No YAML-to-file corruption

Implementation

Before (Broken)

- name: Notify Discord
  shell: powershell
  run: |
    $payload = @{
      embeds = @(
        @{
          title = "📚 Documentation Deployed"  # Gets corrupted
        }
      )
    } | ConvertTo-Json -Depth 10

After (Working)

- name: Notify Discord
  shell: powershell
  run: |
    # Use UTF-8 byte arrays to properly construct emojis
    $utf8 = [System.Text.Encoding]::UTF8
    $bookEmoji = $utf8.GetString([byte[]](0xF0, 0x9F, 0x93, 0x9A))
 
    $payload = @{
      embeds = @(
        @{
          title = "$bookEmoji Documentation Deployed"
        }
      )
    } | ConvertTo-Json -Depth 10
 
    Invoke-RestMethod -Uri $env:WEBHOOK_URL `
      -Method Post `
      -Body $payload `
      -ContentType "application/json; charset=utf-8"

Common Emoji UTF-8 Encodings

Emoji	Character	UTF-8 Bytes	PowerShell Code
✅	Checkmark	E2 9C 85	$utf8.GetString([byte[]](0xE2, 0x9C, 0x85))
❌	Cross Mark	E2 9D 8C	$utf8.GetString([byte[]](0xE2, 0x9D, 0x8C))
📚	Books	F0 9F 93 9A	$utf8.GetString([byte[]](0xF0, 0x9F, 0x93, 0x9A))
📅	Calendar	F0 9F 93 85	$utf8.GetString([byte[]](0xF0, 0x9F, 0x93, 0x85))
🚀	Rocket	F0 9F 9A 80	$utf8.GetString([byte[]](0xF0, 0x9F, 0x9A, 0x80))
⚠️	Warning	E2 9A A0 EF B8 8F	$utf8.GetString([byte[]](0xE2, 0x9A, 0xA0, 0xEF, 0xB8, 0x8F))

Finding UTF-8 Bytes for Emojis

Option 1: Online Tool

• Visit: https://www.fileformat.info/info/unicode/
• Search for emoji name
• Look for “UTF-8 (hex)” section

Option 2: PowerShell

# Get UTF-8 bytes for an emoji
$emoji = "📚"
$bytes = [System.Text.Encoding]::UTF8.GetBytes($emoji)
$bytes | ForEach-Object { "0x{0:X2}" -f $_ }
# Output: 0xF0 0x9F 0x93 0x9A

References

• Issue: PR#137 self-hosted runner emoji encoding
• Fixed In: Commits 4181313, 162de59, 74a3df2, be14c95
• Affected Files:
  • .github/workflows/deploy-quartz.yml (docs repo)
  • .github/workflows/deploy-to-play-store.yml (main repo)

Best Practices

1. Always use UTF-8 byte arrays for emojis in PowerShell scripts called from GitHub Actions
2. Add comments explaining what emoji each byte array represents
3. Specify charset in Invoke-RestMethod: ContentType "application/json; charset=utf-8"
4. Test locally by creating a temp PowerShell script file and running it

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Last Updated: 2025-10-24 Pattern Status: Proven, In Production