all: start suggesting Go 1.21 and testing on it

Also note that the first release is now 1.21.0,
so we no longer need to use the awkward 1.21.x notation in warnings.

.github/workflows/test.yml

@@ -25,7 +25,7 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.20.x]
+        go-version: [1.20.x, 1.21.x]
         os: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     steps:
@@ -53,17 +53,17 @@ jobs:
     # Static checks from this point forward. Only run on one Go version and on
     # linux, since it's the fastest platform, and the tools behave the same.
     - name: Test third-party project builds
-      if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.20.x'
+      if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.21.x'
       run: |
         go install
         ./scripts/check-third-party.sh
-    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.20.x'
+    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.21.x'
       run: ./scripts/crlf-test.sh
-    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.20.x'
+    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.21.x'
       run: diff <(echo -n) <(gofmt -d .)
-    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.20.x'
+    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.21.x'
       run: go vet ./...
-    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.20.x'
+    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.21.x'
       uses: dominikh/staticcheck-action@v1
       with:
         version: "2023.1.3"
@@ -81,11 +81,12 @@ jobs:
     - uses: actions/checkout@v3
     - uses: actions/setup-go@v4
       with:
-        go-version: 1.20.x
+        go-version: 1.21.x
         cache: false
     - run: go test -short ./...
 
   test-gotip:
+    if: false # let tip for 1.22 settle first
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3

main.go

@@ -268,7 +268,7 @@ func (e errJustExit) Error() string { return fmt.Sprintf("exit: %d", e) }
 func goVersionOK() bool {
 	const (
 		minGoVersionSemver = "v1.20.0"
-		suggestedGoVersion = "1.20.x"
+		suggestedGoVersion = "1.21"
 	)
 
 	// rxVersion looks for a version like "go1.2" or "go1.2.3"

testdata/script/goversion.txtar

@@ -7,30 +7,30 @@ env PATH=${WORK}/.bin${:}${PATH}
 # An empty go version.
 env TOOLCHAIN_GOVERSION=''
 ! exec garble build
-stderr 'Go version is too old; please upgrade to Go 1\.20\.x or newer'
+stderr 'Go version is too old; please upgrade to Go 1\.21 or newer'
 
 # We should error on a devel version that's too old.
 # Note that they lacked the "goN.M-" prefix.
 env TOOLCHAIN_GOVERSION='devel +afb5fca Sun Aug 07 00:00:00 2020 +0000'
 ! exec garble build
-stderr 'Go version is too old; please upgrade to Go 1\.20\.x or newer'
+stderr 'Go version is too old; please upgrade to Go 1\.21 or newer'
 
 # Another form of old version; with an old "goN.M-" prefix.
 env TOOLCHAIN_GOVERSION='devel go1.15-afb5fca Sun Aug 07 00:00:00 2020 +0000'
 ! exec garble build
-stderr 'Go version "devel go1\.15-.*2020.*" is too old; please upgrade to Go 1\.20\.x'
+stderr 'Go version "devel go1\.15-.*2020.*" is too old; please upgrade to Go 1\.21'
 
 # A current devel version should be fine.
 # Note that we don't look at devel version timestamps.
-env GARBLE_TEST_GOVERSION='go1.20'
-env TOOLCHAIN_GOVERSION='devel go1.20-ad97d204f0 Sun Sep 12 16:46:58 2023 +0000'
+env GARBLE_TEST_GOVERSION='go1.21'
+env TOOLCHAIN_GOVERSION='devel go1.21-ad97d204f0 Sun Sep 12 16:46:58 2023 +0000'
 ! exec garble build
 stderr 'mocking the real build'
 
 # We should error on a stable version that's too old.
 env TOOLCHAIN_GOVERSION='go1.14'
 ! exec garble build
-stderr 'Go version "go1\.14" is too old; please upgrade to Go 1\.20\.x or newer'
+stderr 'Go version "go1\.14" is too old; please upgrade to Go 1\.21 or newer'
 
 # We should accept a future stable version.
 # Note that we need to bump the version of Go that supposedly built it, too.