config: warn undefined config item

Signed-off-by: nolouch <nolouch@gmail.com>

conf/config.toml

@@ -67,7 +67,7 @@ leader-schedule-limit = 4
 region-schedule-limit = 1024
 replica-schedule-limit = 1024
 merge-schedule-limit = 8
-tolerant-size-ratio = 0
+# tolerant-size-ratio = 0.0
 
 # customized schedulers, the format is as below
 # if empty, it will use balance-leader, balance-region, hot-region as default
@@ -83,6 +83,7 @@ max-replicas = 3
 # For example, ["zone", "rack"] means that we should place replicas to
 # different zones first, then to different racks if we don't have enough zones.
 location-labels = []
+# strictly-match-label = false
 
 [label-property]
 # Do not assign region leaders to stores that have these tags.

server/config.go

@@ -350,7 +350,7 @@ func (m *configMetaData) CheckUndecoded() error {
 func (c *Config) Adjust(meta *toml.MetaData) error {
 	configMetaData := newConfigMetadata(meta)
 	if err := configMetaData.CheckUndecoded(); err != nil {
-		return err
+		c.WarningMsgs = append(c.WarningMsgs, err.Error())
 	}
 
 	if c.Name == "" {

server/config_test.go

@@ -17,6 +17,7 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"strings"
 	"time"
 
 	"github.com/BurntSushi/toml"
@@ -131,7 +132,8 @@ type = "random-merge"
 	meta, err = toml.Decode(cfgData, &cfg)
 	c.Assert(err, IsNil)
 	err = cfg.Adjust(&meta)
-	c.Assert(err, NotNil)
+	c.Assert(err, IsNil)
+	c.Assert(strings.Contains(cfg.WarningMsgs[0], "Config contains undefined item"), IsTrue)
 
 	// Check misspelled schedulers name
 	cfgData = `