Simplify error returns (gosimple)

This fixes:
pkg/api/avatar/avatar.go:261:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/log/file.go:102:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/metrics/graphitebridge/graphite.go:298:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/provisioning/provisioning.go:23:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/alert_notification.go:27:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/alert_notification.go:27:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/annotation.go:105:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/annotation.go:105:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/dashboard.go:351:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/dashboard.go:435:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/dashboard_acl.go:38:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/dashboard_acl.go:38:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/stats.go:22:2: 'if err != nil { return err }; return err' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/team.go:213:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:256:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:256:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:274:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:274:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:482:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:482:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)

pkg/api/avatar/avatar.go

@@ -258,9 +258,6 @@ func (this *thunderTask) fetch() error {
 	this.Avatar.data = &bytes.Buffer{}
 	writer := bufio.NewWriter(this.Avatar.data)
 
-	if _, err = io.Copy(writer, resp.Body); err != nil {
-		return err
-	}
-
-	return nil
+	_, err = io.Copy(writer, resp.Body)
+	return err
 }

pkg/log/file.go

@@ -99,10 +99,7 @@ func (w *FileLogWriter) StartLogger() error {
 		return err
 	}
 	w.mw.SetFd(fd)
-	if err = w.initFd(); err != nil {
-		return err
-	}
-	return nil
+	return w.initFd()
 }
 
 func (w *FileLogWriter) docheck(size int) {

pkg/metrics/graphitebridge/graphite.go

@@ -295,11 +295,7 @@ func writeMetric(buf *bufio.Writer, m model.Metric, mf *dto.MetricFamily) error
 		}
 	}
 
-	if err = addExtentionConventionForRollups(buf, mf, m); err != nil {
-		return err
-	}
-
-	return nil
+	return addExtentionConventionForRollups(buf, mf, m)
 }
 
 func addExtentionConventionForRollups(buf *bufio.Writer, mf *dto.MetricFamily, m model.Metric) error {

pkg/services/provisioning/provisioning.go

@@ -20,11 +20,7 @@ func Init(ctx context.Context, homePath string, cfg *ini.File) error {
 
 	dashboardPath := path.Join(provisioningPath, "dashboards")
 	_, err := dashboards.Provision(ctx, dashboardPath)
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return err
 }
 
 func makeAbsolute(path string, root string) string {

pkg/services/sqlstore/alert_notification.go

@@ -23,12 +23,7 @@ func DeleteAlertNotification(cmd *m.DeleteAlertNotificationCommand) error {
 	return inTransaction(func(sess *DBSession) error {
 		sql := "DELETE FROM alert_notification WHERE alert_notification.org_id = ? AND alert_notification.id = ?"
 		_, err := sess.Exec(sql, cmd.OrgId, cmd.Id)
-
-		if err != nil {
-			return err
-		}
-
-		return nil
+		return err
 	})
 }
 

pkg/services/sqlstore/annotation.go

@@ -102,11 +102,8 @@ func (r *SqlAnnotationRepo) Update(item *annotations.Item) error {
 
 		existing.Tags = item.Tags
 
-		if _, err := sess.Table("annotation").Id(existing.Id).Cols("epoch", "text", "region_id", "tags").Update(existing); err != nil {
-			return err
-		}
-
-		return nil
+		_, err = sess.Table("annotation").Id(existing.Id).Cols("epoch", "text", "region_id", "tags").Update(existing)
+		return err
 	})
 }
 

pkg/services/sqlstore/dashboard.go

@@ -347,12 +347,7 @@ func GetDashboards(query *m.GetDashboardsQuery) error {
 
 	err := x.In("id", query.DashboardIds).Find(&dashboards)
 	query.Result = dashboards
-
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return err
 }
 
 // GetDashboardPermissionsForUser returns the maximum permission the specified user has for a dashboard(s)
@@ -431,12 +426,7 @@ func GetDashboardsByPluginId(query *m.GetDashboardsByPluginIdQuery) error {
 
 	err := x.Where(whereExpr, query.OrgId, query.PluginId).Find(&dashboards)
 	query.Result = dashboards
-
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return err
 }
 
 type DashboardSlugDTO struct {

pkg/services/sqlstore/dashboard_acl.go

@@ -35,10 +35,8 @@ func UpdateDashboardAcl(cmd *m.UpdateDashboardAclCommand) error {
 
 		// Update dashboard HasAcl flag
 		dashboard := m.Dashboard{HasAcl: true}
-		if _, err := sess.Cols("has_acl").Where("id=?", cmd.DashboardId).Update(&dashboard); err != nil {
-			return err
-		}
-		return nil
+		_, err = sess.Cols("has_acl").Where("id=?", cmd.DashboardId).Update(&dashboard)
+		return err
 	})
 }
 

pkg/services/sqlstore/stats.go

@@ -19,10 +19,6 @@ func GetDataSourceStats(query *m.GetDataSourceStatsQuery) error {
 	var rawSql = `SELECT COUNT(*) as count, type FROM data_source GROUP BY type`
 	query.Result = make([]*m.DataSourceStats, 0)
 	err := x.SQL(rawSql).Find(&query.Result)
-	if err != nil {
-		return err
-	}
-
 	return err
 }
 

pkg/services/sqlstore/team.go

@@ -210,11 +210,7 @@ func GetTeamsByUser(query *m.GetTeamsByUserQuery) error {
 	sess.Where("team.org_id=? and team_member.user_id=?", query.OrgId, query.UserId)
 
 	err := sess.Find(&query.Result)
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return err
 }
 
 // AddTeamMember adds a user to a team

pkg/services/sqlstore/user.go

@@ -253,11 +253,8 @@ func ChangeUserPassword(cmd *m.ChangeUserPasswordCommand) error {
 			Updated:  time.Now(),
 		}
 
-		if _, err := sess.Id(cmd.UserId).Update(&user); err != nil {
-			return err
-		}
-
-		return nil
+		_, err := sess.Id(cmd.UserId).Update(&user)
+		return err
 	})
 }
 
@@ -271,11 +268,8 @@ func UpdateUserLastSeenAt(cmd *m.UpdateUserLastSeenAtCommand) error {
 			LastSeenAt: time.Now(),
 		}
 
-		if _, err := sess.Id(cmd.UserId).Update(&user); err != nil {
-			return err
-		}
-
-		return nil
+		_, err := sess.Id(cmd.UserId).Update(&user)
+		return err
 	})
 }
 
@@ -479,10 +473,7 @@ func SetUserHelpFlag(cmd *m.SetUserHelpFlagCommand) error {
 			Updated:    time.Now(),
 		}
 
-		if _, err := sess.Id(cmd.UserId).Cols("help_flags1").Update(&user); err != nil {
-			return err
-		}
-
-		return nil
+		_, err := sess.Id(cmd.UserId).Cols("help_flags1").Update(&user)
+		return err
 	})
 }

pkg/tsdb/cloudwatch/metric_find_query.go

@@ -566,11 +566,7 @@ func getAllMetrics(cwData *DatasourceInfo) (cloudwatch.ListMetricsOutput, error)
 			}
 			return !lastPage
 		})
-	if err != nil {
-		return resp, err
-	}
-
-	return resp, nil
+	return resp, err
 }
 
 var metricsCacheLock sync.Mutex