chore(backups/DeltaReplication): unify base VM detection

Might help avoiding the *unable to find base VM* error.

@xen-orchestra/backups/ImportVmBackup.js

@@ -44,7 +44,6 @@ exports.ImportVmBackup = class ImportVmBackup {
           ? await xapi.VM_import(backup, srRef)
           : await importDeltaVm(backup, await xapi.getRecord('SR', srRef), {
               ...this._importDeltaVmSettings,
-              detectBase: false,
             })
 
         await Promise.all([

@xen-orchestra/backups/_deltaVm.js

@@ -143,7 +143,14 @@ exports.importDeltaVm = defer(async function importDeltaVm(
   $defer,
   deltaVm,
   sr,
-  { cancelToken = CancelToken.none, detectBase = true, mapVdisSrs = {}, newMacAddresses = false } = {}
+  {
+    // can be set to a specific VM
+    baseVm = false,
+
+    cancelToken = CancelToken.none,
+    mapVdisSrs = {},
+    newMacAddresses = false,
+  } = {}
 ) {
   const { version } = deltaVm
   if (compareVersions(version, '1.0.0') < 0) {
@@ -153,16 +160,8 @@ exports.importDeltaVm = defer(async function importDeltaVm(
   const vmRecord = deltaVm.vm
   const xapi = sr.$xapi
 
-  let baseVm
-  if (detectBase) {
-    const remoteBaseVmUuid = vmRecord.other_config[TAG_BASE_DELTA]
-    if (remoteBaseVmUuid) {
-      baseVm = find(xapi.objects.all, obj => (obj = obj.other_config) && obj[TAG_COPY_SRC] === remoteBaseVmUuid)
-
-      if (!baseVm) {
-        throw new Error(`could not find the base VM (copy of ${remoteBaseVmUuid})`)
-      }
-    }
+  if (!(baseVm === false || TAG_BASE_DELTA in vmRecord.other_config)) {
+    baseVm = undefined
   }
 
   const baseVdis = {}
@@ -230,7 +229,7 @@ exports.importDeltaVm = defer(async function importDeltaVm(
     const vdi = vdiRecords[vdiRef]
     let newVdi
 
-    const remoteBaseVdiUuid = detectBase && vdi.other_config[TAG_BASE_DELTA]
+    const remoteBaseVdiUuid = baseVm && vdi.other_config[TAG_BASE_DELTA]
     if (remoteBaseVdiUuid) {
       const baseVdi = find(baseVdis, vdi => vdi.other_config[TAG_COPY_SRC] === remoteBaseVdiUuid)
       if (!baseVdi) {

@xen-orchestra/backups/writers/DeltaReplicationWriter.js

@@ -12,6 +12,8 @@ const { MixinReplicationWriter } = require('./_MixinReplicationWriter.js')
 const { listReplicatedVms } = require('./_listReplicatedVms.js')
 
 exports.DeltaReplicationWriter = class DeltaReplicationWriter extends MixinReplicationWriter(AbstractDeltaWriter) {
+  #baseVm
+
   async checkBaseVdis(baseUuidToSrcVdi, baseVm) {
     const sr = this._sr
     const replicatedVm = listReplicatedVms(sr.$xapi, this._backup.job.id, sr.uuid, this._backup.vm.uuid).find(
@@ -21,6 +23,8 @@ exports.DeltaReplicationWriter = class DeltaReplicationWriter extends MixinRepli
       return baseUuidToSrcVdi.clear()
     }
 
+    this.#baseVm = replicatedVm
+
     const xapi = replicatedVm.$xapi
     const replicatedVdis = new Set(
       await asyncMap(await replicatedVm.$getDisks(), async vdiRef => {
@@ -88,6 +92,7 @@ exports.DeltaReplicationWriter = class DeltaReplicationWriter extends MixinRepli
       targetVmRef = await importDeltaVm(
         {
           __proto__: deltaExport,
+          baseVm: this.#baseVm,
           vm: {
             ...deltaExport.vm,
             tags: [...deltaExport.vm.tags, 'Continuous Replication'],