ctest: Revise generate function to return Result #4430

Owen-CH-Leung · 2025-04-26T14:47:33Z

Description

As per #4369 , the generate function should return a Result instead of returning nothing.

This PR is a continuation of #4424 which was closed due to bad rebase.

Checklist

Relevant tests in libc-test/semver have been updated
No placeholder or unstable values like *LAST or *MAX are
included (see rust-lang/libc#3131)
Tested locally (cd libc-test && cargo test --target mytarget);
especially relevant for platforms that may not be checked in CI

rustbot · 2025-04-26T14:47:37Z

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tgross35 · 2025-04-28T22:33:24Z

ctest/src/lib.rs

 use std::fs::File;
 use std::io::prelude::*;
 use std::io::BufWriter;
+use std::panic::{catch_unwind, AssertUnwindSafe};


Unfortunately we can't use catch_unwind; if somebody has panic = abort in their Cargo.toml or if run on a target/backend that doesn't support unwinding, the program will stop and catch_unwind won't actually catch anything. All functions that may return an error need to change their signature then update .unwrap() / .expect() to ?.

Everything else looks pretty good to me, but I'll re-review after the changes.

(basically my same comment from #4424 (comment))

Thanks. I've removed the remaining catch_unwind logic.

tgross35

Looks much better! I left a few more comments.

tgross35 · 2025-05-03T06:17:42Z

ctest/src/lib.rs

+        match cfg.try_compile(&format!("lib{stem}.a")) {
+            Ok(_) => Ok(out),
+            Err(e) => Err(anyhow::anyhow!("Compilation failed").context(format!("Error: {}", e))),
+        }


I think the error handling could be a bit simplified here:

let name = format!("lib{stem}.a"); cfg.try_compile(&name) .context("failed to compile `{name}`")? .map(|()| out)

tgross35 · 2025-05-03T06:19:46Z

ctest/src/lib.rs

+        // Check if all specified header files exist in the include paths
+        for header in &self.headers {
+            // Check if header exists in any of the include paths
+            for include_path in &self.includes {
+                let header_path = include_path.join(header);
+                if !header_path.exists() {
+                    return Err(anyhow::anyhow!("Header file not found"))
+                        .with_context(|| format!("Path {} does not exist", header_path.display()));
+                }
+            }
+        }


Where do the header files actually get read? There is a TOCTOU error here (albeit mild). It would be better to just add an error message wherever they are opened, and this block can be removed.

Indeed. I've removed this block. Thanks!

tgross35 · 2025-05-03T06:21:38Z

ctest/src/lib.rs

+        if !out_dir.is_dir() {
+            return Err(anyhow::anyhow!(
+                "Output directory does not exist: {}",
+                out_dir.display()
+            ));
+        }


Similar to the above, we shouldn't really need this check.

Sure & removed

tgross35 · 2025-05-03T06:25:44Z

ctest/src/lib.rs

+            let diag_info = format!("{:?}", d);
+            // Emit the diagnostic to properly handle it and show error to the user
+            d.emit();
+            anyhow::anyhow!("failed to parse crate").context(format!("Diagnostic: {}", diag_info))


d.emit(); anyhow!("failed to parse crate: {d:?}")

No need to put the diagnostic in context since it goes with the error, or to format! it separately. Also you can import anyhow::anyhow since it's used a few times.

Actually, why .emit() the diagnostic at all? Does that give different output compared to printing it with either Debug or Display?

the emit() is necessary becoz without the emit call, the DiagnosticBuilder will panic on drop:

https://github.com/JohnTitor/garando/blob/master/garando_errors/src/diagnostic_builder.rs#L157

Owen-CH-Leung · 2025-05-04T12:29:27Z

Looks like there is a flaky test :

https://github.com/rust-lang/libc/runs/41604457695

I re-trigger the CI and it passes

tgross35

LGTM! We can update more .unwrap() to proper errors later. Please squash.

…Add anyhow error handling. Revert expect call in generate API Add missing impl. rustfmt & clippy Remove leftovers Fix linking error due to use of OsString Remove panic_payload_to_string. Remove catch_unwind Emit Diagnostic Error before mapping to anyhow Trigger CI again Remove header file check and out_dir check Trigger CI again

Owen-CH-Leung · 2025-05-13T10:25:59Z

LGTM! We can update more .unwrap() to proper errors later. Please squash.

Done :)

tgross35

Thanks for the work here!

rustbot assigned tgross35 Apr 26, 2025

rustbot added ctest Issues relating to the ctest crate S-waiting-on-review labels Apr 26, 2025

Owen-CH-Leung marked this pull request as ready for review April 27, 2025 00:39

tgross35 requested changes Apr 28, 2025

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rustbot added S-waiting-on-author and removed S-waiting-on-review labels Apr 28, 2025

tgross35 reviewed May 3, 2025

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tgross35 changed the title ~~Revise generate function to return Result~~ ctest: Revise generate function to return Result May 4, 2025

Owen-CH-Leung requested a review from tgross35 May 11, 2025 09:01

rustbot added S-waiting-on-review and removed S-waiting-on-author labels May 11, 2025

tgross35 approved these changes May 12, 2025

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tgross35 added the stable-unneeded This PR is applied to main but already exists on libc-0.2 label May 12, 2025

Owen-CH-Leung force-pushed the add_try_generate_signature branch from 586da1b to c54f1b9 Compare May 13, 2025 10:25

tgross35 approved these changes May 13, 2025

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tgross35 added this pull request to the merge queue May 13, 2025

github-merge-queue bot removed this pull request from the merge queue due to failed status checks May 13, 2025

tgross35 added this pull request to the merge queue May 13, 2025

Merged via the queue into rust-lang:main with commit 76696a2 May 13, 2025
48 of 50 checks passed

ctest: Revise generate function to return Result #4430

ctest: Revise generate function to return Result #4430

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Owen-CH-Leung commented May 4, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Owen-CH-Leung commented May 13, 2025

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Owen-CH-Leung commented Apr 26, 2025 •

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