net/http/pprof: avoid panic with user-defined "GET /" route

With the new routing style in go 1.22, declaring

    http.Handle("GET /", h)

generates a conflict with route "/debug/pprof/" and the others declared in
the net/http/pprof package. You get an error such as:

panic: pattern "GET /" (registered at .../pprof.go:94): GET / matches
fewer methods than /debug/pprof/, but has a more general path pattern

This patch prevents that error.  Adding GET is correct because no other
method makes sense with the /debug/pprof routes. However, a tool using any
method other than GET will break.

We preserve the traditional behaviour when GODEBUG=httpmuxgo121=1 is
specified.

Updates #65723

Change-Id: I49c21f5f3e802ad7538062d824354b2e4d8a800e
GitHub-Last-Rev: 35e4012663f454fee8f00a321c43592ce4754feb
GitHub-Pull-Request: golang/go#65791
Reviewed-on: https://go-review.googlesource.com/c/go/+/565176
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
This commit is contained in:
Matteo Vaccari 2024-02-22 11:36:38 +00:00 committed by Jonathan Amsterdam
parent 0584574797
commit 9fcffc5359

View File

@ -8,6 +8,7 @@
// The package is typically only imported for the side effect of
// registering its HTTP handlers.
// The handled paths all begin with /debug/pprof/.
// As of Go 1.22, all the paths must be requested with GET.
//
// To use pprof, link this package into your program:
//
@ -75,6 +76,7 @@ import (
"context"
"fmt"
"html"
"internal/godebug"
"internal/profile"
"io"
"log"
@ -91,11 +93,15 @@ import (
)
func init() {
http.HandleFunc("/debug/pprof/", Index)
http.HandleFunc("/debug/pprof/cmdline", Cmdline)
http.HandleFunc("/debug/pprof/profile", Profile)
http.HandleFunc("/debug/pprof/symbol", Symbol)
http.HandleFunc("/debug/pprof/trace", Trace)
prefix := ""
if godebug.New("httpmuxgo121").Value() != "1" {
prefix = "GET "
}
http.HandleFunc(prefix+"/debug/pprof/", Index)
http.HandleFunc(prefix+"/debug/pprof/cmdline", Cmdline)
http.HandleFunc(prefix+"/debug/pprof/profile", Profile)
http.HandleFunc(prefix+"/debug/pprof/symbol", Symbol)
http.HandleFunc(prefix+"/debug/pprof/trace", Trace)
}
// Cmdline responds with the running program's