feat: Improve error for install with specific version

[kenoss]

Option 1 of #189

---

Before this patch, moonup install <specific-version> fails with an simple error:

$ moonup install 0.9.3
No toolchain available for requested spec '0.9.3'

This patch improves the error, showing available versions near to the given version:

$ moonup install 0.9.3
  x no release available for requested spec: 0.9.3. hint: e.g. 0.9.3+08f337e2c is available.

---

Note that I'm using aarch64 Linux and I need tweaks to run tests. I checked that the test passes in my environment, but it might fail.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 050527aa-ef79-4cc5-a7ea-1ca708ea5d70

📥 Commits

Reviewing files that changed from the base of the PR and between 83d9a87 and 7b84527.

⛔ Files ignored due to path filters (1)

• tests/e2e/snapshots/test__e2e__flow__moonup_install_specific_version_unavailable_mock.snap is excluded by !**/*.snap

📒 Files selected for processing (1)

• src/toolchain/index.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• src/toolchain/index.rs

---

Summary by CodeRabbit

• Bug Fixes
  • Improved toolchain install and update error handling so unavailable releases/versions return clear, actionable messages instead of abrupt failures.
  • For requested toolchain versions, the app now performs exact matching and—when no exact match exists—suggests nearby available versions.
• New Features
  • Enhanced version resolution logic for install/update flows, including improved handling of nightly and release requests.
• Tests
  • Added an additional end-to-end snapshot assertion for installing an unavailable specific version using the mocked dist server.

Walkthrough

This PR changes build_installrecipe to return InstallRecipe directly, adds error reporting for missing supported releases, and updates the install/update commands to propagate those errors. The e2e flow adds a snapshot for an unavailable specific-version install. regex was moved into the main dependencies table.

Changes

Toolchain recipe errors

Layer / File(s)	Summary
Recipe return type and missing-host errors src/toolchain/index.rs	build_installrecipe returns InstallRecipe directly, and unsupported Bleeding/Latest/Nightly specs now return miette errors instead of None.
Version parsing and hinting Cargo.toml, src/toolchain/index.rs	regex moves into the main dependency table, and version-based recipe lookup now parses supported releases, sorts them, binary-searches exact matches, and includes nearby-version hints when no match is found.
CLI propagation and install snapshot src/cli/install.rs, src/cli/update.rs, tests/e2e/flow.rs	moonup install and moonup update now propagate build_installrecipe failures, and the e2e flow adds a snapshot for installing version 0.1 against the mocked dist server.

Possibly related issues

• chawyehsu/moonup#189 — The PR updates build_installrecipe, moonup install, and the version-selection path to emit clearer unavailable-version errors and adds a snapshot for that specific-version case.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[coderabbitai]

Actionable comments posted: 2

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: a0f5263b-984c-4536-af05-4ea61bfaee07

📥 Commits

Reviewing files that changed from the base of the PR and between 1af68b2 and 83d9a87.

⛔ Files ignored due to path filters (1)

• tests/e2e/snapshots/test__e2e__flow__moonup_install_specific_version_unavailable_mock.snap is excluded by !**/*.snap

📒 Files selected for processing (5)

• Cargo.toml
• src/cli/install.rs
• src/cli/update.rs
• src/toolchain/index.rs
• tests/e2e/flow.rs

[chawyehsu]

I'd love to place the hint to a new line. This way, when we add other hints later, we can keep all hints in the same format.

$ moonup install 0.9.3
No release available for requested spec '0.9.3'

Hint: 0.9.3+08f337e2c is available

[kenoss]

Updated. Two versions:

commit 916de59 (with \n\n)

$ cargo run --bin moonup -- install 0.9.3
  x No release available for requested spec: 0.9.3.
  |
  | Hint: 0.9.3+08f337e2c is available.

commit 7b84527 (with MietteDiagnostic::with_help())

$ cargo run --bin moonup -- install 0.9.3
  x No release available for requested spec: 0.9.3.
  help: 0.9.2+bbe2b338f and 0.9.3+08f337e2c are available.

Note that there is no hint field in miette::Diagnostic and we need to use help. We can use custom handlers to modify format.

Which one is better? Also, let me know if we use squash for commit.

---

I'll fix #191 first as the test for aarch64 is failing.

[stage-review]

Ready to review this PR? Stage has broken it down into 3 individual chapters for you:

	Title
1	Promote regex to a core dependency
2	Enhance version resolution with helpful error hints
3	Other changes

_{Chapters generated by Stage for commit 7b84527 on Jun 29, 2026 3:23am UTC.}