fix: Suppress non-PMG error from Critical UI Error (#311)

* fix: Suppress non-PMG error from Critical UI Error

* fix: Code review fixes

---------

Co-authored-by: Sahil Bansal <bansalsahil315@gmail.com>

internal/runner/childexit_test.go

@@ -0,0 +1,103 @@
+package runner
+
+import (
+	"errors"
+	"os/exec"
+	"testing"
+
+	"github.com/safedep/dry/usefulerror"
+	"github.com/safedep/pmg/errcodes"
+	"github.com/safedep/pmg/internal/pty"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestExtractExit(t *testing.T) {
+	t.Run("direct non-zero exit resolves the real code", func(t *testing.T) {
+		err := exec.Command("sh", "-c", "exit 2").Run()
+		require.Error(t, err)
+
+		code, signaled, resolved := extractExit(err)
+		assert.Equal(t, 2, code)
+		assert.False(t, signaled)
+		assert.True(t, resolved)
+	})
+
+	t.Run("direct signal termination resolves to 128+signum", func(t *testing.T) {
+		err := exec.Command("sh", "-c", "kill -INT $$").Run()
+		require.Error(t, err)
+
+		code, signaled, resolved := extractExit(err)
+		assert.Equal(t, 130, code) // 128 + SIGINT(2)
+		assert.True(t, signaled)
+		assert.True(t, resolved)
+	})
+
+	t.Run("pty exit error reads its fields directly", func(t *testing.T) {
+		code, signaled, resolved := extractExit(&pty.ExitError{Code: 1})
+		assert.Equal(t, 1, code)
+		assert.False(t, signaled)
+		assert.True(t, resolved)
+
+		code, signaled, resolved = extractExit(&pty.ExitError{Code: 143, Signaled: true})
+		assert.Equal(t, 143, code)
+		assert.True(t, signaled)
+		assert.True(t, resolved)
+	})
+
+	t.Run("non-exit error is unresolved", func(t *testing.T) {
+		_, _, resolved := extractExit(errors.New("failed to launch binary"))
+		assert.False(t, resolved)
+	})
+}
+
+func TestDecideExit(t *testing.T) {
+	runErr := errors.New("npm failed")
+
+	t.Run("plain child exit becomes a transparent ChildExitError", func(t *testing.T) {
+		err := decideExit(runErr, 1, false, true, "npm")
+
+		var ce *ChildExitError
+		require.True(t, errors.As(err, &ce))
+		assert.Equal(t, 1, ce.ExitCode())
+		assert.True(t, ce.Transparent())
+		assert.False(t, ce.IsSignaled())
+		assert.Equal(t, "npm", ce.PMName)
+	})
+
+	t.Run("signaled child exit is transparent and signaled", func(t *testing.T) {
+		err := decideExit(runErr, 130, true, true, "npm")
+
+		var ce *ChildExitError
+		require.True(t, errors.As(err, &ce))
+		assert.True(t, ce.IsSignaled())
+		assert.Equal(t, 130, ce.ExitCode())
+	})
+
+	t.Run("unresolved exit is a visible launch failure", func(t *testing.T) {
+		err := decideExit(runErr, -1, false, false, "npm")
+
+		usefulErr, ok := usefulerror.AsUsefulError(err)
+		require.True(t, ok)
+		assert.Equal(t, errcodes.PackageManagerExecutionFailed, usefulErr.Code())
+		assert.Equal(t, "Failed to execute package manager command", usefulErr.HumanError())
+
+		var ce *ChildExitError
+		assert.False(t, errors.As(err, &ce))
+	})
+}
+
+// classify is pure: a child that produced its own exit status is always a
+// transparent passthrough. Sandbox denials are persisted by the caller and
+// never reach classify, so they cannot make the exit loud (issue #309).
+func TestClassifyTransparentChildExit(t *testing.T) {
+	childErr := exec.Command("sh", "-c", "exit 1").Run()
+	require.Error(t, childErr)
+
+	err := classify(childErr, "npm")
+
+	var ce *ChildExitError
+	require.True(t, errors.As(err, &ce))
+	assert.Equal(t, 1, ce.ExitCode())
+	assert.Equal(t, "npm", ce.PMName)
+}