Add a new "fix" mode

This introduces a new "fix" mode to run `cargo fix`. This is primarily
intended to support edition migration testing.

This includes two related changes:

- Adds the ability to change the CapLints behavior because setting
  CapLints interferes with how `cargo fix` works.
- Sets the mount mode of the source directory to read-write because
  `cargo fix` inherently needs to be able to write to the source
  directory.

It probably needs more work for general purpose `cargo fix` testing
(non-edition) because otherwise it would need to rebuild the source
directory between toolchains. I don't need that right now, so deferred
that till later.

Author: ehuss

docs/bot-usage.md

@@ -85,6 +85,7 @@ The following experiment modes are currently available:
 * `check-only`: run `cargo check` on every crate (faster)
 * `clippy`: run `cargo clippy` on every crate
 * `rustdoc`: run `cargo doc --no-deps` on every crate
+* `fix`: run `cargo fix` on every crate (intended for edition migration testing)
 
 The mode you should use depends on what your experiment is testing:
 

src/experiments.rs

@@ -30,6 +30,7 @@ string_enum!(pub enum Mode {
     Clippy => "clippy",
     Rustdoc => "rustdoc",
     UnstableFeatures => "unstable-features",
+    Fix => "fix",
 });
 
 string_enum!(pub enum CapLints {

src/runner/tasks.rs

@@ -48,6 +48,7 @@ pub(super) enum TaskStep {
     Clippy { tc: Toolchain, quiet: bool },
     Rustdoc { tc: Toolchain, quiet: bool },
     UnstableFeatures { tc: Toolchain },
+    Fix { tc: Toolchain, quiet: bool },
 }
 
 impl fmt::Debug for TaskStep {
@@ -59,6 +60,7 @@ impl fmt::Debug for TaskStep {
             TaskStep::Clippy { ref tc, quiet } => ("clippy", quiet, Some(tc)),
             TaskStep::Rustdoc { ref tc, quiet } => ("doc", quiet, Some(tc)),
             TaskStep::UnstableFeatures { ref tc } => ("find unstable features on", false, Some(tc)),
+            TaskStep::Fix { ref tc, quiet } => ("fix", quiet, Some(tc)),
         };
 
         write!(f, "{name}")?;
@@ -124,6 +126,9 @@ impl Task {
                 tc,
                 false,
             ),
+            TaskStep::Fix { ref tc, quiet } => {
+                (&build_dir[tc], "fixing", test::fix, tc, quiet)
+            }
         };
 
         let ctx = TaskCtx::new(build_dir, config, ex, toolchain, &self.krate, quiet);

src/runner/test.rs

@@ -1,4 +1,5 @@
 use crate::crates::Crate;
+use crate::experiments::CapLints;
 use crate::prelude::*;
 use crate::results::DiagnosticCode;
 use crate::results::{BrokenReason, FailureReason, TestResult};
@@ -9,7 +10,7 @@ use cargo_metadata::diagnostic::DiagnosticLevel;
 use cargo_metadata::{Message, Metadata, Package, Target};
 use docsrs_metadata::Metadata as DocsrsMetadata;
 use remove_dir_all::remove_dir_all;
-use rustwide::cmd::{CommandError, ProcessLinesActions, SandboxBuilder};
+use rustwide::cmd::{CommandError, MountKind, ProcessLinesActions, SandboxBuilder};
 use rustwide::logging::LogStorage;
 use rustwide::{Build, PrepareError};
 use std::collections::{BTreeSet, HashMap, HashSet};
@@ -111,6 +112,8 @@ fn run_cargo(
     check_errors: bool,
     local_packages: &[Package],
     env: HashMap<&'static str, String>,
+    mount_kind: MountKind,
+    cap_lints: Option<CapLints>,
 ) -> Fallible<()> {
     let local_packages_id: HashSet<_> = local_packages.iter().map(|p| &p.id).collect();
 
@@ -122,13 +125,17 @@ fn run_cargo(
         args.extend(tc_cargoflags.split(' '));
     }
 
-    let mut rustflags = format!("--cap-lints={}", ctx.experiment.cap_lints.to_str());
+    let mut rustflags = cap_lints
+        .map(|cap| format!("--cap-lints={cap}"))
+        .unwrap_or_default();
     if let Some(ref tc_rustflags) = ctx.toolchain.rustflags {
         rustflags.push(' ');
         rustflags.push_str(tc_rustflags);
     }
 
-    let mut rustdocflags = format!("--cap-lints={}", ctx.experiment.cap_lints.to_str());
+    let mut rustdocflags = cap_lints
+        .map(|cap| format!("--cap-lints={cap}"))
+        .unwrap_or_default();
     if let Some(ref tc_rustdocflags) = ctx.toolchain.rustdocflags {
         rustdocflags.push(' ');
         rustdocflags.push_str(tc_rustdocflags);
@@ -209,6 +216,7 @@ fn run_cargo(
     let mut command = build_env
         .cargo()
         .args(&args)
+        .source_dir_mount_kind(mount_kind)
         .env("CARGO_INCREMENTAL", "0")
         .env("RUST_BACKTRACE", "full")
         .env("RUSTFLAGS", rustflags)
@@ -288,6 +296,8 @@ fn build(ctx: &TaskCtx, build_env: &Build, local_packages: &[Package]) -> Fallib
         true,
         local_packages,
         HashMap::default(),
+        MountKind::ReadOnly,
+        Some(ctx.experiment.cap_lints),
     )?;
     run_cargo(
         ctx,
@@ -296,6 +306,8 @@ fn build(ctx: &TaskCtx, build_env: &Build, local_packages: &[Package]) -> Fallib
         true,
         local_packages,
         HashMap::default(),
+        MountKind::ReadOnly,
+        Some(ctx.experiment.cap_lints),
     )?;
     Ok(())
 }
@@ -308,6 +320,8 @@ fn test(ctx: &TaskCtx, build_env: &Build) -> Fallible<()> {
         false,
         &[],
         HashMap::default(),
+        MountKind::ReadOnly,
+        Some(ctx.experiment.cap_lints),
     )
 }
 
@@ -361,6 +375,8 @@ pub(super) fn test_check_only(
         true,
         local_packages_id,
         HashMap::default(),
+        MountKind::ReadOnly,
+        Some(ctx.experiment.cap_lints),
     ) {
         Ok(TestResult::BuildFail(failure_reason(&err)))
     } else {
@@ -386,6 +402,8 @@ pub(super) fn test_clippy_only(
         true,
         local_packages,
         HashMap::default(),
+        MountKind::ReadOnly,
+        Some(ctx.experiment.cap_lints),
     ) {
         Ok(TestResult::BuildFail(failure_reason(&err)))
     } else {
@@ -399,7 +417,16 @@ pub(super) fn test_rustdoc(
     local_packages: &[Package],
 ) -> Fallible<TestResult> {
     let run = |cargo_args, env| {
-        let res = run_cargo(ctx, build_env, cargo_args, true, local_packages, env);
+        let res = run_cargo(
+            ctx,
+            build_env,
+            cargo_args,
+            true,
+            local_packages,
+            env,
+            MountKind::ReadOnly,
+            Some(ctx.experiment.cap_lints),
+        );
 
         // Make sure to remove the built documentation
         // There is no point in storing it after the build is done
@@ -458,6 +485,35 @@ fn is_library(target: &Target) -> bool {
             .all(|k| !["example", "test", "bench"].contains(&k.as_str()))
 }
 
+pub(crate) fn fix(
+    ctx: &TaskCtx,
+    build_env: &Build,
+    local_packages_id: &[Package],
+) -> Fallible<TestResult> {
+    if let Err(err) = run_cargo(
+        ctx,
+        build_env,
+        &[
+            "fix",
+            "--allow-no-vcs",
+            "--allow-dirty",
+            "--frozen",
+            "--all",
+            "--all-targets",
+            "--message-format=json",
+        ],
+        true,
+        local_packages_id,
+        HashMap::default(),
+        MountKind::ReadWrite,
+        None,
+    ) {
+        Ok(TestResult::BuildFail(failure_reason(&err)))
+    } else {
+        Ok(TestResult::TestPass)
+    }
+}
+
 #[test]
 fn test_failure_reason() {
     let error: anyhow::Error = anyhow!(CommandError::IO(std::io::Error::other("Test")));

src/runner/worker.rs

@@ -123,7 +123,8 @@ impl<'a> Worker<'a> {
                     | TaskStep::CheckOnly { tc, .. }
                     | TaskStep::Clippy { tc, .. }
                     | TaskStep::Rustdoc { tc, .. }
-                    | TaskStep::UnstableFeatures { tc } => Some(tc),
+                    | TaskStep::UnstableFeatures { tc }
+                    | TaskStep::Fix { tc, .. } => Some(tc),
                 };
                 if let Some(toolchain) = toolchain {
                     if toolchain == self.ex.toolchains.last().unwrap() {
@@ -302,6 +303,10 @@ impl<'a> Worker<'a> {
                             quiet,
                         },
                         Mode::UnstableFeatures => TaskStep::UnstableFeatures { tc: tc.clone() },
+                        Mode::Fix => TaskStep::Fix {
+                            tc: tc.clone(),
+                            quiet,
+                        }
                     },
                 };
 

src/server/routes/ui/experiments.rs

@@ -41,6 +41,7 @@ impl ExperimentData {
                 Mode::Clippy => "cargo clippy",
                 Mode::Rustdoc => "cargo doc",
                 Mode::UnstableFeatures => "unstable features",
+                Mode::Fix => "cargo fix",
             },
             assigned_to: experiment.assigned_to.as_ref().map(|a| a.to_string()),
             priority: experiment.priority,