cli/command/container: deprecate NewDiffFormat

It's part of the presentation logic of the cli, and only used internally.
We can consider providing utilities for these, but better as part of
separate packages.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/command/container/diff.go

@@ -33,7 +33,7 @@ func runDiff(ctx context.Context, dockerCLI command.Cli, containerID string) err
 	}
 	diffCtx := formatter.Context{
 		Output: dockerCLI.Out(),
-		Format: NewDiffFormat("{{.Type}} {{.Path}}"),
+		Format: newDiffFormat("{{.Type}} {{.Path}}"),
 	}
 	return DiffFormatWrite(diffCtx, changes)
 }

cli/command/container/formatter_diff.go

@@ -13,7 +13,14 @@ const (
 )
 
 // NewDiffFormat returns a format for use with a diff Context
+//
+// Deprecated: this function was only used internally and will be removed in the next release.
 func NewDiffFormat(source string) formatter.Format {
+	return newDiffFormat(source)
+}
+
+// newDiffFormat returns a format for use with a diff [formatter.Context].
+func newDiffFormat(source string) formatter.Format {
 	if source == formatter.TableFormatKey {
 		return defaultDiffTableFormat
 	}

cli/command/container/formatter_diff_test.go

@@ -16,7 +16,7 @@ func TestDiffContextFormatWrite(t *testing.T) {
 		expected string
 	}{
 		{
-			formatter.Context{Format: NewDiffFormat("table")},
+			formatter.Context{Format: newDiffFormat("table")},
 			`CHANGE TYPE   PATH
 C             /var/log/app.log
 A             /usr/app/app.js
@@ -24,7 +24,7 @@ D             /usr/app/old_app.js
 `,
 		},
 		{
-			formatter.Context{Format: NewDiffFormat("table {{.Path}}")},
+			formatter.Context{Format: newDiffFormat("table {{.Path}}")},
 			`PATH
 /var/log/app.log
 /usr/app/app.js
@@ -32,7 +32,7 @@ D             /usr/app/old_app.js
 `,
 		},
 		{
-			formatter.Context{Format: NewDiffFormat("{{.Type}}: {{.Path}}")},
+			formatter.Context{Format: newDiffFormat("{{.Type}}: {{.Path}}")},
 			`C: /var/log/app.log
 A: /usr/app/app.js
 D: /usr/app/old_app.js