Extract publication recovery observation

internal/publish/reconcile.go

@@ -0,0 +1,138 @@
+package publish
+
+import (
+	"context"
+	"errors"
+
+	"go.maximumdirect.net/releasekit/internal/git"
+)
+
+// Evidence is the identity captured when one publication was attempted.
+type Evidence struct {
+	RepositoryDir   string
+	ModuleDir       string
+	ModulePath      string
+	Version         string
+	Tag             string
+	CandidateCommit string
+	TagObject       string
+	Endpoint        string
+	Remote          string
+	RecordedAt      string
+}
+
+// Observation combines the original evidence with authoritative remote state.
+type Observation struct {
+	Evidence          Evidence
+	State             State
+	ObservedTagObject string
+	ObservedCommit    string
+}
+
+// RecoveryError describes why a later publication observation is unresolved.
+type RecoveryError struct {
+	Kind          string
+	MissingFields []string
+	cause         error
+}
+
+func (e *RecoveryError) Error() string {
+	if e == nil {
+		return ""
+	}
+	message := "publication recovery " + e.Kind
+	if e.cause != nil {
+		return message + ": " + git.DisplayError(e.cause).Error()
+	}
+	return message
+}
+func (e *RecoveryError) Unwrap() error {
+	if e == nil {
+		return nil
+	}
+	return e.cause
+}
+
+func classify(evidence Evidence, remoteTag git.RemoteRef) (Observation, error) {
+	result := Observation{Evidence: evidence, State: Unknown, ObservedTagObject: remoteTag.Object, ObservedCommit: remoteTag.Peeled}
+	missing := []string{}
+	if evidence.Endpoint == "" {
+		missing = append(missing, "endpoint")
+	}
+	if evidence.Tag == "" {
+		missing = append(missing, "tag")
+	}
+	if len(missing) > 0 {
+		return result, &RecoveryError{Kind: "missing_evidence", MissingFields: missing}
+	}
+	if remoteTag.State == git.RefAbsent {
+		result.State = NotPublished
+		return result, nil
+	}
+	if evidence.TagObject == "" {
+		return result, &RecoveryError{Kind: "missing_evidence", MissingFields: []string{"tag_object"}}
+	}
+	if remoteTag.State != git.RefPresent {
+		return result, &RecoveryError{Kind: "inconsistent_observation", cause: git.ErrRemoteStateUnreadable}
+	}
+	if !git.EqualObjectID(remoteTag.Object, evidence.TagObject) {
+		result.State = Conflict
+		return result, nil
+	}
+	if remoteTag.Peeled != "" {
+		if evidence.CandidateCommit == "" {
+			return result, &RecoveryError{Kind: "missing_evidence", MissingFields: []string{"candidate_commit"}}
+		}
+		if !git.EqualObjectID(remoteTag.Peeled, evidence.CandidateCommit) {
+			result.State = Conflict
+			return result, nil
+		}
+	}
+	result.State = Published
+	return result, nil
+}
+
+func observe(ctx context.Context, evidence Evidence) (Observation, error) {
+	if err := ctx.Err(); err != nil {
+		return Observation{Evidence: evidence, State: Unknown}, &RecoveryError{Kind: "canceled", cause: err}
+	}
+	if evidence.Endpoint == "" || evidence.Tag == "" {
+		return classify(evidence, git.RemoteRef{})
+	}
+	if evidence.TagObject != "" && !git.ValidObjectID(evidence.TagObject) {
+		return Observation{Evidence: evidence, State: Unknown}, &RecoveryError{Kind: "invalid_evidence"}
+	}
+	if evidence.CandidateCommit != "" && !git.ValidObjectID(evidence.CandidateCommit) {
+		return Observation{Evidence: evidence, State: Unknown}, &RecoveryError{Kind: "invalid_evidence"}
+	}
+	valid, err := git.ValidateTagRef(ctx, evidence.RepositoryDir, evidence.Tag)
+	if err != nil {
+		return Observation{Evidence: evidence, State: Unknown}, &RecoveryError{Kind: "remote_observation", cause: err}
+	}
+	if !valid {
+		return Observation{Evidence: evidence, State: Unknown}, &RecoveryError{Kind: "invalid_evidence"}
+	}
+	endpoint, err := git.ObserveEndpoint(ctx, evidence.RepositoryDir, evidence.Endpoint, evidence.Remote)
+	if err != nil {
+		if ctx.Err() != nil {
+			return Observation{Evidence: evidence, State: Unknown}, &RecoveryError{Kind: "canceled", cause: ctx.Err()}
+		}
+		kind := "endpoint_changed"
+		if errors.Is(err, git.ErrEndpointChanged) {
+			return Observation{Evidence: evidence, State: Unknown}, &RecoveryError{Kind: kind, cause: err}
+		}
+		if evidence.Remote != "" {
+			kind = "transport_configuration"
+		}
+		return Observation{Evidence: evidence, State: Unknown}, &RecoveryError{Kind: kind, cause: err}
+	}
+	ref, err := endpoint.QueryTag(ctx, evidence.RepositoryDir, evidence.Tag)
+	if err != nil {
+		return Observation{Evidence: evidence, State: Unknown}, &RecoveryError{Kind: "remote_observation", cause: err}
+	}
+	result, err := classify(evidence, ref)
+	if err != nil && ctx.Err() != nil {
+		return result, &RecoveryError{Kind: "canceled", cause: ctx.Err()}
+	}
+	return result, err
+}