text/template/parse: rename DeferFuncCheck to SkipFuncCheck

The proposal as accepted in #34652 named the bit SkipFuncCheck.
It was renamed to DeferFuncCheck during the code review on a suggestion by Rob,
along with a comment to “defer type checking functions until template is executed,”
but this description is not accurate: the package has never type-checked functions,
only verified their existence. And the effect of the bit in this package is to eliminate
this check entirely, not to defer it to some later time.

I was writing code using this new bit and was very confused about when the
"type checking" was being deferred to and how to stop that entirely,
since in my use case I wanted no checks at all. What I wanted is what the bit does,
it just wasn't named accurately.

Rename back to SkipFuncCheck.

Change-Id: I8e62099c8a904ed04521eb5b86155290f6d5b12f
Reviewed-on: https://go-review.googlesource.com/c/go/+/317269
Trust: Russ Cox <[email protected]>
Trust: Daniel Martí <[email protected]>
Run-TryBot: Russ Cox <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Rob Pike <[email protected]>

api/next.txt

@@ -90,8 +90,8 @@ pkg syscall (windows-amd64), type SysProcAttr struct, AdditionalInheritedHandles
 pkg syscall (windows-amd64), type SysProcAttr struct, ParentProcess Handle
 pkg testing, method (*B) Setenv(string, string)
 pkg testing, method (*T) Setenv(string, string)
-pkg text/template/parse, const DeferFuncCheck = 2
-pkg text/template/parse, const DeferFuncCheck Mode
+pkg text/template/parse, const SkipFuncCheck = 2
+pkg text/template/parse, const SkipFuncCheck Mode
 pkg time, func UnixMicro(int64) Time
 pkg time, func UnixMilli(int64) Time
 pkg time, method (*Time) IsDST() bool

src/text/template/parse/parse.go

@@ -38,8 +38,8 @@ type Tree struct {
 type Mode uint
 
 const (
- ParseComments  Mode = 1 << iota // parse comments and add them to AST
- DeferFuncCheck // defer type checking functions until template is executed
+ ParseComments Mode = 1 << iota // parse comments and add them to AST
+ SkipFuncCheck // do not check that functions are defined
 )
 
 // Copy returns a copy of the Tree. Any parsing state is discarded.
@@ -690,7 +690,7 @@ func (t *Tree) operand() Node {
 func (t *Tree) term() Node {
  switch token := t.nextNonSpace(); token.typ {
  case itemIdentifier:
- checkFunc := t.Mode&DeferFuncCheck == 0
+ checkFunc := t.Mode&SkipFuncCheck == 0
  if checkFunc && !t.hasFunction(token.val) {
  t.errorf("function %q not defined", token.val)
  }

src/text/template/parse/parse_test.go

@@ -379,12 +379,12 @@ func TestParseWithComments(t *testing.T) {
  }
 }
 
-func TestDeferFuncCheck(t *testing.T) {
+func TestSkipFuncCheck(t *testing.T) {
  oldTextFormat := textFormat
  textFormat = "%q"
  defer func() { textFormat = oldTextFormat }()
- tr := New("defer func check")
- tr.Mode = DeferFuncCheck
+ tr := New("skip func check")
+ tr.Mode = SkipFuncCheck
  tmpl, err := tr.Parse("{{fn 1 2}}", "", "", make(map[string]*Tree))
  if err != nil {
  t.Fatalf("unexpected error: %v", err)