refactor to replace results with panics where they represent system inconsistency errors

databuild/build_event_log.rs

@@ -164,7 +164,7 @@ impl<S: BELStorage + Debug> BuildEventLog<S> {
     }
 
     pub fn append_event(&mut self, event: &Event) -> Result<u64, DatabuildError> {
-        let events = self.state.handle_event(&event)?;
+        let events = self.state.handle_event(&event);
         let idx = self.storage.append_event(event)?;
         // Recursion here might be dangerous, but in theory the event propagation always terminates
         for event in events {

databuild/build_state.rs

@@ -1,7 +1,7 @@
 use crate::data_build_event::Event;
 use crate::data_deps::{WantTimestamps, missing_deps_to_want_events};
 use crate::partition_state::Partition;
-use crate::util::{DatabuildError, current_timestamp};
+use crate::util::current_timestamp;
 use crate::want_state::{IdleState as WantIdleState, Want, WantWithState};
 use crate::{
     JobRunBufferEventV1, JobRunCancelEventV1, JobRunDetail, JobRunFailureEventV1,
@@ -550,7 +550,7 @@ impl BuildState {
 
     /// Handles reacting to events, updating state, and erroring if its an invalid state transition
     /// Event handlers can return vecs of events that will then be appended to the BEL
-    pub fn handle_event(&mut self, event: &Event) -> Result<Vec<Event>, DatabuildError> {
+    pub fn handle_event(&mut self, event: &Event) -> Vec<Event> {
         match event {
             // JobRun events
             Event::JobRunBufferV1(e) => self.handle_job_run_buffer(e),
@@ -573,7 +573,7 @@ impl BuildState {
     fn handle_want_create(
         &mut self,
         event: &WantCreateEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
         // Use From impl to create want in Idle state
         let want_idle: WantWithState<WantIdleState> = event.clone().into();
         self.wants
@@ -584,13 +584,13 @@ impl BuildState {
             self.add_want_to_partition(pref, &event.want_id);
         }
 
-        Ok(vec![])
+        vec![]
     }
 
     fn handle_want_cancel(
         &mut self,
         event: &WantCancelEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
         // TODO actually cancel in-progress job runs that no longer have a sponsoring want
 
         // Type-safe transition (API layer should prevent canceling terminal wants)
@@ -623,91 +623,93 @@ impl BuildState {
         };
         self.wants.insert(event.want_id.clone(), canceled);
 
-        Ok(vec![])
+        vec![]
     }
 
     fn handle_job_run_buffer(
         &mut self,
         event: &JobRunBufferEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
-        // No job run should exist
+        // No job run should exist - if it does, that's a BUG in the orchestrator
         if self.job_runs.get(&event.job_run_id).is_some() {
-            Err(format!("Job run ID collision on job run ID {}", event.job_run_id).into())
+            panic!(
-        } else {
+                "BUG: Job run ID collision on job run ID {}. Orchestrator should generate unique IDs.",
-            // Create job run to be inserted
+                event.job_run_id
-            let job_run: JobRunDetail = event.clone().into();
+            );
-
-            // Transition wants to Building
-            // Valid states when job buffer event arrives:
-            // - Idle: First job starting for this want (normal case)
-            // - Building: Another job already started for this want (multiple jobs can service same want)
-            // Invalid states (panic - indicates orchestrator bug):
-            // - UpstreamBuilding: Not schedulable, waiting for dependencies
-            // - Successful/Failed/UpstreamFailed/Canceled: Terminal states, not schedulable
-            for wap in &job_run.servicing_wants {
-                let want = self.wants.remove(&wap.want_id).expect(&format!(
-                    "BUG: Want {} must exist when job buffer event received",
-                    wap.want_id
-                ));
-
-                let transitioned = match want {
-                    Want::Idle(idle) => {
-                        // First job starting for this want
-                        Want::Building(idle.start_building(current_timestamp()))
-                    }
-                    Want::Building(building) => {
-                        // Another job already started, stay in Building (no-op)
-                        Want::Building(building)
-                    }
-                    _ => {
-                        panic!(
-                            "BUG: Want {} in invalid state {:?} for job buffer. Only Idle or Building wants should be scheduled.",
-                            wap.want_id, want
-                        );
-                    }
-                };
-
-                self.wants.insert(wap.want_id.clone(), transitioned);
-            }
-
-            // Transition partitions to Building state
-            self.transition_partitions_to_building(&job_run.building_partitions, &event.job_run_id);
-
-            self.job_runs
-                .insert(event.job_run_id.clone(), job_run.clone());
-            println!("Inserted job run: {:?}", job_run);
-            Ok(vec![])
         }
+
+        // Create job run to be inserted
+        let job_run: JobRunDetail = event.clone().into();
+
+        // Transition wants to Building
+        // Valid states when job buffer event arrives:
+        // - Idle: First job starting for this want (normal case)
+        // - Building: Another job already started for this want (multiple jobs can service same want)
+        // Invalid states (panic - indicates orchestrator bug):
+        // - UpstreamBuilding: Not schedulable, waiting for dependencies
+        // - Successful/Failed/UpstreamFailed/Canceled: Terminal states, not schedulable
+        for wap in &job_run.servicing_wants {
+            let want = self.wants.remove(&wap.want_id).expect(&format!(
+                "BUG: Want {} must exist when job buffer event received",
+                wap.want_id
+            ));
+
+            let transitioned = match want {
+                Want::Idle(idle) => {
+                    // First job starting for this want
+                    Want::Building(idle.start_building(current_timestamp()))
+                }
+                Want::Building(building) => {
+                    // Another job already started, stay in Building (no-op)
+                    Want::Building(building)
+                }
+                _ => {
+                    panic!(
+                        "BUG: Want {} in invalid state {:?} for job buffer. Only Idle or Building wants should be scheduled.",
+                        wap.want_id, want
+                    );
+                }
+            };
+
+            self.wants.insert(wap.want_id.clone(), transitioned);
+        }
+
+        // Transition partitions to Building state
+        self.transition_partitions_to_building(&job_run.building_partitions, &event.job_run_id);
+
+        self.job_runs
+            .insert(event.job_run_id.clone(), job_run.clone());
+        println!("Inserted job run: {:?}", job_run);
+        vec![]
     }
 
     fn update_job_run_status(
         &mut self,
         job_run_id: &str,
         status: JobRunStatusCode,
-    ) -> Result<(), DatabuildError> {
+    ) {
-        if let Some(job_run) = self.job_runs.get_mut(job_run_id) {
+        let job_run = self.job_runs.get_mut(job_run_id).expect(&format!(
-            job_run.last_heartbeat_at = Some(current_timestamp());
+            "BUG: Job run ID {} must exist to update status",
-            job_run.status = Some(status.into());
+            job_run_id
-            Ok(())
+        ));
-        } else {
+        job_run.last_heartbeat_at = Some(current_timestamp());
-            Err(format!("Job run ID {} not found", job_run_id).into())
+        job_run.status = Some(status.into());
-        }
     }
 
     fn handle_job_run_heartbeat(
         &mut self,
         event: &JobRunHeartbeatEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
-        self.update_job_run_status(&event.job_run_id, JobRunStatusCode::JobRunRunning)?;
+        self.update_job_run_status(&event.job_run_id, JobRunStatusCode::JobRunRunning);
-        Ok(vec![])
+        vec![]
     }
 
     fn handle_job_run_success(
         &mut self,
         event: &JobRunSuccessEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
         println!("Job run success event: {:?}", event);
-        self.update_job_run_status(&event.job_run_id, JobRunStatusCode::JobRunSucceeded)?;
+        self.update_job_run_status(&event.job_run_id, JobRunStatusCode::JobRunSucceeded);
         let job_run = self.get_job_run(&event.job_run_id).unwrap();
 
         // Clone building_partitions before we use it multiple times
@@ -722,14 +724,14 @@ impl BuildState {
         // UpstreamBuilding → Idle/Building (for downstream wants waiting on newly successful wants)
         self.unblock_downstream_wants(&newly_successful_wants, &event.job_run_id, current_timestamp());
 
-        Ok(vec![])
+        vec![]
     }
 
     fn handle_job_run_failure(
         &mut self,
         event: &JobRunFailureEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
-        self.update_job_run_status(&event.job_run_id, JobRunStatusCode::JobRunFailed)?;
+        self.update_job_run_status(&event.job_run_id, JobRunStatusCode::JobRunFailed);
         let job_run = self.get_job_run(&event.job_run_id).unwrap();
 
         // Clone building_partitions before we use it multiple times
@@ -744,31 +746,31 @@ impl BuildState {
         // UpstreamBuilding → UpstreamFailed (for downstream wants waiting on newly failed wants)
         self.cascade_failures_to_downstream_wants(&newly_failed_wants, current_timestamp());
 
-        Ok(vec![])
+        vec![]
     }
 
     fn handle_job_run_cancel(
         &mut self,
-        event: &JobRunCancelEventV1,
+        _event: &JobRunCancelEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
         todo!("should update already inserted job run, partition status, want status")
     }
 
     pub fn handle_job_run_dep_miss(
         &mut self,
         event: &JobRunMissingDepsEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
-        let job_run_detail = self.get_job_run(&event.job_run_id).ok_or(format!(
+        let job_run_detail = self.get_job_run(&event.job_run_id).expect(&format!(
-            "Unable to find job run with id `{}`",
+            "BUG: Unable to find job run with id `{}`",
             event.job_run_id
-        ))?;
+        ));
         // Infer data/SLA timestamps from upstream want
         let want_timestamps: WantTimestamps = job_run_detail
             .servicing_wants
             .iter()
             .flat_map(|wap| self.get_want(&wap.want_id).map(|w| w.into()))
             .reduce(|a: WantTimestamps, b: WantTimestamps| a.merge(b))
-            .ok_or(format!("No servicing wants found"))?;
+            .expect("BUG: No servicing wants found");
 
         // Transition partitions back to Missing since this job can't build them yet
         self.reset_partitions_to_missing(&job_run_detail.building_partitions);
@@ -796,20 +798,20 @@ impl BuildState {
             &partition_to_want_map,
         );
 
-        Ok(want_events)
+        want_events
     }
 
     fn handle_taint_create(
         &mut self,
-        event: &TaintCreateEventV1,
+        _event: &TaintCreateEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
         todo!("...?")
     }
 
     fn handle_taint_delete(
         &mut self,
-        event: &TaintCancelEventV1,
+        _event: &TaintCancelEventV1,
-    ) -> Result<Vec<Event>, DatabuildError> {
+    ) -> Vec<Event> {
         todo!("...?")
     }
 
@@ -1077,9 +1079,7 @@ mod tests {
                 e.partitions = vec!["mypart".into()];
 
                 let mut state = BuildState::default();
-                state
+                state.handle_event(&e.clone().into());
-                    .handle_event(&e.clone().into())
-                    .expect("want create failed");
                 let want = state.get_want("1234").unwrap();
                 let mut expected: WantDetail = e.into();
                 // Into will set this field as current timestamp
@@ -1094,16 +1094,12 @@ mod tests {
                 e.partitions = vec!["mypart".into()];
 
                 let mut state = BuildState::default();
-                state
+                state.handle_event(&e.clone().into());
-                    .handle_event(&e.clone().into())
-                    .expect("want create failed");
 
                 // Should be able to cancel
                 let mut e = WantCancelEventV1::default();
                 e.want_id = "1234".to_string();
-                state
+                state.handle_event(&e.clone().into());
-                    .handle_event(&e.clone().into())
-                    .expect("want cancel failed");
                 let want = state.get_want("1234").unwrap();
 
                 assert_eq!(