Expand Ecosystem Context with nvm/rustup deep dives and command comparisons

[Copilot]

Adds detailed ecosystem analysis to the CLI acquisition tool design document, providing historical context and command references for nvm and rustup to inform dotnetup's design.

Changes

Deep Dive Sections

• nvm (Node.js): Historical evolution from system-wide installs causing EACCES permission errors to user-local installations in ~/.nvm. Includes 8-command reference table covering LTS installation, version switching, and package migration.

• rustup (Rust): Evolution from multirust shell script to official Rust toolchain manager. Highlights auto-install killer feature where cargo build automatically installs missing toolchains specified in rust-toolchain.toml. Includes 11-command reference table.

Ecosystem Command Comparison

12-row comparison table mapping common version management tasks across nvm, rustup, and proposed dotnetup commands:

Task	nvm (Node)	rustup (Rust)	dotnetup (Proposed)
Install latest stable/LTS	nvm install --lts	rustup install stable	dnup install --lts
Auto-install on project entry	Manual (shell hook)	Automatic	Should be automatic
Self-update	N/A (git pull)	rustup self update	dnup update --self

UX Lessons

Synthesizes key takeaways for dotnetup design:

• Permission problems drove nvm adoption—solving real pain is critical
• Rustup's auto-install on project entry (via rust-toolchain.toml) is a killer feature that .NET's global.json currently lacks
• Identifies gap: dotnetup should detect global.json and auto-install missing SDKs, matching rustup's workflow

Original prompt

Summary

Expand the "Ecosystem Context" section in the accepted/2025/cli-acquisition-tool.md design document to include detailed background on how nvm (Node.js) and rustup (Rust) handle version management, including:

1. Historical context for why each ecosystem moved toward user-local installations
2. Detailed command reference showing how developers accomplish common tasks
3. Command comparison table mapping nvm/rustup commands to proposed dotnetup equivalents

Detailed Requirements

1. Add "Deep Dive: nvm (Node.js)" Section

After the existing "Key Observations from Other Ecosystems" section, add a new subsection that covers:

Historical Context:

• Early Node.js was installed system-wide via OS package managers
• npm install -g to system directories caused EACCES permission errors on Unix
• Using sudo created ownership conflicts and security concerns
• Tim Caswell created nvm (2011) to solve these problems by installing Node.js per-user in ~/.nvm
• The official npm documentation now recommends nvm as the primary solution for permission issues

Key Design Principles:

• All Node versions install to ~/.nvm/versions/node/
• Global npm packages are scoped per-Node-version
• No admin rights required
• Per-project version pinning via .nvmrc file

Command Reference Table showing:

Task	Command
Install latest LTS	nvm install --lts
Install specific version	nvm install 20.10.0
Install named LTS	nvm install lts/iron
List available versions	nvm ls-remote
Use version in current shell	nvm use 20.10.0
Set permanent default	nvm alias default 20.10.0
Upgrade + migrate packages	nvm install --lts --reinstall-packages-from=$(nvm current)
Per-project pinning	.nvmrc file with version, then nvm use

2. Add "Deep Dive: rustup (Rust)" Section

Add a similar subsection for Rust covering:

Historical Context:

• Brian Anderson created multirust (2014) as a shell script for managing Rust toolchains
• Rewritten in Rust as rustup (2016) and moved under official Rust governance
• User-local installation (~/.rustup, ~/.cargo) was a core design principle from day one
• Designed for frequent switching between stable/beta/nightly channels

Key Design Principles:

• Toolchains install to ~/.rustup/toolchains/
• No root/admin needed for any operation
• Per-directory overrides and rust-toolchain.toml for project pinning
• Killer feature: Running cargo build with a rust-toolchain.toml auto-installs the required toolchain

Command Reference Table showing:

Task	Command
Install stable	rustup install stable
Install nightly	rustup install nightly
Install specific version	rustup install 1.75.0
Install specific nightly	rustup install nightly-2024-01-15
Update all toolchains	rustup update
Update specific channel	rustup update stable
Self-update	rustup self update
Set default toolchain	rustup default stable
Override for directory	rustup override set nightly
One-off command	cargo +nightly build
Per-project pinning	rust-toolchain.toml file (auto-installs on first use)

3. Add "Command Comparison: Ecosystem Tools" Section

Add a comprehensive comparison table mapping commands across ecosystems:

Task	nvm (Node)	rustup (Rust)	dotnetup (Proposed)
Install latest stable/LTS	nvm install --lts	rustup install stable	dnup install --lts
Install specific version	nvm install 20.10.0	rustup install 1.75.0	dnup install 8.0.100
Install preview/nightly	nvm install node	rustup install nightly	dnup install preview
Update all	N/A (install new)	rustup update	dnup update
Check for updates	nvm ls-remote	rustup update (reports)	dnup update --check
List installed	nvm ls	rustup toolchain list	dnup list
Use in current shell	nvm use 20.10.0	N/A	dnup use 8.0
Set permanent default	nvm alias default 20	rustup default stable	dnup default 8.0
Per-project pin file	.nvmrc	rust-toolchain.toml	global.json
Auto-install on project entry	Manual (shell hook)	Automatic	Should be automatic
One-off command	nvm exec 18 node app.js	cargo +1.75 build	TBD
Self-update	N/A (git pull)	rustup self update	dnup update --self

4. Add "UX Lessons for dotnetup" Section

Add a brief section summarizing key takeaways:

From nvm:

• Permission problems drove tool adoption - solving real daily pain
• Per-version isolation of global packages prevents subtle breakage
• Community tools can become official recommendations

From rustup:

• Design for multi-toolchain from the start
• Auto-install on project entry (via rust-toolchain.toml) is a killer feature that .NET's global.jso...

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