Unmarshal a number as a Number in RawInspectFallback

Running `docker inspect --format "{{.ID}} {{.Size}}" alpine` prints
sha256:651aa95985aa4a17a38ffcf71f598ec461924ca96865facc2c5782ef2d2be07f 3983636
While `docker inspect --format "{{.Id}} {{.Size}}" alpine` prints
sha256:651aa95985aa4a17a38ffcf71f598ec461924ca96865facc2c5782ef2d2be07f 3.983636e+06

This happens because "Id" is not a field of types.ImageInspect and thus
tryRawInspectFallback is called and converts the raw response into `interface{}`
using a JSON decoder. However, by default that decoder converts numbers into
`float64` unless `UseNumber` is set.

Signed-off-by: Boaz Shuster <ripcurld.github@gmail.com>

cli/command/inspect/inspector.go

@@ -110,6 +110,7 @@ func (i *TemplateInspector) tryRawInspectFallback(rawElement []byte) error {
 	buffer := new(bytes.Buffer)
 	rdr := bytes.NewReader(rawElement)
 	dec := json.NewDecoder(rdr)
+	dec.UseNumber()
 
 	if rawErr := dec.Decode(&raw); rawErr != nil {
 		return errors.Errorf("unable to read inspect data: %v", rawErr)

cli/command/inspect/inspector_test.go

@@ -6,6 +6,8 @@ import (
 	"testing"
 
 	"github.com/docker/docker/pkg/templates"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 type testElement struct {
@@ -219,3 +221,39 @@ func TestIndentedInspectorRawElements(t *testing.T) {
 		t.Fatalf("Expected `%s`, got `%s`", expected, b.String())
 	}
 }
+
+// moby/moby#32235
+// This test verifies that even if `tryRawInspectFallback` is called the fields containing
+// numerical values are displayed correctly.
+// For example, `docker inspect --format "{{.Id}} {{.Size}} alpine` and
+// `docker inspect --format "{{.ID}} {{.Size}} alpine" will have the same output which is
+// sha256:651aa95985aa4a17a38ffcf71f598ec461924ca96865facc2c5782ef2d2be07f 3983636
+func TestTemplateInspectorRawFallbackNumber(t *testing.T) {
+	// Using typedElem to automatically fall to tryRawInspectFallback.
+	typedElem := struct {
+		ID string `json:"Id"`
+	}{"ad3"}
+	testcases := []struct {
+		raw []byte
+		exp string
+	}{
+		{raw: []byte(`{"Id": "ad3", "Size": 53317}`), exp: "53317 ad3\n"},
+		{raw: []byte(`{"Id": "ad3", "Size": 53317.102}`), exp: "53317.102 ad3\n"},
+		{raw: []byte(`{"Id": "ad3", "Size": 53317.0}`), exp: "53317.0 ad3\n"},
+	}
+	b := new(bytes.Buffer)
+	tmpl, err := templates.Parse("{{.Size}} {{.Id}}")
+	require.NoError(t, err)
+
+	i := NewTemplateInspector(b, tmpl)
+	for _, tc := range testcases {
+		err = i.Inspect(typedElem, tc.raw)
+		require.NoError(t, err)
+
+		err = i.Flush()
+		require.NoError(t, err)
+
+		assert.Equal(t, tc.exp, b.String())
+		b.Reset()
+	}
+}