transactions: Document exported errors

Exported errors in the transaction code didn't yet have any
documentation, which this commit amends now.

2 files changed, 15 insertions, 4 deletions

diff --git a/internal/praefect/transactions/subtransaction.go b/internal/praefect/transactions/subtransaction.go
index 1c1c782f8..9950ea53a 100644
--- a/internal/praefect/transactions/subtransaction.go
+++ b/internal/praefect/transactions/subtransaction.go
@@ -9,8 +9,11 @@ import (
 )
 
 var (
+	// ErrTransactionVoteFailed indicates the transaction didn't reach quorum.
 	ErrTransactionVoteFailed = errors.New("transaction did not reach quorum")
-	ErrTransactionCanceled   = errors.New("transaction was canceled")
+	// ErrTransactionCanceled indicates the transaction was canceled before
+	// reaching quorum.
+	ErrTransactionCanceled = errors.New("transaction was canceled")
 )
 
 // voteResult represents the outcome of a transaction for a single voter.
diff --git a/internal/praefect/transactions/transaction.go b/internal/praefect/transactions/transaction.go
index 024f7d5bd..cfcca1658 100644
--- a/internal/praefect/transactions/transaction.go
+++ b/internal/praefect/transactions/transaction.go
@@ -7,9 +7,17 @@ import (
 )
 
 var (
-	ErrDuplicateNodes       = errors.New("transactions cannot have duplicate nodes")
-	ErrMissingNodes         = errors.New("transaction requires at least one node")
-	ErrInvalidThreshold     = errors.New("transaction has invalid threshold")
+	// ErrDuplicateNodes indicates a transaction was registered with two
+	// voters having the same name.
+	ErrDuplicateNodes = errors.New("transactions cannot have duplicate nodes")
+	// ErrMissingNodes indicates a transaction was registered with no voters.
+	ErrMissingNodes = errors.New("transaction requires at least one node")
+	// ErrInvalidThreshold indicates a transaction was registered with an
+	// invalid threshold that may either allow for multiple different
+	// quorums or none at all.
+	ErrInvalidThreshold = errors.New("transaction has invalid threshold")
+	// ErrSubtransactionFailed indicates a vote was cast on a
+	// subtransaction which failed already.
 	ErrSubtransactionFailed = errors.New("subtransaction has failed")
 )