From 16e012539918f43b1920ab4dba841fd3476b0cae Mon Sep 17 00:00:00 2001
From: Tim Smith <tim@mondoo.com>
Date: Mon, 7 Sep 2026 23:14:32 -0700
Subject: [PATCH] fix(config): stop `config create` spinning forever on closed
 stdin

`promptNoDefault` swallowed io.EOF and returned an empty string, so the
"New profile name" loop in `promptExistingFileAction` rejected the empty
answer and asked again, forever. Running `cinc config create < /dev/null`
against a credentials file that already had profiles pinned a core and
flooded stdout: a probe measured 57 million prompts in 20 seconds.

The action prompt defaults to "Add a new profile", so nothing unusual is
needed to reach it: any non-interactive invocation with an existing
credentials file hangs.

`promptNoDefault` now separates the two cases a bare `""` used to
conflate. An empty line is still a real answer (the collision and replace
prompts treat Enter as their default), but a reader with nothing left to
give returns errStdinExhausted, which names the flags that configure a
profile without prompting.

`promptWithDefault` is deliberately unchanged: falling back to the
default on EOF is what lets the onboarding flow accept defaults, and it
cannot loop.

Signed-off-by: Tim Smith <tim@mondoo.com>
---
 apps/cinc/cmd/create.go      | 13 +++++++++++
 apps/cinc/cmd/create_test.go | 43 ++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/apps/cinc/cmd/create.go b/apps/cinc/cmd/create.go
index e43b906..cead7f7 100644
--- a/apps/cinc/cmd/create.go
+++ b/apps/cinc/cmd/create.go
@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"io"
 	"net/url"
@@ -386,12 +387,24 @@ func splitChefServerURL(raw string) (host, org string) {
 	return u.Host, ""
 }
 
+// errStdinExhausted is returned by promptNoDefault when there is no input
+// left to read. The prompts that have no sensible default re-ask until they
+// get an answer, so without this the flow would spin forever against a
+// closed stdin (`cinc config create < /dev/null`, or a CI run).
+var errStdinExhausted = errors.New("we ran out of input while waiting for an answer. `cinc config create` needs an interactive terminal; to configure without prompts, pass --client-name, --client-key, and --server-url")
+
+// promptNoDefault asks for an answer that has no default. An empty line is a
+// valid (if usually rejected) answer, so it is reported as one; only a reader
+// with nothing left to give yields errStdinExhausted.
 func promptNoDefault(reader *bufio.Reader, out io.Writer, label string) (string, error) {
 	fmt.Fprintf(out, "%s: ", label)
 	answer, err := reader.ReadString('\n')
 	if err != nil && err != io.EOF {
 		return "", err
 	}
+	if err == io.EOF && answer == "" {
+		return "", errStdinExhausted
+	}
 	return strings.TrimSpace(answer), nil
 }
 
diff --git a/apps/cinc/cmd/create_test.go b/apps/cinc/cmd/create_test.go
index 84bb650..02d9a02 100644
--- a/apps/cinc/cmd/create_test.go
+++ b/apps/cinc/cmd/create_test.go
@@ -6,10 +6,53 @@ import (
 	"path/filepath"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/cinc-project/cinc-cli/cli/config"
 )
 
+// TestConfigureStopsWhenStdinIsExhausted covers `cinc config create` run
+// without an interactive terminal (for example `cinc config create <
+// /dev/null`, or from CI) against a credentials file that already holds
+// profiles. The action prompt defaults to "Add a new profile", which then
+// asks for a name it will not accept as empty. With no more input to read
+// the command has to give up with a clear error rather than re-asking forever.
+func TestConfigureStopsWhenStdinIsExhausted(t *testing.T) {
+	dir := t.TempDir()
+	cfgPath := filepath.Join(dir, "credentials")
+	if err := config.WriteProfile(cfgPath, "default", config.Profile{
+		ServerURL:  "https://old.example.test",
+		Org:        "old",
+		ClientName: "old",
+		KeyPath:    "/keys/old.pem",
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	root := newRootCmd()
+	var out bytes.Buffer
+	root.SetOut(&out)
+	root.SetErr(new(bytes.Buffer))
+	root.SetIn(strings.NewReader(""))
+	root.SetArgs([]string{"config", "create", "--config", cfgPath})
+
+	done := make(chan error, 1)
+	go func() { done <- root.Execute() }()
+
+	select {
+	case err := <-done:
+		if err == nil {
+			t.Fatal("expected an error when stdin is exhausted, got nil")
+		}
+		if !strings.Contains(err.Error(), "ran out of input") {
+			t.Fatalf("error = %v, want it to explain that input ran out", err)
+		}
+	case <-time.After(10 * time.Second):
+		t.Fatalf("config create never returned; it asked for a profile name %d times",
+			strings.Count(out.String(), "New profile name"))
+	}
+}
+
 func TestConfigureCommandWritesTOMLCredentialsProfile(t *testing.T) {
 	dir := t.TempDir()
 	cfgPath := filepath.Join(dir, "credentials")