fix(installer): skip node/npm/npx symlinks for user installs

[Lee-Si-Yoon]

What

install_node_line() symlinks node/npm/npx into ~/.local/bin for user installs. rc files prepend that dir for uv, pipx, etc., so the links override the user's own Node in every interactive shell. which node resolves to Hermes' bundled Node, not nvm/Homebrew/volta.

Fixes #45279.

Fix

Gate the symlinks on install layout:

• root FHS (/usr/local/bin): keep. Stock root shell has no other PATH entry for node.
• Termux ($PREFIX/bin): keep. Same reason.
• user (~/.local/bin): skip. Hermes finds its own Node by absolute path through find_hermes_node_executable(), not via PATH, so skipping is safe.

Why prior PRs stalled

• fix(install): skip node/npm/npx symlinks when system versions exist #45282 (open) used command -v as the gate. Maintainer pointed out this also suppresses the link for root FHS when the PATH Node is too old, leaving the root recovery path without node.
• fix(install): keep managed node private #49426 dropped the links entirely and regressed root FHS.
• fix(installer): skip node/npm/npx symlinks for user installs (#45279) #45384 went stale.

This PR keys the decision on $ROOT_FHS_LAYOUT, the same variable get_command_link_dir() uses, so root FHS keeps its links and only the user case changes.

check_node() only reaches install_node_line() when the system Node was too old or had a bad npm band. The managed Node is what the install needs internally; this PR just stops dropping it into the user's interactive PATH.

Repro

Before (user install with nvm v24.21.0):

$ which node
/home/siyoon/.local/bin/node  ->  ~/.hermes/node/bin/node (Hermes v26.8.1)
$ node -v
v26.8.1

After:

$ which node
/home/siyoon/.nvm/versions/node/v24.21.0/bin/node
$ node -v
v24.21.0

Hermes still resolves its own Node: ~/.hermes/node/bin/node --version reports v26.8.1.

[alt-glitch]

This was generated by AI during triage.

Related: #45282 (open) fixes the same #45279 shadowing with a different gate (skip symlinks only when system node/npm already exist) and #45384 was an earlier closed-stale attempt with the layout gate used here. Two open approaches for a maintainer to pick between.

[kyssta-exe]

Review: fix(installer): skip node/npm/npx symlinks for user installs

Summary
Stops user-layout installs from symlinking the managed Node into ~/.local/bin, where rc-file PATH prepending let it shadow the user's own toolchain (nvm/Homebrew/volta) in every interactive shell. Root FHS and Termux layouts keep the links. Fixes #45279.

What changed

• scripts/install.sh (install_node_line) — symlink block gated on [ "$ROOT_FHS_LAYOUT" = true ] || is_termux, with a thorough comment explaining the gate and why skipping is safe (find_hermes_node_executable resolves by absolute path; with_hermes_node_path scopes PATH to Hermes-owned subprocesses).

Strengths

• Keys the decision on $ROOT_FHS_LAYOUT (the same variable get_command_link_dir() uses) rather than command -v, directly addressing why fix(install): skip node/npm/npx symlinks when system versions exist #45282 stalled and avoiding fix(install): keep managed node private #49426's root-FHS regression. Shows real familiarity with the prior-art failure modes.
• Before/after which node repro included.

Findings

• Edge: if is_termux is a function, || is_termux as a bare command in the [ ... ] || chain is correct; just confirming it's a predicate function and not a variable (unquoted $is_termux would behave differently) — the surrounding style suggests function, fine.
• Non-blocking: the else branch log_info fires on every user install that reaches this path. Appropriate visibility, no change needed.

Verdict
Looks good to merge.

Reviewed using Hermes-Agent