tpl/internal: Sync Go template src to Go 1.20

Updates #10691

8 files changed, 175 insertions, 11 deletions

diff --git a/markup/goldmark/codeblocks/integration_test.go b/markup/goldmark/codeblocks/integration_test.go
index d0206957a..29ff0dc7d 100644
--- a/markup/goldmark/codeblocks/integration_test.go
+++ b/markup/goldmark/codeblocks/integration_test.go
@@ -369,6 +369,7 @@ Common
 	}{
 		{"issue-9819", "asdf\n: {#myid}"},
 	} {
+		test := test
 		t.Run(test.name, func(t *testing.T) {
 			t.Parallel()
 			b := hugolib.NewIntegrationTestBuilder(
diff --git a/scripts/fork_go_templates/main.go b/scripts/fork_go_templates/main.go
index 2f8516e8d..c22ecd92c 100644
--- a/scripts/fork_go_templates/main.go
+++ b/scripts/fork_go_templates/main.go
@@ -17,7 +17,7 @@ import (
 )
 
 func main() {
-	// The current is built with be7068fb0804f661515c678bee9224b90b32869a text/template: correct assignment, not declaration, in range
+	// The current is built with de4748c47c67392a57f250714509f590f68ad395 HEAD, tag: go1.20.
 	fmt.Println("Forking ...")
 	defer fmt.Println("Done ...")
 
diff --git a/tpl/internal/go_templates/htmltemplate/content.go b/tpl/internal/go_templates/htmltemplate/content.go
index 65cc3086c..898084876 100644
--- a/tpl/internal/go_templates/htmltemplate/content.go
+++ b/tpl/internal/go_templates/htmltemplate/content.go
@@ -51,7 +51,7 @@ var (
 
 // indirectToStringerOrError returns the value, after dereferencing as many times
 // as necessary to reach the base type (or nil) or an implementation of fmt.Stringer
-// or error,
+// or error.
 func indirectToStringerOrError(a any) any {
 	if a == nil {
 		return nil
diff --git a/tpl/internal/go_templates/testenv/exec.go b/tpl/internal/go_templates/testenv/exec.go
index cd06c4f7e..ca4023647 100644
--- a/tpl/internal/go_templates/testenv/exec.go
+++ b/tpl/internal/go_templates/testenv/exec.go
@@ -5,12 +5,15 @@
 package testenv
 
 import (
+	"context"
 	"os"
 	"os/exec"
 	"runtime"
+	"strconv"
 	"strings"
 	"sync"
 	"testing"
+	"time"
 )
 
 // HasExec reports whether the current system can start new processes
@@ -71,3 +74,102 @@ func CleanCmdEnv(cmd *exec.Cmd) *exec.Cmd {
 	}
 	return cmd
 }
+
+// CommandContext is like exec.CommandContext, but:
+//   - skips t if the platform does not support os/exec,
+//   - sends SIGQUIT (if supported by the platform) instead of SIGKILL
+//     in its Cancel function
+//   - if the test has a deadline, adds a Context timeout and WaitDelay
+//     for an arbitrary grace period before the test's deadline expires,
+//   - fails the test if the command does not complete before the test's deadline, and
+//   - sets a Cleanup function that verifies that the test did not leak a subprocess.
+func CommandContext(t testing.TB, ctx context.Context, name string, args ...string) *exec.Cmd {
+	t.Helper()
+	MustHaveExec(t)
+
+	var (
+		cancelCtx   context.CancelFunc
+		gracePeriod time.Duration // unlimited unless the test has a deadline (to allow for interactive debugging)
+	)
+
+	if t, ok := t.(interface {
+		testing.TB
+		Deadline() (time.Time, bool)
+	}); ok {
+		if td, ok := t.Deadline(); ok {
+			// Start with a minimum grace period, just long enough to consume the
+			// output of a reasonable program after it terminates.
+			gracePeriod = 100 * time.Millisecond
+			if s := os.Getenv("GO_TEST_TIMEOUT_SCALE"); s != "" {
+				scale, err := strconv.Atoi(s)
+				if err != nil {
+					t.Fatalf("invalid GO_TEST_TIMEOUT_SCALE: %v", err)
+				}
+				gracePeriod *= time.Duration(scale)
+			}
+
+			// If time allows, increase the termination grace period to 5% of the
+			// test's remaining time.
+			testTimeout := time.Until(td)
+			if gp := testTimeout / 20; gp > gracePeriod {
+				gracePeriod = gp
+			}
+
+			// When we run commands that execute subprocesses, we want to reserve two
+			// grace periods to clean up: one for the delay between the first
+			// termination signal being sent (via the Cancel callback when the Context
+			// expires) and the process being forcibly terminated (via the WaitDelay
+			// field), and a second one for the delay becween the process being
+			// terminated and and the test logging its output for debugging.
+			//
+			// (We want to ensure that the test process itself has enough time to
+			// log the output before it is also terminated.)
+			cmdTimeout := testTimeout - 2*gracePeriod
+
+			if cd, ok := ctx.Deadline(); !ok || time.Until(cd) > cmdTimeout {
+				// Either ctx doesn't have a deadline, or its deadline would expire
+				// after (or too close before) the test has already timed out.
+				// Add a shorter timeout so that the test will produce useful output.
+				ctx, cancelCtx = context.WithTimeout(ctx, cmdTimeout)
+			}
+		}
+	}
+
+	cmd := exec.CommandContext(ctx, name, args...)
+	/*cmd.Cancel = func() error {
+		if cancelCtx != nil && ctx.Err() == context.DeadlineExceeded {
+			// The command timed out due to running too close to the test's deadline.
+			// There is no way the test did that intentionally — it's too close to the
+			// wire! — so mark it as a test failure. That way, if the test expects the
+			// command to fail for some other reason, it doesn't have to distinguish
+			// between that reason and a timeout.
+			t.Errorf("test timed out while running command: %v", cmd)
+		} else {
+			// The command is being terminated due to ctx being canceled, but
+			// apparently not due to an explicit test deadline that we added.
+			// Log that information in case it is useful for diagnosing a failure,
+			// but don't actually fail the test because of it.
+			t.Logf("%v: terminating command: %v", ctx.Err(), cmd)
+		}
+		return cmd.Process.Signal(Sigquit)
+	}
+	cmd.WaitDelay = gracePeriod*/
+
+	t.Cleanup(func() {
+		if cancelCtx != nil {
+			cancelCtx()
+		}
+		if cmd.Process != nil && cmd.ProcessState == nil {
+			t.Errorf("command was started, but test did not wait for it to complete: %v", cmd)
+		}
+	})
+
+	return cmd
+}
+
+// Command is like exec.Command, but applies the same changes as
+// testenv.CommandContext (with a default Context).
+func Command(t testing.TB, name string, args ...string) *exec.Cmd {
+	t.Helper()
+	return CommandContext(t, context.Background(), name, args...)
+}
diff --git a/tpl/internal/go_templates/testenv/testenv.go b/tpl/internal/go_templates/testenv/testenv.go
index 4e38f5f04..6bfa54a97 100644
--- a/tpl/internal/go_templates/testenv/testenv.go
+++ b/tpl/internal/go_templates/testenv/testenv.go
@@ -14,9 +14,6 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-
-	"github.com/gohugoio/hugo/tpl/internal/go_templates/cfg"
-
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -25,6 +22,8 @@ import (
 	"strings"
 	"sync"
 	"testing"
+
+	"github.com/gohugoio/hugo/tpl/internal/go_templates/cfg"
 )
 
 // Builder reports the name of the builder running this test
@@ -256,6 +255,21 @@ func MustHaveCGO(t testing.TB) {
 	}
 }
 
+// CanInternalLink reports whether the current system can link programs with
+// internal linking.
+func CanInternalLink() bool {
+	return false
+}
+
+// MustInternalLink checks that the current system can link programs with internal
+// linking.
+// If not, MustInternalLink calls t.Skip with an explanation.
+func MustInternalLink(t testing.TB) {
+	if !CanInternalLink() {
+		t.Skipf("skipping test: internal linking on %s/%s is not supported", runtime.GOOS, runtime.GOARCH)
+	}
+}
+
 // HasSymlink reports whether the current system can use os.Symlink.
 func HasSymlink() bool {
 	ok, _ := hasSymlink()
@@ -330,3 +344,20 @@ func SkipIfOptimizationOff(t testing.TB) {
 		t.Skip("skipping test with optimization disabled")
 	}
 }
+
+// WriteImportcfg writes an importcfg file used by the compiler or linker to
+// dstPath containing entries for the packages in std and cmd in addition
+// to the package to package file mappings in additionalPackageFiles.
+func WriteImportcfg(t testing.TB, dstPath string, additionalPackageFiles map[string]string) {
+	/*importcfg, err := goroot.Importcfg()
+	for k, v := range additionalPackageFiles {
+		importcfg += fmt.Sprintf("\npackagefile %s=%s", k, v)
+	}
+	if err != nil {
+		t.Fatalf("preparing the importcfg failed: %s", err)
+	}
+	err = os.WriteFile(dstPath, []byte(importcfg), 0655)
+	if err != nil {
+		t.Fatalf("writing the importcfg failed: %s", err)
+	}*/
+}
diff --git a/tpl/internal/go_templates/texttemplate/parse/lex.go b/tpl/internal/go_templates/texttemplate/parse/lex.go
index 3e60a1ece..70fc86b63 100644
--- a/tpl/internal/go_templates/texttemplate/parse/lex.go
+++ b/tpl/internal/go_templates/texttemplate/parse/lex.go
@@ -520,7 +520,7 @@ func lexVariable(l *lexer) stateFn {
 	return lexFieldOrVariable(l, itemVariable)
 }
 
-// lexVariable scans a field or variable: [.$]Alphanumeric.
+// lexFieldOrVariable scans a field or variable: [.$]Alphanumeric.
 // The . or $ has been scanned.
 func lexFieldOrVariable(l *lexer, typ itemType) stateFn {
 	if l.atTerminator() { // Nothing interesting follows -> "." or "$".
diff --git a/tpl/internal/go_templates/texttemplate/parse/parse.go b/tpl/internal/go_templates/texttemplate/parse/parse.go
index 87b7618f7..d43d5334b 100644
--- a/tpl/internal/go_templates/texttemplate/parse/parse.go
+++ b/tpl/internal/go_templates/texttemplate/parse/parse.go
@@ -223,6 +223,11 @@ func (t *Tree) startParse(funcs []map[string]any, lex *lexer, treeSet map[string
 	t.vars = []string{"$"}
 	t.funcs = funcs
 	t.treeSet = treeSet
+	lex.options = lexOptions{
+		emitComment: t.Mode&ParseComments != 0,
+		breakOK:     !t.hasFunction("break"),
+		continueOK:  !t.hasFunction("continue"),
+	}
 }
 
 // stopParse terminates parsing.
@@ -241,11 +246,6 @@ func (t *Tree) Parse(text, leftDelim, rightDelim string, treeSet map[string]*Tre
 	defer t.recover(&err)
 	t.ParseName = t.Name
 	lexer := lex(t.Name, text, leftDelim, rightDelim)
-	lexer.options = lexOptions{
-		emitComment: t.Mode&ParseComments != 0,
-		breakOK:     !t.hasFunction("break"),
-		continueOK:  !t.hasFunction("continue"),
-	}
 	t.startParse(funcs, lexer, treeSet)
 	t.text = text
 	t.parse()
diff --git a/tpl/internal/go_templates/texttemplate/parse/parse_test.go b/tpl/internal/go_templates/texttemplate/parse/parse_test.go
index 6ab48b3f7..080eea2f9 100644
--- a/tpl/internal/go_templates/texttemplate/parse/parse_test.go
+++ b/tpl/internal/go_templates/texttemplate/parse/parse_test.go
@@ -394,6 +394,36 @@ func TestParseWithComments(t *testing.T) {
 	}
 }
 
+func TestKeywordsAndFuncs(t *testing.T) {
+	// Check collisions between functions and new keywords like 'break'. When a
+	// break function is provided, the parser should treat 'break' as a function,
+	// not a keyword.
+	textFormat = "%q"
+	defer func() { textFormat = "%s" }()
+
+	inp := `{{range .X}}{{break 20}}{{end}}`
+	{
+		// 'break' is a defined function, don't treat it as a keyword: it should
+		// accept an argument successfully.
+		var funcsWithKeywordFunc = map[string]any{
+			"break": func(in any) any { return in },
+		}
+		tmpl, err := New("").Parse(inp, "", "", make(map[string]*Tree), funcsWithKeywordFunc)
+		if err != nil || tmpl == nil {
+			t.Errorf("with break func: unexpected error: %v", err)
+		}
+	}
+
+	{
+		// No function called 'break'; treat it as a keyword. Results in a parse
+		// error.
+		tmpl, err := New("").Parse(inp, "", "", make(map[string]*Tree), make(map[string]any))
+		if err == nil || tmpl != nil {
+			t.Errorf("without break func: expected error; got none")
+		}
+	}
+}
+
 func TestSkipFuncCheck(t *testing.T) {
 	oldTextFormat := textFormat
 	textFormat = "%q"