1 files changed, 181 insertions, 0 deletions
diff --git a/internal/app/errors.go b/internal/app/errors.go
new file mode 100644
index 00000000..b9bd6f57
--- /dev/null
+++ b/internal/app/errors.go
@@ -0,0 +1,181 @@
+package app
+
+import (
+	"errors"
+	"log"
+
+	"hakurei.app/internal/hlog"
+)
+
+func PrintRunStateErr(rs *RunState, runErr error) (code int) {
+	code = rs.ExitStatus()
+
+	if runErr != nil {
+		if rs.Time == nil {
+			hlog.PrintBaseError(runErr, "cannot start app:")
+		} else {
+			var e *hlog.BaseError
+			if !hlog.AsBaseError(runErr, &e) {
+				log.Println("wait failed:", runErr)
+			} else {
+				// Wait only returns either *app.ProcessError or *app.StateStoreError wrapped in a *app.BaseError
+				var se *StateStoreError
+				if !errors.As(runErr, &se) {
+					// does not need special handling
+					log.Print(e.Message())
+				} else {
+					// inner error are either unwrapped store errors
+					// or joined errors returned by *appSealTx revert
+					// wrapped in *app.BaseError
+					var ej RevertCompoundError
+					if !errors.As(se.InnerErr, &ej) {
+						// does not require special handling
+						log.Print(e.Message())
+					} else {
+						errs := ej.Unwrap()
+
+						// every error here is wrapped in *app.BaseError
+						for _, ei := range errs {
+							var eb *hlog.BaseError
+							if !errors.As(ei, &eb) {
+								// unreachable
+								log.Println("invalid error type returned by revert:", ei)
+							} else {
+								// print inner *app.BaseError message
+								log.Print(eb.Message())
+							}
+						}
+					}
+				}
+			}
+		}
+
+		if code == 0 {
+			code = 126
+		}
+	}
+
+	if rs.RevertErr != nil {
+		var stateStoreError *StateStoreError
+		if !errors.As(rs.RevertErr, &stateStoreError) || stateStoreError == nil {
+			hlog.PrintBaseError(rs.RevertErr, "generic fault during cleanup:")
+			goto out
+		}
+
+		if stateStoreError.Err != nil {
+			if len(stateStoreError.Err) == 2 {
+				if stateStoreError.Err[0] != nil {
+					if joinedErrs, ok := stateStoreError.Err[0].(interface{ Unwrap() []error }); !ok {
+						hlog.PrintBaseError(stateStoreError.Err[0], "generic fault during revert:")
+					} else {
+						for _, err := range joinedErrs.Unwrap() {
+							if err != nil {
+								hlog.PrintBaseError(err, "fault during revert:")
+							}
+						}
+					}
+				}
+				if stateStoreError.Err[1] != nil {
+					log.Printf("cannot close store: %v", stateStoreError.Err[1])
+				}
+			} else {
+				log.Printf("fault during cleanup: %v",
+					errors.Join(stateStoreError.Err...))
+			}
+		}
+
+		if stateStoreError.OpErr != nil {
+			log.Printf("blind revert due to store fault: %v",
+				stateStoreError.OpErr)
+		}
+
+		if stateStoreError.DoErr != nil {
+			hlog.PrintBaseError(stateStoreError.DoErr, "state store operation unsuccessful:")
+		}
+
+		if stateStoreError.Inner && stateStoreError.InnerErr != nil {
+			hlog.PrintBaseError(stateStoreError.InnerErr, "cannot destroy state entry:")
+		}
+
+	out:
+		if code == 0 {
+			code = 128
+		}
+	}
+	if rs.WaitErr != nil {
+		hlog.Verbosef("wait: %v", rs.WaitErr)
+	}
+	return
+}
+
+// StateStoreError is returned for a failed state save
+type StateStoreError struct {
+	// whether inner function was called
+	Inner bool
+	// returned by the Save/Destroy method of [state.Cursor]
+	InnerErr error
+	// returned by the Do method of [state.Store]
+	DoErr error
+	// stores an arbitrary store operation error
+	OpErr error
+	// stores arbitrary errors
+	Err []error
+}
+
+// save saves arbitrary errors in [StateStoreError] once.
+func (e *StateStoreError) save(errs ...error) {
+	if len(errs) == 0 || e.Err != nil {
+		panic("invalid call to save")
+	}
+	e.Err = errs
+}
+
+func (e *StateStoreError) equiv(a ...any) error {
+	if e.Inner && e.InnerErr == nil && e.DoErr == nil && e.OpErr == nil && errors.Join(e.Err...) == nil {
+		return nil
+	} else {
+		return hlog.WrapErrSuffix(e, a...)
+	}
+}
+
+func (e *StateStoreError) Error() string {
+	if e.Inner && e.InnerErr != nil {
+		return e.InnerErr.Error()
+	}
+	if e.DoErr != nil {
+		return e.DoErr.Error()
+	}
+	if e.OpErr != nil {
+		return e.OpErr.Error()
+	}
+	if err := errors.Join(e.Err...); err != nil {
+		return err.Error()
+	}
+
+	// equiv nullifies e for values where this is reached
+	panic("unreachable")
+}
+
+func (e *StateStoreError) Unwrap() (errs []error) {
+	errs = make([]error, 0, 3)
+	if e.InnerErr != nil {
+		errs = append(errs, e.InnerErr)
+	}
+	if e.DoErr != nil {
+		errs = append(errs, e.DoErr)
+	}
+	if e.OpErr != nil {
+		errs = append(errs, e.OpErr)
+	}
+	if err := errors.Join(e.Err...); err != nil {
+		errs = append(errs, err)
+	}
+	return
+}
+
+// A RevertCompoundError encapsulates errors returned by
+// the Revert method of [system.I].
+type RevertCompoundError interface {
+	Error() string
+	Unwrap() []error
+}