don't cache external job failures if they could be caused by the user killing processes

crates/fayalite/src/build/external.rs

@@ -12,7 +12,7 @@ use crate::{
 };
 use base64::{Engine, prelude::BASE64_URL_SAFE_NO_PAD};
 use clap::builder::OsStringValueParser;
-use eyre::{Context, bail, ensure, eyre};
+use eyre::{Context, ensure, eyre};
 use serde::{
     Deserialize, Deserializer, Serialize, Serializer,
     de::{DeserializeOwned, Error},
@@ -26,6 +26,7 @@ use std::{
     io::Write,
     marker::PhantomData,
     path::{Path, PathBuf},
+    process::ExitStatus,
     sync::OnceLock,
 };
 
@@ -365,13 +366,17 @@ impl ExternalJobCaching {
             .stdin(std::process::Stdio::null());
         Ok(cmd)
     }
-    pub fn run<F: FnOnce(std::process::Command) -> eyre::Result<()>>(
+    pub fn run<F>(
         self,
         command_line: Interned<[Interned<OsStr>]>,
         input_file_paths: impl IntoIterator<Item = Interned<Path>>,
         output_file_paths: impl IntoIterator<Item = Interned<Path>> + Clone,
         run_fn: F,
-    ) -> eyre::Result<()> {
+        exit_status_to_error: impl FnOnce(ExitStatus) -> eyre::Report,
+    ) -> eyre::Result<()>
+    where
+        F: FnOnce(std::process::Command) -> eyre::Result<Result<(), ExitStatus>>,
+    {
         let mut hasher = JobCacheHasher::default();
         hasher.hash_iter(command_line.iter(), |hasher, arg| {
             hasher.hash_sized_os_str(arg)
@@ -419,7 +424,26 @@ impl ExternalJobCaching {
                 })
                 .expect("spawn shouldn't fail");
             run_fn(cmd)
-        });
+        })?;
+        if let Err(exit_status) = result {
+            // check if the user may have terminated it or something, don't cache the failure
+            let user_maybe_terminated;
+            #[cfg(unix)]
+            {
+                user_maybe_terminated = std::os::unix::process::ExitStatusExt::signal(&exit_status)
+                    .is_some()
+                    || exit_status.code().is_none_or(|code| code > 1);
+            }
+            #[cfg(not(unix))]
+            {
+                user_maybe_terminated = !exit_status.success();
+            }
+            if user_maybe_terminated {
+                let _ = std::fs::remove_file(self.cache_json_path);
+                return Err(exit_status_to_error(exit_status));
+            }
+        }
+        let result = result.map_err(exit_status_to_error);
         ExternalJobCacheV2 {
             version: ExternalJobCacheVersion::CURRENT,
             inputs_hash,
@@ -444,16 +468,26 @@ impl ExternalJobCaching {
         .write_to_file(self.cache_json_path)?;
         result
     }
-    pub fn run_maybe_cached<F: FnOnce(std::process::Command) -> eyre::Result<()>>(
+    pub fn run_maybe_cached<F>(
         this: Option<Self>,
         command_line: Interned<[Interned<OsStr>]>,
         input_file_paths: impl IntoIterator<Item = Interned<Path>>,
         output_file_paths: impl IntoIterator<Item = Interned<Path>> + Clone,
         run_fn: F,
-    ) -> eyre::Result<()> {
+        exit_status_to_error: impl FnOnce(ExitStatus) -> eyre::Report,
+    ) -> eyre::Result<()>
+    where
+        F: FnOnce(std::process::Command) -> eyre::Result<Result<(), ExitStatus>>,
+    {
         match this {
-            Some(this) => this.run(command_line, input_file_paths, output_file_paths, run_fn),
-            None => run_fn(Self::make_command(command_line)?),
+            Some(this) => this.run(
+                command_line,
+                input_file_paths,
+                output_file_paths,
+                run_fn,
+                exit_status_to_error,
+            ),
+            None => run_fn(Self::make_command(command_line)?)?.map_err(exit_status_to_error),
         }
     }
 }
@@ -1119,10 +1153,12 @@ impl<T: ExternalCommand> JobKind for ExternalCommandJobKind<T> {
                 }
                 let status = acquired_job.run_command(cmd, |cmd| cmd.status())?;
                 if !status.success() {
-                    bail!("running {command_line:?} failed: {status}")
+                    Ok(Err(status))
+                } else {
+                    Ok(Ok(()))
                 }
-                Ok(())
             },
+            |status| eyre!("running {command_line:?} failed: {status}"),
         )?;
         Ok(job
             .output_paths()