perf: all: remove unnecessary allocations from strings.Builder.WriteString(fmt.Sprintf(...)) (#13230)

This change removes a code pattern that I noticed while on a late night
audit of cosmovisor in which
strings.Builder.WriteString(fmt.Sprintf(...))
calls were being made, yet that's counterproductive to using fmt.Fprintf
which will check whether the writer implements .WriteString and then
avoids the need to firstly build a string using fmt.Sprintf.

The performance wins from this change transcend all dimensions as
exhibited below:

```shell
$ benchstat before.txt after.txt
name            old time/op    new time/op    delta
DetailString-8    5.48µs ±23%    4.40µs ±11%  -19.79%  (p=0.000 n=20+17)

name            old alloc/op   new alloc/op   delta
DetailString-8    2.63kB ± 0%    2.11kB ± 0%  -19.76%  (p=0.000 n=20+20)

name            old allocs/op  new allocs/op  delta
DetailString-8      63.0 ± 0%      50.0 ± 0%  -20.63%  (p=0.000 n=20+20)
```

Fixes #13229

client/rpc/validators.go

@@ -84,19 +84,17 @@ type ResultValidatorsOutput struct {
 func (rvo ResultValidatorsOutput) String() string {
 	var b strings.Builder
 
-	b.WriteString(fmt.Sprintf("block height: %d\n", rvo.BlockHeight))
-	b.WriteString(fmt.Sprintf("total count: %d\n", rvo.Total))
+	fmt.Fprintf(&b, "block height: %d\n", rvo.BlockHeight)
+	fmt.Fprintf(&b, "total count: %d\n", rvo.Total)
 
 	for _, val := range rvo.Validators {
-		b.WriteString(
-			fmt.Sprintf(`
+		fmt.Fprintf(&b, `
   Address:          %s
   Pubkey:           %s
   ProposerPriority: %d
   VotingPower:      %d
 		`,
-				val.Address, val.PubKey, val.ProposerPriority, val.VotingPower,
-			),
+			val.Address, val.PubKey, val.ProposerPriority, val.VotingPower,
 		)
 	}
 

cosmovisor/args.go

@@ -379,7 +379,7 @@ func (cfg Config) DetailString() string {
 	var sb strings.Builder
 	sb.WriteString("Configurable Values:\n")
 	for _, kv := range configEntries {
-		sb.WriteString(fmt.Sprintf("  %s: %s\n", kv.name, kv.value))
+		fmt.Fprintf(&sb, "  %s: %s\n", kv.name, kv.value)
 	}
 	sb.WriteString("Derived Values:\n")
 	dnl := 0
@@ -390,7 +390,7 @@ func (cfg Config) DetailString() string {
 	}
 	dFmt := fmt.Sprintf("  %%%ds: %%s\n", dnl)
 	for _, kv := range derivedEntries {
-		sb.WriteString(fmt.Sprintf(dFmt, kv.name, kv.value))
+		fmt.Fprintf(&sb, dFmt, kv.name, kv.value)
 	}
 	return sb.String()
 }

cosmovisor/args_test.go

@@ -689,3 +689,29 @@ func (s *argsTestSuite) TestLogConfigOrError() {
 		})
 	}
 }
+
+var sink interface{}
+
+func BenchmarkDetailString(b *testing.B) {
+	cfg := &Config{
+		Home: "/foo", Name: "myd",
+		AllowDownloadBinaries: true,
+		UnsafeSkipBackup:      true,
+		PollInterval:          450 * time.Second,
+		PreupgradeMaxRetries:  1e7,
+	}
+	
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		sink = cfg.DetailString()
+	}
+
+	if sink == nil {
+		b.Fatal("Benchmark did not run")
+	}
+
+	// Otherwise reset the sink.
+	sink = (interface{})(nil)
+}

cosmovisor/errors/multi.go

@@ -55,12 +55,12 @@ func (e MultiError) Len() int {
 // Error implements the error interface for a MultiError.
 func (e *MultiError) Error() string {
 	var sb strings.Builder
-	sb.WriteString(fmt.Sprintf("%d errors: ", len(e.errs)))
+	fmt.Fprintf(&sb, "%d errors: ", len(e.errs))
 	for i, err := range e.errs {
 		if i != 0 {
 			sb.WriteString(", ")
 		}
-		sb.WriteString(fmt.Sprintf("%d: %v", i+1, err))
+		fmt.Fprintf(&sb, "%d: %v", i+1, err)
 	}
 	return sb.String()
 }

server/util_test.go

@@ -107,7 +107,7 @@ func TestInterceptConfigsPreRunHandlerReadsConfigToml(t *testing.T) {
 		t.Fatalf("creating config.toml file failed: %v", err)
 	}
 
-	_, err = writer.WriteString(fmt.Sprintf("db_backend = '%s'\n", testDbBackend))
+	_, err = fmt.Fprintf(writer, "db_backend = '%s'\n", testDbBackend)
 	if err != nil {
 		t.Fatalf("Failed writing string to config.toml: %v", err)
 	}
@@ -148,7 +148,7 @@ func TestInterceptConfigsPreRunHandlerReadsAppToml(t *testing.T) {
 		t.Fatalf("creating app.toml file failed: %v", err)
 	}
 
-	_, err = writer.WriteString(fmt.Sprintf("halt-time = %d\n", testHaltTime))
+	_, err = fmt.Fprintf(writer, "halt-time = %d\n", testHaltTime)
 	if err != nil {
 		t.Fatalf("Failed writing string to app.toml: %v", err)
 	}
@@ -312,7 +312,7 @@ func (v precedenceCommon) setAll(t *testing.T, setFlag *string, setEnvVar *strin
 			t.Fatalf("creating config.toml file failed: %v", err)
 		}
 
-		_, err = writer.WriteString(fmt.Sprintf("[rpc]\nladdr = \"%s\"\n", *setConfigFile))
+		_, err = fmt.Fprintf(writer, "[rpc]\nladdr = \"%s\"\n", *setConfigFile)
 		if err != nil {
 			t.Fatalf("Failed writing string to config.toml: %v", err)
 		}

types/events.go

@@ -244,10 +244,10 @@ func (se StringEvents) String() string {
 	var sb strings.Builder
 
 	for _, e := range se {
-		sb.WriteString(fmt.Sprintf("\t\t- %s\n", e.Type))
+		fmt.Fprintf(&sb, "\t\t- %s\n", e.Type)
 
 		for _, attr := range e.Attributes {
-			sb.WriteString(fmt.Sprintf("\t\t\t- %s\n", attr.String()))
+			fmt.Fprintf(&sb, "\t\t\t- %s\n", attr)
 		}
 	}
 

x/distribution/types/proposal.go

@@ -8,11 +8,11 @@ import (
 // String implements the Stringer interface.
 func (csp CommunityPoolSpendProposal) String() string {
 	var b strings.Builder
-	b.WriteString(fmt.Sprintf(`Community Pool Spend Proposal:
+	fmt.Fprintf(&b, `Community Pool Spend Proposal:
   Title:       %s
   Description: %s
   Recipient:   %s
   Amount:      %s
-`, csp.Title, csp.Description, csp.Recipient, csp.Amount))
+`, csp.Title, csp.Description, csp.Recipient, csp.Amount)
 	return b.String()
 }

x/params/types/proposal/proposal.go

@@ -51,18 +51,18 @@ func (pcp *ParameterChangeProposal) ValidateBasic() error {
 func (pcp ParameterChangeProposal) String() string {
 	var b strings.Builder
 
-	b.WriteString(fmt.Sprintf(`Parameter Change Proposal:
+	fmt.Fprintf(&b, `Parameter Change Proposal:
   Title:       %s
   Description: %s
   Changes:
-`, pcp.Title, pcp.Description))
+`, pcp.Title, pcp.Description)
 
 	for _, pc := range pcp.Changes {
-		b.WriteString(fmt.Sprintf(`    Param Change:
+		fmt.Fprintf(&b, `    Param Change:
       Subspace: %s
       Key:      %s
       Value:    %X
-`, pc.Subspace, pc.Key, pc.Value))
+`, pc.Subspace, pc.Key, pc.Value)
 	}
 
 	return b.String()