Renaming --preview to --preview-format

This case study demonstrates using Renamify to rename a command-line argument across an entire codebase, including documentation, tests, and code.

Background

The initial code for the Renamify CLI had an inconsistency in its argument naming:

• The rename command used --preview to choose the preview format
• The plan command used --preview-format for the same purpose

I wanted to standardize on --preview by renaming the --preview-format argument in the plan command to match rename.

This refactoring involved:

• Updating the CLI argument definition in the Rust code
• Renaming test examples that use preview_format in compound matching tests
• Updating this documentation site (in ./docs)

Step 1: Renaming Test Examples

First, I needed to update the test cases in compound_matcher.rs and compound_position_test.rs that used preview_format strings as test data. (I had written extra tests during the initial attempt at this rename!) These tests verified compound word matching functionality and used:

find_compound_variants(
    "shouldPreviewFormatPlease",
    "preview_format",
    "preview",
    &styles,
);

I needed to change the test examples to use a different compound word that won’t conflict with our argument rename. I decided to rename “preview_format” to “foo_bar” and “preview” to “foo”.

./target/release/renamify rename preview_format foo_bar \
    renamify-core/tests/compound_position_test.rs

This one command replaced all of these variants in one shot, and all converted to the right case:

preview_format_arg, preview_format_option, previewFormatArg,
previewFormatOption, PreviewFormatArg, PreviewFormatOption,
preview_format, should_preview_format_please, get_preview_format_option,
shouldPreviewFormatPlease, getPreviewFormatOption, ShouldPreviewFormatPlease,
GetPreviewFormatOption, get_preview_format, load_preview_format,
getPreviewFormat, loadPreviewFormat, GetPreviewFormat, LoadPreviewFormat,
PreviewFormat, previewFormat

Then a preview => foo rename to handle the remaining cases:

./target/release/renamify rename preview foo \
    renamify-core/tests/compound_position_test.rs

Here’s the result:

I ran the tests and they all passed.

Step 2: Renaming the CLI Argument

Now I was able to rename the CLI argument:

./target/release/renamify rename preview-format preview

Some of the changes:

impl From<PreviewFormatArg> for PreviewFormat {
    fn from(arg: PreviewFormatArg) -> Self {
impl From<PreviewArg> for Preview {
    fn from(arg: PreviewArg) -> Self {
        match arg {
            PreviewFormatArg::Table => Self::Table,
            PreviewFormatArg::Diff => Self::Diff,
            PreviewFormatArg::Json => Self::Json,
            PreviewFormatArg::Summary => Self::Summary,
            PreviewFormatArg::None => Self::Table, // Default to table if None is somehow converted
            PreviewArg::Table => Self::Table,
            PreviewArg::Diff => Self::Diff,
            PreviewArg::Json => Self::Json,
            PreviewArg::Summary => Self::Summary,
            PreviewArg::None => Self::Table, // Default to table if None is somehow converted
        }
    }

...

@@ -658,7 +658,7 @@ fn handle_plan(
    include_styles: Vec<StyleArg>,
    only_styles: Vec<StyleArg>,
    exclude_match: Vec<String>,
    preview_format: PreviewFormat,
    preview: Preview,
    plan_out: PathBuf,
    dry_run: bool,
    use_color: bool,

A few minor issues to tidy up, then everything was done and all the tests were passing.