feat(minvmd): T01 — crate scaffold, libkrun FFI wrappers, smoke test - #236

docs/specs/01-spec-minvmd-host-daemon/01-spec-minvmd-host-daemon.md (2)

134-139: 💤 Low value

Add language specifier to code block for better rendering.

The process model diagram is in a fenced code block without a language specifier. Adding text or plaintext would improve rendering and satisfy markdown linters.

📝 Proposed formatting fix

-```
+```text
 minvmd run                       (parent — supervisor)

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@docs/specs/01-spec-minvmd-host-daemon/01-spec-minvmd-host-daemon.md` around
lines 134 - 139, Update the fenced code block containing the process model
diagram (the block showing "minvmd run", "minvmd __krun-vmm", "libkrun + Alpine
VM", "minimald (pid-1)") to include a language specifier such as text or
plaintext (e.g., replace ``` with ```text) so Markdown renders it correctly and
markdown linters accept it.

---

182-187: 💤 Low value

Surround verification table with blank lines.

Markdown best practices require tables to be surrounded by blank lines for proper parsing and rendering.

📝 Proposed formatting fix

Add a blank line before line 182 (| Check | Command |).

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@docs/specs/01-spec-minvmd-host-daemon/01-spec-minvmd-host-daemon.md` around
lines 182 - 187, The Markdown table starting with the header "| Check | Command
|" needs blank lines before and after it to follow Markdown parsing best
practices; edit the docs block that contains the table by inserting an empty
line immediately before the line containing "| Check | Command |" and another
empty line immediately after the final table row so the table is surrounded by
blank lines.

crates/minvmd/src/krun/ctx.rs (1)

93-96: ⚡ Quick win

Prefer Option combinators over enum-rebuilding match blocks.

These matches rebuild Option directly and can be simplified with combinators for consistency.

♻️ Proposed refactor

-        let envp_cstrs: Option<Vec<CString>> = match envp {
-            Some(entries) => Some(cstrings_from_strs(entries, "envp")?),
-            None => None,
-        };
+        let envp_cstrs: Option<Vec<CString>> =
+            envp.map(|entries| cstrings_from_strs(entries, "envp")).transpose()?;
...
-        let initramfs_cstr = match initramfs {
-            Some(p) => Some(cstring_from_path(p.as_ref(), "initramfs")?),
-            None => None,
-        };
-        let cmdline_cstr = match cmdline {
-            Some(s) => Some(cstring_from_str(s, "cmdline")?),
-            None => None,
-        };
+        let initramfs_cstr = initramfs
+            .map(|p| cstring_from_path(p.as_ref(), "initramfs"))
+            .transpose()?;
+        let cmdline_cstr = cmdline
+            .map(|s| cstring_from_str(s, "cmdline"))
+            .transpose()?;

As per coding guidelines, "Use combinators on Option/Result (map, and_then, ok_or, unwrap_or_else, map_err) instead of match expressions that reconstruct the same enum".

Also applies to: 148-155

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/minvmd/src/krun/ctx.rs` around lines 93 - 96, The match that
reconstructs envp_cstrs should be replaced with an Option combinator: call
envp.map(|entries| cstrings_from_strs(entries, "envp")).transpose()/map(|e| ...
) as appropriate so you don't rebuild the Option via match; update the analogous
match at lines 148-155 (e.g., argv_cstrs / cstrings_from_strs usage) to use the
same Option combinator pattern (map/and_then/transpose) to simplify and follow
the guideline.

crates/minvmd/src/bin/krun_smoke_child.rs (1)

44-44: ⚡ Quick win

Use captured identifier formatting for consistency.

Switch to captured formatting to match the Rust style guideline.

✏️ Proposed change

-    eprintln!("STAGE: create_ctx ok ctx_id={}", ctx.id());
+    eprintln!("STAGE: create_ctx ok ctx_id={}", ctx.id());

// Better:
eprintln!("STAGE: create_ctx ok ctx_id={ctx_id}");

As per coding guidelines, "Use captured-identifier formatting in format strings: format!("{path}") over format!("{}", path)".

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/minvmd/src/bin/krun_smoke_child.rs` at line 44, The eprintln uses
positional formatting with ctx.id(); instead, bind the id to a local identifier
and use captured-identifier formatting: create a let ctx_id = ctx.id();
(referencing ctx.id()) and change the eprintln call to use the captured {ctx_id}
in the format string (eprintln!("STAGE: create_ctx ok ctx_id={ctx_id}")),
keeping the same message and using the existing ctx and eprintln symbols.