Vendor narinfo-related logic

[cole-h]

So we don't have to depend on attic-server for "just" this.

Summary by CodeRabbit

• Refactor

  • Restructured internal module organization for improved code maintainability and Nix cache manifest handling.

• Chores

  • Updated dependencies to support enhanced serialization performance.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: db0fe62e-784f-49a5-9371-ecc898f48f28

📥 Commits

Reviewing files that changed from the base of the PR and between 3ab0168 and bd6e350.

⛔ Files ignored due to path filters (1)

• Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (6)

• magic-nix-cache/Cargo.toml
• magic-nix-cache/src/gha.rs
• magic-nix-cache/src/main.rs
• magic-nix-cache/src/narinfo/mod.rs
• magic-nix-cache/src/narinfo/nix_manifest/mod.rs
• magic-nix-cache/src/narinfo/nix_manifest/serializer.rs

✅ Files skipped from review due to trivial changes (2)

• magic-nix-cache/src/main.rs
• magic-nix-cache/Cargo.toml

🚧 Files skipped from review as they are similar to previous changes (3)

• magic-nix-cache/src/narinfo/nix_manifest/serializer.rs
• magic-nix-cache/src/narinfo/nix_manifest/mod.rs
• magic-nix-cache/src/narinfo/mod.rs

---

📝 Walkthrough

Walkthrough

This pull request extracts Nix binary cache manifest (.narinfo) handling from the attic-server dependency into a local module with custom Serde-based serialization support, removing the external dependency while adding internal serialization utilities.

Changes

Cohort / File(s)	Summary
Dependency Updates Cargo.toml	Removed attic-server git dependency; added serde_with, itoa, and ryu crates.
Module Declaration src/main.rs	Added new narinfo module declaration.
NarInfo Structures src/narinfo/mod.rs	Introduced NarInfo struct and Compression enum with Serde support, mapping Nix manifest key names to Rust struct fields with space-delimited references list handling.
Custom Serializer Foundation src/narinfo/nix_manifest/mod.rs	Added public to_string() utility function, SpaceDelimitedList type alias, and custom Error enum for serialization support.
Serializer Implementation src/narinfo/nix_manifest/serializer.rs	Implemented custom Serializer struct with Serde trait implementations to render values as compact key-value text format, using itoa for integers and ryu for floats.
Import Updates src/gha.rs	Switched Compression and NarInfo imports from attic_server::narinfo to crate::narinfo; simplified error handling in upload_path.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~22 minutes

Poem

🐰 A cache of manifests, once borrowed, now grown—
From attic's far branches to gardens we've sown,
With serializers spinning and formats so tight,
The narinfo dances in Serde's delight! ✨
One module, self-sovereign, no imports to beg,
We hop forward proudly on our own sturdy leg!

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Vendor narinfo-related logic' clearly and concisely summarizes the main change: moving narinfo parsing/serialization code into the project instead of depending on attic-server.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch vendor-narinfo-logic

---

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[coderabbitai]

Actionable comments posted: 6

🧹 Nitpick comments (1)

magic-nix-cache/src/narinfo/mod.rs (1)

182-186: Prefer implementing Display instead of ToString.

Implementing Display is more idiomatic in Rust and provides ToString automatically via blanket impl. This also enables use with format!, println!, etc.

♻️ Proposed refactor

-impl ToString for Compression {
-    fn to_string(&self) -> String {
-        String::from(self.as_str())
+impl std::fmt::Display for Compression {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.as_str())
     }
 }

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@magic-nix-cache/src/narinfo/mod.rs` around lines 182 - 186, The impl ToString
for Compression should be replaced with an impl std::fmt::Display for
Compression so the type implements fmt::Display (enabling format!, println!,
etc.) and ToString is provided automatically; update the impl block for
Compression to implement fmt::Display by adding fn fmt(&self, f: &mut
std::fmt::Formatter) -> std::fmt::Result that writes self.as_str() to the
formatter using write!(f, "{}", self.as_str()) (remove the existing impl
ToString block).

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@magic-nix-cache/src/narinfo/mod.rs`:
- Line 107: Fix the typo in the doc comment that currently reads "Other store
paths this object directly refereces." — change "refereces" to "references" in
the comment string in magic-nix-cache::narinfo::mod.rs (the doc comment line
"Other store paths this object directly refereces.").

In `@magic-nix-cache/src/narinfo/nix_manifest/deserializer.rs`:
- Around line 143-146: Remove the debug eprintln! in the closure that handles
missing colon: in deserializer.rs where you compute let colon =
line.find(':').ok_or_else(|| { eprintln!("Current input: {:?}", self.input);
Error::ExpectedColon })?; drop the eprintln!("Current input: {:?}", self.input)
and simplify the closure to just return Error::ExpectedColon (i.e.,
ok_or_else(|| Error::ExpectedColon)), leaving the rest of the logic unchanged;
references: colon, line.find, self.input, Error::ExpectedColon.
- Line 10: The deserializer (deserializer.rs) refers to Error enum variants that
don't exist, causing compilation failures; update the Error enum (Error) to
include the missing variants referenced by the deserializer: UnexpectedEof,
ExpectedInteger, ExpectedBoolean, ExpectedColon, FloatUnsupported, and
Unexpected, making sure each variant name matches exactly what deserializer.rs
uses (and keep existing variants Unsupported, NoneUnsupported,
NestedMapUnsupported, Custom); add appropriate variants (plain or with payloads
if deserializer expects data) so the code compiles and error handling remains
consistent with the deserializer's usage.

In `@magic-nix-cache/src/narinfo/nix_manifest/mod.rs`:
- Line 91: Fix the typo in the Display/format implementation for the Error
variant NestedMapUnsupported: change the message string used in the match arm
for Error::NestedMapUnsupported (currently "Nexted maps are unsupported.") to
the correct "Nested maps are unsupported." so the error text is spelled
correctly when formatting errors.
- Around line 37-53: The doc example references the old path
attic_server::nix_manifest which is stale; update the hidden use to the current
module path by replacing that import with crate::narinfo::nix_manifest::{self,
SpaceDelimitedList} (so the example imports SpaceDelimitedList and
nix_manifest::from_str from the correct location), or alternatively mark the
example as ignored if you don't want it run as a doctest; update the reference
near the example that mentions SpaceDelimitedList and from_str accordingly.
- Line 21: The crate exposes serialization via mod.rs but the deserialization
implementation (deserializer.rs) and its public function from_str are not
exposed, causing the documented example nix_manifest::from_str(s) to be
unreachable; either add a module declaration such as pub mod deserializer; in
mod.rs to publicly expose deserializer::from_str (and update pub re-exports if
you want it at the crate root), or remove/adjust the documentation example and
any public API surface that references from_str if deserialization should remain
internal; ensure references to deserializer, from_str, and mod.rs are updated
consistently.

---

Nitpick comments:
In `@magic-nix-cache/src/narinfo/mod.rs`:
- Around line 182-186: The impl ToString for Compression should be replaced with
an impl std::fmt::Display for Compression so the type implements fmt::Display
(enabling format!, println!, etc.) and ToString is provided automatically;
update the impl block for Compression to implement fmt::Display by adding fn
fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result that writes
self.as_str() to the formatter using write!(f, "{}", self.as_str()) (remove the
existing impl ToString block).

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 50ea3c5b-121e-451c-89ee-d9916c9ef47c

📥 Commits

Reviewing files that changed from the base of the PR and between 628eb14 and 3ab0168.

⛔ Files ignored due to path filters (1)

• Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (7)

• magic-nix-cache/Cargo.toml
• magic-nix-cache/src/gha.rs
• magic-nix-cache/src/main.rs
• magic-nix-cache/src/narinfo/mod.rs
• magic-nix-cache/src/narinfo/nix_manifest/deserializer.rs
• magic-nix-cache/src/narinfo/nix_manifest/mod.rs
• magic-nix-cache/src/narinfo/nix_manifest/serializer.rs