0th version now shows a diff if a specific diff target is requested

command/agent/job_endpoint.go

@@ -771,9 +771,6 @@ func (s *HTTPServer) jobVersions(resp http.ResponseWriter, req *http.Request, jo
 	diffTagName := req.URL.Query().Get("diff_tag")
 	diffVersion := req.URL.Query().Get("diff_version")
 
-	// log out
-	s.logger.Debug("++==jobVersions", "diffs", diffsStr, "diff_tag", diffTagName, "diff_version", diffVersion)
-
 	var diffsBool bool
 	if diffsStr != "" {
 		var err error

command/job_history.go

@@ -161,7 +161,6 @@ func (c *JobHistoryCommand) Run(args []string) int {
 
 	// Prefix lookup matched a single job
 	versions, diffs, _, err := client.Jobs().Versions(jobID, diff, diffTag, diffVersion, q)
-	// TODO: something about diffs isn't ever giving me something for the 0th version. Maybe in job_endpoint.go instead?
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Error retrieving job versions: %s", err))
 		return 1
@@ -247,15 +246,14 @@ func parseVersion(input string) (uint64, bool, error) {
 func (c *JobHistoryCommand) formatJobVersions(versions []*api.Job, diffs []*api.JobDiff, full bool) error {
 	vLen := len(versions)
 	dLen := len(diffs)
-	if dLen != 0 && vLen != dLen+1 {
-		return fmt.Errorf("Number of job versions %d doesn't match number of diffs %d", vLen, dLen)
-	}
 
 	for i, version := range versions {
 		var diff *api.JobDiff
 		var nextVersion uint64
-		if i+1 <= dLen {
+		if dLen > i && diffs[i] != nil {
 			diff = diffs[i]
+		}
+		if i+1 < vLen { // if the current version is not the last version
 			nextVersion = *versions[i+1].Version
 		}
 

nomad/job_endpoint.go

@@ -1268,8 +1268,6 @@ func (j *Job) GetJob(args *structs.JobSpecificRequest,
 // GetJobVersions is used to retrieve all tracked versions of a job.
 func (j *Job) GetJobVersions(args *structs.JobVersionsRequest,
 	reply *structs.JobVersionsResponse) error {
-	// log
-	j.logger.Debug("GetJobVersions", "args.DiffVersion", args.DiffVersion, "args.DiffTagName", args.DiffTagName)
 	authErr := j.srv.Authenticate(j.ctx, args)
 	if done, err := j.srv.forward("Job.GetJobVersions", args, args, reply); done {
 		return err
@@ -1310,17 +1308,10 @@ func (j *Job) GetJobVersions(args *structs.JobVersionsRequest,
 					compareStatic = true
 					tagFound := false
 					for _, version := range out {
-						j.logger.Debug("=== checking for tag version match: ", args.DiffTagName, args.DiffTagName)
-						if version.TaggedVersion != nil {
-							j.logger.Debug("=== checking for tag version match check: ", version.TaggedVersion.Name)
-						}
 						if version.TaggedVersion != nil && version.TaggedVersion.Name == args.DiffTagName {
-							j.logger.Debug("=== VERSION TAG MATCH FOUND", "version.Version", version.Version, "Version.Tag.Name", version.TaggedVersion.Name)
 							tagFound = true
 							compareVersionNumber = version.Version
 							break
-						} else {
-							j.logger.Debug("=== Version not a match", version.Version)
 						}
 					}
 					if !tagFound {
@@ -1334,8 +1325,6 @@ func (j *Job) GetJobVersions(args *structs.JobVersionsRequest,
 					}
 				}
 
-				j.logger.Debug("===== GetJobVersions and compareVersionNumber is", "compareVersionNumber", compareVersionNumber, "compareStatic", compareStatic, "compareVersionTag", args.DiffTagName)
-
 				// Note: a previous assumption here was that the 0th job was the latest, and that we don't modify "old" versions.
 				// Adding version tags breaks this assumption (you can tag an old version, which should unblock /versions queries) so we now look for the highest ModifyIndex.
 				var maxModifyIndex uint64
@@ -1358,11 +1347,16 @@ func (j *Job) GetJobVersions(args *structs.JobVersionsRequest,
 
 				// Compute the diffs
 				if args.Diffs {
-					for i := 0; i < len(out)-1; i++ {
+					for i := 0; i < len(out); i++ {
+						// For each of your job's versions, counting from highest version to lowest
+						// it should either be compared to the NEXT version in out[], or to the pre-specified version from compareStatic.
 						if !compareStatic {
-							compareVersion = out[i+1]
+							if i+1 < len(out) && out[i+1] != nil {
+								compareVersion = out[i+1]
+							} else {
+								break
+							}
 						}
-						j.logger.Debug("diffing job versions", "version", out[i].Version, "i", i, "compareStatic", compareStatic, "compare-version", compareVersion.Version)
 
 						old, new := compareVersion, out[i]
 						d, err := old.Diff(new, true)
@@ -1878,8 +1872,6 @@ func (j *Job) Plan(args *structs.JobPlanRequest, reply *structs.JobPlanResponse)
 	// var existingJob interface{}
 	var existingJob *structs.Job
 
-	j.logger.Debug("===== Plan args for specific diffs", "diffVersion", args.DiffVersion, "diffTagName", args.DiffTagName)
-
 	if args.DiffVersion != "" {
 		// Convert from string to uint64
 		diffVersion, err := strconv.ParseUint(args.DiffVersion, 10, 64)

nomad/state/state_store.go

@@ -2281,7 +2281,7 @@ func (s *StateStore) jobsByIDPrefixAllNamespaces(ws memdb.WatchSet, prefix strin
 	return wrap, nil
 }
 
-// JobVersionsByID returns all the tracked versions of a job.
+// JobVersionsByID returns all the tracked versions of a job, sorted in from highest version to lowest.
 func (s *StateStore) JobVersionsByID(ws memdb.WatchSet, namespace, id string) ([]*structs.Job, error) {
 	txn := s.db.ReadTxn()