nushell-plugins/updates/108/NUSHELL_0.108.0_QUICK_REF.md

Nushell 0.108.0 Quick Reference Card

Release: 2025-10-15 | Version: 0.108.0

🔴 Critical Breaking Changes (Action Required)

1. into value → detect type

# ❌ OLD (0.107)
$data | into value

# ✅ NEW (0.108.0)
$data | update cells {detect type}  # For table cells
$value | detect type                 # For non-tables
$custom_value | into value           # For plugin values (NEW)

2. Stream Error Collection

# ❌ OLD (0.107)
let results = $stream | collect

# ✅ NEW (0.108.0)
let results = try {
    $stream | collect
} catch { |err|
    []  # or handle error
}

3. format bits Endian

# ✅ NEW (0.108.0) - Be explicit
format bits --endian native  # Pre-0.107 behavior
format bits --endian big     # 0.107 default
format bits --endian little  # Little endian

🟡 Polars Plugin Changes

# ❌ REMOVED
polars fetch  # No replacement

# ⚠️ REQUIRES FLAG
polars pivot --stable  # Must be explicit

🟢 New Features

MCP Server (AI Agents)

# Compile with MCP support
cargo build --features mcp

# Start as MCP server
nu --mcp

Inline Completions

# Simple inline completions
def deploy [env: string@[dev staging prod]] {
    print $"Deploying to ($env)"
}

# With const variable
const environments = [dev staging prod]
def deploy [env: string@$environments] {
    print $"Deploying to ($env)"
}

New Date/Time Specifiers

date now | format date "%J"      # 20251015 (compact date)
date now | format date "%Q"      # 143022 (compact time)
date now | format date "%J%Q"    # 20251015143022 (sortable)

Enhanced Commands

# which - list all commands
which  # No args = list all

# HTTP metadata (no --full needed)
let response = http get $url
$response | metadata  # Headers now included

# metadata merge
$value | metadata set --merge {priority: 1, tag: "important"}

# each flatten
$data | each --flatten { |item| process $item }

# compact empty improvements
$data | compact --empty  # Now recognizes 0-byte binary as empty

🧪 Experimental Features

Pipefail (Opt-in)

# Enable
$env.config.experimental = { pipefail: true }

# Or command line
nu --experimental-options='pipefail'

# Effect
^false | echo ''
$env.LAST_EXIT_CODE  # Now returns 1 (was 0)

Runtime Type Checking (Opt-in)

# Enable
$env.config.experimental = { enforce-runtime-annotations: true }

# Effect
let x: int = "not a number"  # Now throws runtime error

Reorder Cell Paths (Now Default/Opt-out)

# Disable if needed
$env.config.experimental = { reorder-cell-paths: false }

# Default = enabled (performance optimization)

🪟 Windows Improvements

# Device paths now work
open \\.\NUL
save \\.\CON
source NUL

# UNC paths no longer get trailing \
\\server\share  # Not \\server\share\

🛠️ Build Changes

# Network commands now optional
cargo build --no-default-features --features network

# MCP server support
cargo build --features mcp

📋 Migration Checklist

• Find all into value usage → Replace with detect type or keep for plugin values
• Add try-catch around stream collections
• Update polars fetch calls → Remove (no replacement)
• Add --stable to polars pivot calls
• Add --endian flag to format bits calls
• Test chained power operations (2 ** 3 ** 4 now right-associative)
• Update custom builds to add --features network
• Test on Windows if applicable (UNC/device paths)
• Consider enabling experimental features for testing
• Update plugin implementations for CustomValue enhancements

🔍 Find Breaking Changes in Your Code

# Search for problematic patterns
rg "into value" . --type nu
rg "polars fetch" . --type nu
rg "format bits" . --type nu | grep -v "endian"

# Test with experimental features
nu --experimental-options='pipefail,enforce-runtime-annotations' script.nu

📊 Using the Data File

# Load module
use nushell_0.108.0_changes.nu *

# Get all changes
get-changes

# Get high impact changes only
get-high-impact-changes

# Get experimental features
get-experimental-features

# Search for specific changes
search-changes "into value"

# Generate migration report
generate-migration-report

🎯 Priority Levels

Priority	Changes	Action
HIGH	into value rename, Stream errors, Polars fetch	Must fix immediately
MEDIUM	format bits endian, Network builds, Power operator	Should address
LOW	Windows paths, Completions, HTTP metadata, Date formats	Nice to have

📚 Resources

• Full Docs: NUSHELL_0.108.0_CHANGES.md
• Data File: nushell_0.108.0_changes.nu
• Summary: NUSHELL_0.108.0_SUMMARY.md
• Release: https://www.nushell.sh/blog/2025-10-15-nushell_v0_108_0.html
• GitHub: https://github.com/nushell/nushell/releases/tag/0.108.0

🚀 Quick Migration (Most Users)

# 1. Update into value
rg "into value" . --type nu
# Replace: | update cells {detect type}

# 2. Add error handling
# Before: let x = $stream | collect
# After:  let x = try { $stream | collect } catch { [] }

# 3. Fix polars (if using)
# Remove: polars fetch
# Update: polars pivot → polars pivot --stable

# 4. Test
nu your_script.nu

Most migrations complete in < 30 minutes!

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Created: 2025-10-18 | Document Version: 1.0