feat(lockfile): add URL support for vfox backend

[jdx]

Summary

• Add get_tarball_url() implementation for vfox plugins to enable lockfile URL generation for all platforms
• Add pre_install_for_platform() method that temporarily overrides OS_TYPE/ARCH_TYPE Lua globals to query URLs for different platforms
• Map mise platform names to vfox conventions (macos→darwin, x64→amd64)
• Ensure plugin is installed before querying tarball URL (consistent with other vfox methods)

Refactoring

• Extract is_backend_plugin() and get_tool_name() helpers to reduce duplication
• Simplify error handling with ? and .wrap_err() instead of verbose match blocks
• Unify env_keys folding logic (was duplicated for backend vs traditional plugins)

Test plan

• Verified vfox crate tests pass
• Verified project builds successfully
• Test with a real vfox plugin to confirm URL generation works

🤖 Generated with Claude Code

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Note

Implements cross-platform URL generation via pre_install_for_platform (with platform name mapping) and refactors vfox backend helpers and env handling.

• Backend (mise):
  • Tarball URL resolution: Implement get_tarball_url using vfox.pre_install_for_platform(...), mapping platforms (macos→darwin, x64→amd64).
  • Refactors: Extract is_backend_plugin() and get_tool_name(); simplify backend calls with ?/wrap_err; unify env var folding for PATH and others; minor cloning/path handling fixes.
• vfox crate:
  • Plugin: Add Plugin::pre_install_for_platform(version, os, arch) that temporarily overrides Lua OS_TYPE/ARCH_TYPE and restores them.
  • API: Add Vfox::pre_install_for_platform(...) proxy to plugin method.

^{Written by Cursor Bugbot for commit ef54195. This will update automatically on new commits. Configure here.}

[Copilot]

Pull request overview

This PR adds lockfile URL support for vfox backend plugins by implementing cross-platform URL generation capabilities. The implementation enables mise to query download URLs for tools across different platforms (OS/architecture combinations) by temporarily overriding vfox's platform globals during plugin execution.

Key Changes:

• Implements get_tarball_url() in VfoxBackend to generate lockfile URLs with platform name mapping (macos→darwin, x64→amd64)
• Adds pre_install_for_platform() method that temporarily overrides OS_TYPE/ARCH_TYPE Lua globals to query URLs for specific platforms
• Introduces new async method in vfox crate to support cross-platform pre-install queries

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/backend/vfox.rs	Implements get_tarball_url() with platform name mapping and calls new pre_install_for_platform() method
crates/vfox/src/vfox.rs	Adds public async wrapper pre_install_for_platform() to invoke plugin-specific platform queries
crates/vfox/src/hooks/pre_install.rs	Implements core logic to temporarily override Lua globals (OS_TYPE/ARCH_TYPE) for cross-platform URL generation

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[Copilot]

The global variable override pattern may cause issues in concurrent scenarios. If multiple calls to pre_install_for_platform() execute simultaneously, they could interfere with each other's OS_TYPE/ARCH_TYPE values. Consider using a more isolated approach, such as passing platform parameters directly to the plugin function if the vfox plugin API supports it, or ensuring this method is called under a lock.

Suggested change

	-- Override globals with target platform for cross-platform URL generation
	local saved_os = OS_TYPE
	local saved_arch = ARCH_TYPE
	OS_TYPE = $target_os
	ARCH_TYPE = $target_arch
	local result = PLUGIN:PreInstall($ctx)
	-- Restore original values
	OS_TYPE = saved_os
	ARCH_TYPE = saved_arch
	return result
	-- Pass target_os and target_arch as arguments to PreInstall
	return PLUGIN:PreInstall($ctx, $target_os, $target_arch)

[Copilot]

[nitpick] The variable _log_rx is prefixed with underscore indicating it's intentionally unused, but this pattern suggests the log receiver is being ignored. Consider either removing the underscore if logs should be handled, or add a comment explaining why logs are intentionally discarded in this context.

[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.11.10 x -- echo	20.1 ± 0.7	18.7	23.0	1.00
mise x -- echo	20.8 ± 0.8	18.9	23.2	1.03 ± 0.05

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.11.10 env	19.6 ± 0.6	18.5	22.5	1.00
mise env	20.2 ± 1.0	18.2	27.3	1.03 ± 0.06

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.11.10 hook-env	20.0 ± 0.6	18.4	22.4	1.01 ± 0.05
mise hook-env	19.9 ± 0.9	18.4	21.9	1.00

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.11.10 ls	17.0 ± 0.6	15.8	18.7	1.00
mise ls	17.6 ± 0.8	15.6	19.2	1.03 ± 0.06

xtasks/test/perf

Command	mise-2025.11.10	mise	Variance
install (cached)	109ms	111ms	-1%
ls (cached)	65ms	68ms	-4%
bin-paths (cached)	72ms	72ms	+0%
task-ls (cached)	432ms	450ms	-4%