Add new func for released version comparisons

internal/pkg/agent/application/upgrade/upgrade.go

@@ -163,6 +163,17 @@ func (av agentVersion) String() string {
 func (u *Upgrader) Upgrade(ctx context.Context, version string, sourceURI string, action *fleetapi.ActionUpgrade, det *details.Details, skipVerifyOverride bool, skipDefaultPgp bool, pgpBytes ...string) (_ reexec.ShutdownCallbackFn, err error) {
 	u.log.Infow("Upgrading agent", "version", version, "source_uri", sourceURI)
 
+	currentVersion := agentVersion{
+		version:  release.Version(),
+		snapshot: release.Snapshot(),
+		hash:     release.Commit(),
+	}
+
+	if isSameReleaseVersion(currentVersion, version) {
+		u.log.Warnf("Upgrade action skipped because agent is already at version %s", currentVersion)
+		return nil, ErrUpgradeSameVersion
+	}
+
 	// Inform the Upgrade Marker Watcher that we've started upgrading. Note that this
 	// is only possible to do in-memory since, today, the  process that's initiating
 	// the upgrade is the same as the Agent process in which the Upgrade Marker Watcher is
@@ -207,12 +218,6 @@ func (u *Upgrader) Upgrade(ctx context.Context, version string, sourceURI string
 		return nil, fmt.Errorf("reading metadata for elastic agent version %s package %q: %w", version, archivePath, err)
 	}
 
-	currentVersion := agentVersion{
-		version:  release.Version(),
-		snapshot: release.Snapshot(),
-		hash:     release.Commit(),
-	}
-
 	same, newVersion := isSameVersion(u.log, currentVersion, metadata, version)
 	if same {
 		u.log.Warnf("Upgrade action skipped because agent is already at version %s", currentVersion)
@@ -628,3 +633,17 @@ func IsInProgress(c client.Client, watcherPIDsFetcher func() ([]int, error)) (bo
 
 	return state.State == cproto.State_UPGRADING, nil
 }
+
+// isSameReleaseVersion will if upgradeVersion and currentVersion are equal using only release numbers.
+// They are not equal if either are a SNAPSHOT, or if the semver numbers (including prerelease and build identifiers) differ.
+func isSameReleaseVersion(current agentVersion, upgradeVersion string) bool {
+	if current.snapshot {
+		return false
+	}
+	target, _ := agtversion.ParseVersion(upgradeVersion)
+	targetVersion, targetSnapshot := target.ExtractSnapshotFromVersionString()
+	if targetSnapshot {
+		return false
+	}
+	return current.version == targetVersion
+}

internal/pkg/agent/application/upgrade/upgrade_test.go

@@ -1000,3 +1000,60 @@ func Test_selectWatcherExecutable(t *testing.T) {
 		})
 	}
 }
+
+func TestIsSameReleaseVersion(t *testing.T) {
+	tests := []struct {
+		name    string
+		current agentVersion
+		target  string
+		expect  bool
+	}{{
+		name: "current version is snapshot",
+		current: agentVersion{
+			version:  "1.2.3",
+			snapshot: true,
+		},
+		target: "1.2.3",
+		expect: false,
+	}, {
+		name: "target version is snapshot",
+		current: agentVersion{
+			version: "1.2.3",
+		},
+		target: "1.2.3-SNAPSHOT",
+		expect: false,
+	}, {
+		name: "target version is different version",
+		current: agentVersion{
+			version: "1.2.3",
+		},
+		target: "1.2.4",
+		expect: false,
+	}, {
+		name: "target version is same with pre-release",
+		current: agentVersion{
+			version: "1.2.3",
+		},
+		target: "1.2.3-custom.info",
+		expect: false,
+	}, {
+		name: "target version is same with build",
+		current: agentVersion{
+			version: "1.2.3",
+		},
+		target: "1.2.3+buildID",
+		expect: false,
+	}, {
+		name: "target version is same",
+		current: agentVersion{
+			version: "1.2.3",
+		},
+		target: "1.2.3",
+		expect: true,
+	}}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			assert.Equal(t, tc.expect, isSameReleaseVersion(tc.current, tc.target))
+		})
+	}
+}