When we get the signed binaries back, the signing process has modified
the tarball somewhat. We want the files to match as much as possible, so
undo those changes. (And avoid making one change ourselves.)

- Don't add a directory entry for the go/ root dir. It's unnecessary and
  not included in distpacks. This will affect non-distpack builds, but
  nobody is scrutinizing those.
- Remove all other the directory entries too, which were inserted by the
  signing process.
- Set the timestamps back to the distribution's timestamps.
- Clear the user information on the modified files.

For golang/go#61513

Change-Id: I0b3508bc2547364e2a2b49e1c6ea7be8fe92b308
Reviewed-on: https://go-review.googlesource.com/c/build/+/511759
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Heschi Kreinick <heschi@google.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

Trying to predict the format of the distpack archives was probably not a
good idea. Use the same approach we use for the module zips: tweak the
contents of the files, and leave the metadata untouched.

For golang/go#61513

Change-Id: I6e498b573eade71ec907590af05e7d3c0f25eb57
Reviewed-on: https://go-review.googlesource.com/c/build/+/512437
Auto-Submit: Heschi Kreinick <heschi@google.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

The code was sorting files in the archives entirely by path string,
but that's not what fs.WalkDir would do. In a directory with
subdirectory foo/bar and file foo/bar.go, foo/bar gets visited
first, so foo/bar/baz appears before foo/bar.go, even though
"foo/bar/baz" > "foo/bar.go".

This CL replaces the string comparison with a path-aware
comparison that places foo/bar/baz before foo/bar.go,
so that if the tar file is extracted and then repacked using
fs.WalkDir, the files will remain in the same order.

This will make it easier to compare the pristine distpack-produced
tgz for darwin against the rebuilt tgz with signed binaries.

Before:
% tar tzvf /tmp/cmddist.tgz | grep -C1 runtime/cgo.go
-rw-r--r--  0 0      0       11122 Jul 13 15:00 go/src/runtime/callers_test.go
-rw-r--r--  0 0      0        2416 Jul 13 15:00 go/src/runtime/cgo.go
-rw-r--r--  0 0      0        2795 Jul 13 15:00 go/src/runtime/cgo/abi_amd64.h

After:
% tar tzvf pkg/distpack/go1.21rsc.src.tar.gz | grep -C1 runtime/cgo.go
-rw-r--r--  0 0      0        1848 Dec 31  1969 go/src/runtime/cgo/signal_ios_arm64.s
-rw-r--r--  0 0      0        2416 Dec 31  1969 go/src/runtime/cgo.go
-rw-r--r--  0 0      0        2479 Dec 31  1969 go/src/runtime/cgo_mmap.go

For #24904.
For #61513.

Change-Id: Ib7374bc0d6324377f81c561bef57fd87b2111b98
Reviewed-on: https://go-review.googlesource.com/c/go/+/511977
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

Issue 61513 is resolved so this path can be turned on now.
Confirmed to still pass now that go1.21rc4 is out. It was
the first release built using improvements from CL 512437.

For golang/go#57120.
For golang/go#58884.
For golang/go#61513.

Change-Id: Ie39765f8c7ba514dea2bfccf7c8ef8acc5822a22
Reviewed-on: https://go-review.googlesource.com/c/build/+/515415
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Auto-Submit: Russ Cox <rsc@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>

Caught while working on go.dev/issue/63147.

For golang/go#61513.

Change-Id: Ied9d3a6716759dfe40bf224f6b60bf733e07dc13
Cq-Include-Trybots: luci.golang.try:x_build-gotip-linux-amd64-longtest-race
Reviewed-on: https://go-review.googlesource.com/c/build/+/552015
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>