cmd/doc: fix "builtin" package parsing

As stated in the code, "The builtin package needs special treatment: its
symbols are lower case but we want to see them, always". Thus, cmd/doc
forces the -u flag if the package being queried is called "builtin".
However, this happens after having already parsed the package. This
CL forces the -u flag just after parsing the command arguments and
before parsing any package.

Fixes #49796.

Change-Id: If690a900c7cfd1700feecb9529bd4344c3c249d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/367134
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>

diff --git a/src/cmd/doc/main.go b/src/cmd/doc/main.go
index 0499c403695247035687054c0700fe28500a0b57..dee5d7bbcd7142d07c822387d2b42d6ce65fa522 100644 (file)
--- a/src/cmd/doc/main.go
+++ b/src/cmd/doc/main.go
@@ -110,6 +110,13 @@ func do(writer io.Writer, flagSet *flag.FlagSet, args []string) (err error) {
                if buildPackage == nil {
                        return fmt.Errorf("no such package: %s", userPath)
                }
+
+               // The builtin package needs special treatment: its symbols are lower
+               // case but we want to see them, always.
+               if buildPackage.ImportPath == "builtin" {
+                       unexported = true
+               }
+
                symbol, method = parseSymbol(sym)
                pkg := parsePackage(writer, buildPackage, userPath)
                paths = append(paths, pkg.prettyPath())
@@ -128,12 +135,6 @@ func do(writer io.Writer, flagSet *flag.FlagSet, args []string) (err error) {
                        panic(e)
                }()
 
-               // The builtin package needs special treatment: its symbols are lower
-               // case but we want to see them, always.
-               if pkg.build.ImportPath == "builtin" {
-                       unexported = true
-               }
-
                // We have a package.
                if showAll && symbol == "" {
                        pkg.allDoc()