feat(backend): improve http error when platform url missing; list available platforms

[jdx]

• Improve error when no 'url' and no matching platform URL
• Show available platforms detected from options
• Helper moved to backend/static_helpers.rs and reused

This enhances UX by pointing users to valid platform keys when the current platform is unsupported.

[Copilot]

Pull Request Overview

This PR improves the HTTP backend error handling by providing more helpful error messages when platform URLs are missing. It enhances user experience by listing available platforms when the current platform is unsupported, and consolidates shared OS/arch pattern logic into a reusable helper module.

• Enhanced error message in HTTP backend to show available platforms when URL is missing
• Added helper function to list available platforms with specific keys
• Moved and shared OS/arch patterns to reduce code duplication

Reviewed Changes

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

File	Description
src/toolset/tool_version_options.rs	Added iterator method for accessing tool version options
src/backend/static_helpers.rs	Added shared OS/arch patterns and new function to list available platforms
src/backend/http.rs	Enhanced error message to show available platforms when URL missing

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[Copilot]

The iterator returns references to String rather than string slices. Consider returning impl Iterator<Item = (&str, &str)> for better ergonomics and to avoid unnecessary String allocations in consumer code.

Suggested change

	pub fn iter(&self) -> impl Iterator<Item = (&String, &String)> {
	self.opts.iter()
	pub fn iter(&self) -> impl Iterator<Item = (&str, &str)> {
	self.opts.iter().map(|(k, v)| (k.as_str(), v.as_str()))

[Copilot]

This function has extensive inline comments but lacks a proper docstring. Consider adding a doc comment that describes the function's purpose, parameters, return value, and provides examples of the platform key formats it supports.

Suggested change

	/// Lists platform keys (e.g. "macos-x64") for which a given key_type exists (e.g. "url").
	/// Supports both nested TOML (platforms.<os>-<arch>.<key_type>) and flat keys
	/// (platforms_<os>_<arch>_<key_type>). Avoids parsing TOML inline; relies on
	/// ToolVersionOptions nested key handling.
	/// Returns a list of platform keys (e.g. `"macos-x64"`, `"linux-arm64"`) for which a given `key_type` (such as `"url"`) exists in the provided `ToolVersionOptions`.
	///
	/// This function supports both nested TOML keys and flat keys:
	/// - **Nested format:** `platforms.<os>-<arch>.<key_type>` or `platform.<os>-<arch>.<key_type>`
	/// - Example: `platforms.macos-x64.url`, `platform.linux-arm64.checksum`
	/// - **Flat format:** `platforms_<os>_<arch>_<key_type>` or `platform_<os>_<arch>_<key_type>`
	/// - Example: `platforms_macos_x64_url`, `platform_linux_arm64_checksum`
	///
	/// # Parameters
	/// - `opts`: Reference to a `ToolVersionOptions` containing the key-value pairs to search.
	/// - `key_type`: The type of value to look for (e.g., `"url"`, `"checksum"`).
	///
	/// # Returns
	/// A vector of platform keys (in `<os>-<arch>` format) for which the specified `key_type` exists.
	///
	/// # Examples
	/// Given the following keys in `opts`:
	/// - `platforms.macos-x64.url`
	/// - `platforms_linux_x64_url`
	/// - `platform.windows-x64.checksum`
	///
	/// Calling `list_available_platforms_with_key(opts, "url")` will return:
	/// - `"macos-x64"`
	/// - `"linux-x64"`
	///
	/// Calling `list_available_platforms_with_key(opts, "checksum")` will return:
	/// - `"windows-x64"`

[cursor]

Bug: Key Parsing Error Causes Architecture Name Mismatch

The flat key parsing in list_available_platforms_with_key incorrectly converts all underscores to dashes when generating platform keys. This corrupts architecture names like x86_64 to x86-64, leading to mismatches with expected platform keys and incorrect suggestions.

 

[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.2 x -- echo	20.0 ± 1.6	18.0	28.1	1.04 ± 0.10
mise x -- echo	19.2 ± 1.0	18.0	25.2	1.00

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.2 env	18.1 ± 1.0	17.4	31.1	1.00
mise env	18.5 ± 7.3	17.4	176.8	1.02 ± 0.41

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.2 hook-env	17.5 ± 0.4	17.1	23.6	1.00 ± 0.03
mise hook-env	17.4 ± 0.2	17.0	18.8	1.00

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.2 ls	16.0 ± 0.5	15.4	22.5	1.00
mise ls	16.0 ± 0.4	15.5	21.1	1.00 ± 0.04

xtasks/test/perf

Command	mise-2025.9.2	mise	Variance
install (cached)	165ms	✅ 100ms	+65%
ls (cached)	61ms	62ms	-1%
bin-paths (cached)	65ms	66ms	-1%
task-ls (cached)	477ms	481ms	+0%

✅ Performance improvement: install cached is 65%