Set the time zone in main and run Entry in its own test process (closes #192)

cli.Entry() set time.Local to UTC and ended with memguard.Purge(), and
TestEntryWipesBuffersAndReturnsExitCode ran it in the same process as
the other tests. A timer left by an earlier test could read time.Local
as it changed, which the race detector reported on some runs, and the
purge could destroy a buffer still in use, the likeliest cause of a
crash seen on another run.

main() in cmd/secret now sets time.Local before it calls cli.Entry();
the test that runs the built binary with TZ=America/New_York still
covers it. The Entry test runs cli.Entry() in a copy of the test binary
started with SECRET_TEST_RUN_ENTRY set, which init picks up so that
TestMain does not run there.

Model: opus-5-5

TODO.md

@@ -18,6 +18,15 @@ https://git.eeqj.de/sneak/secret/milestone/12
 
 # Completed Steps
 
+- 2026-10-15: `make test` no longer fails on some runs in `internal/cli`
+  (https://git.eeqj.de/sneak/secret/issues/192). `cli.Entry()` set `time.Local`
+  to UTC and ended by wiping every memguard buffer, and a test ran it in the
+  same process as the other tests. A timer left by an earlier test could read
+  `time.Local` as it changed, which the race detector reported, and the wipe
+  could destroy a buffer still in use, the likeliest cause of a crash of the
+  test process on another run. `main()` in `cmd/secret` now sets `time.Local`
+  before it calls `cli.Entry()`, and that test runs `cli.Entry()` in a process
+  of its own.
 - 2026-10-14: A wrong passphrase, from `SB_UNLOCK_PASSPHRASE` or typed at the
   prompt, gives the error `wrong passphrase for unlocker <id>`
   (https://git.eeqj.de/sneak/secret/issues/157). It used to be age's "no

cmd/secret/main.go

@@ -3,10 +3,16 @@ package main
 
 import (
 	"os"
+	"time"
 
 	"sneak.berlin/go/secret/internal/cli"
 )
 
 func main() {
+	// Every time secret prints or writes is in UTC, whatever TZ or the
+	// system's time zone is set to. It is set here, before cli.Entry starts
+	// any goroutine that could read time.Local while it changes.
+	time.Local = time.UTC //nolint:gosmopolitan // this makes local time UTC
+
 	os.Exit(cli.Entry())
 }

internal/cli/entry_test.go

@@ -3,6 +3,7 @@ package cli_test
 import (
 	"bufio"
 	"context"
+	"fmt"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -16,29 +17,66 @@ import (
 	"sneak.berlin/go/secret/internal/secret"
 )
 
-// Entry must return its exit code rather than exit, so that its deferred
-// memguard purge runs on the success and the error path alike.
-//
-//nolint:paralleltest // sets os.Args, and Entry wipes every buffer in the process
-func TestEntryWipesBuffersAndReturnsExitCode(t *testing.T) {
-	savedArgs := os.Args
+const (
+	// envRunEntry, when set, makes this test binary run cli.Entry with its
+	// own arguments and exit, instead of running the tests.
+	envRunEntry = "SECRET_TEST_RUN_ENTRY"
 
-	t.Cleanup(func() { os.Args = savedArgs })
+	// bufferWiped is what the test binary prints, run with envRunEntry set,
+	// when cli.Entry wiped the buffer made before it ran.
+	bufferWiped = "Entry wiped the buffer made before it ran"
+)
+
+// With envRunEntry set, the test binary makes a buffer, runs cli.Entry,
+// says whether the buffer is wiped, and exits with Entry's exit code. This
+// is done in init, not in a test, so that TestMain does not run in that
+// process: it would build the secret binary again, and remove it at the end,
+// while the other tests run it.
+//
+//nolint:gochecknoinits // must run before TestMain, as above
+func init() {
+	if os.Getenv(envRunEntry) == "" {
+		return
+	}
+
+	buf := memguard.NewBufferFromBytes([]byte("key material"))
+	code := cli.Entry()
+
+	if !buf.IsAlive() {
+		fmt.Fprintln(os.Stderr, bufferWiped)
+	}
+
+	os.Exit(code)
+}
+
+// Entry must return its exit code rather than exit, so that its deferred
+// memguard purge runs on the success and the error path alike. Entry wipes
+// every memguard buffer in the process, including those other tests are
+// using, so it runs in a process of its own: this test binary, run again
+// with envRunEntry set.
+func TestEntryWipesBuffersAndReturnsExitCode(t *testing.T) {
+	t.Parallel()
 
 	tests := []struct {
 		args     []string
 		exitCode int
 	}{
-		{args: []string{"secret", "--help"}, exitCode: 0},
-		{args: []string{"secret", "no-such-command"}, exitCode: 1},
+		{args: []string{"--help"}, exitCode: 0},
+		{args: []string{"no-such-command"}, exitCode: 1},
 	}
 
 	for _, tt := range tests {
-		buf := memguard.NewBufferFromBytes([]byte("key material"))
-		os.Args = tt.args
+		//nolint:gosec // G204: test runs its own test binary
+		cmd := exec.CommandContext(t.Context(), os.Args[0], tt.args...)
+		cmd.Env = append(os.Environ(), envRunEntry+"=1")
 
-		assert.Equal(t, tt.exitCode, cli.Entry(), "exit code for %v", tt.args)
-		assert.False(t, buf.IsAlive(), "Entry left a buffer unwiped for %v", tt.args)
+		output, err := cmd.CombinedOutput()
+		require.NotNil(t, cmd.ProcessState, "%v did not run: %v", tt.args, err)
+
+		assert.Equal(t, tt.exitCode, cmd.ProcessState.ExitCode(),
+			"exit code for %v: %s", tt.args, output)
+		assert.Contains(t, string(output), bufferWiped,
+			"Entry left a buffer unwiped for %v", tt.args)
 	}
 }
 

internal/cli/root.go

@@ -2,7 +2,6 @@ package cli
 
 import (
 	"os"
-	"time"
 
 	"github.com/awnumar/memguard"
 	"github.com/spf13/cobra"
@@ -15,10 +14,6 @@ import (
 // every memguard buffer before it returns, so the caller must do nothing
 // but exit with the code.
 func Entry() int {
-	// Every time secret prints or writes is in UTC, whatever TZ or the
-	// system's time zone is set to.
-	time.Local = time.UTC //nolint:gosmopolitan // this makes local time UTC
-
 	raiseLockedMemoryLimit()
 
 	// On SIGINT or SIGTERM memguard runs this function, wipes every buffer