Generate the README's --help output automatically via cargo +nightly dev generate-all (#1483)

README.md

@@ -300,13 +300,14 @@ ruff path/to/code/ --select F401 --select F403
 
 See `ruff --help` for more:
 
+<!-- Begin auto-generated cli help. -->
 ```shell
 Ruff: An extremely fast Python linter.
 
 Usage: ruff [OPTIONS] [FILES]...
 
 Arguments:
-  [FILES]...
+  [FILES]...  
 
 Options:
       --config <CONFIG>
@@ -381,7 +382,9 @@ Options:
           Print help information
   -V, --version
           Print version information
+
 ```
+<!-- End auto-generated cli help. -->
 
 ### `pyproject.toml` discovery
 
@@ -1669,7 +1672,6 @@ Summary
 
 <!-- Sections automatically generated by `cargo dev generate-options`. -->
 <!-- Begin auto-generated options sections. -->
-
 #### [`allowed-confusables`](#allowed-confusables)
 
 A list of allowed "confusable" Unicode characters to ignore when

ruff_dev/src/generate_all.rs

@@ -4,7 +4,8 @@ use anyhow::Result;
 use clap::Args;
 
 use crate::{
-    generate_check_code_prefix, generate_json_schema, generate_options, generate_rules_table,
+    generate_check_code_prefix, generate_cli_help, generate_json_schema, generate_options,
+    generate_rules_table,
 };
 
 #[derive(Args)]
@@ -27,5 +28,8 @@ pub fn main(cli: &Cli) -> Result<()> {
     generate_options::main(&generate_options::Cli {
         dry_run: cli.dry_run,
     })?;
+    generate_cli_help::main(&generate_cli_help::Cli {
+        dry_run: cli.dry_run,
+    })?;
     Ok(())
 }

ruff_dev/src/generate_cli_help.rs

@@ -0,0 +1,34 @@
+//! Generate CLI help.
+
+use anyhow::Result;
+use clap::{Args, CommandFactory};
+use ruff::cli::Cli as MainCli;
+
+use crate::utils::replace_readme_section;
+
+const HELP_BEGIN_PRAGMA: &str = "<!-- Begin auto-generated cli help. -->";
+const HELP_END_PRAGMA: &str = "<!-- End auto-generated cli help. -->";
+
+#[derive(Args)]
+pub struct Cli {
+    /// Write the generated help to stdout (rather than to `README.md`).
+    #[arg(long)]
+    pub(crate) dry_run: bool,
+}
+
+pub fn main(cli: &Cli) -> Result<()> {
+    let mut cmd = MainCli::command();
+    let output = cmd.render_help().to_string();
+
+    if cli.dry_run {
+        print!("{output}");
+    } else {
+        replace_readme_section(
+            &format!("```shell\n{output}\n```\n"),
+            HELP_BEGIN_PRAGMA,
+            HELP_END_PRAGMA,
+        )?;
+    }
+
+    Ok(())
+}

ruff_dev/src/generate_options.rs

@@ -1,16 +1,13 @@
 //! Generate a Markdown-compatible listing of configuration options.
 
-use std::fs;
-use std::fs::OpenOptions;
-use std::io::Write;
-use std::path::PathBuf;
-
 use anyhow::Result;
 use clap::Args;
 use itertools::Itertools;
 use ruff::settings::options::Options;
 use ruff::settings::options_base::{ConfigurationOptions, OptionEntry, OptionField};
 
+use crate::utils::replace_readme_section;
+
 const BEGIN_PRAGMA: &str = "<!-- Begin auto-generated options sections. -->";
 const END_PRAGMA: &str = "<!-- End auto-generated options sections. -->";
 
@@ -95,30 +92,7 @@ pub fn main(cli: &Cli) -> Result<()> {
     if cli.dry_run {
         print!("{output}");
     } else {
-        // Read the existing file.
-        let file = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
-            .parent()
-            .expect("Failed to find root directory")
-            .join("README.md");
-        let existing = fs::read_to_string(&file)?;
-
-        // Extract the prefix.
-        let index = existing
-            .find(BEGIN_PRAGMA)
-            .expect("Unable to find begin pragma");
-        let prefix = &existing[..index + BEGIN_PRAGMA.len()];
-
-        // Extract the suffix.
-        let index = existing
-            .find(END_PRAGMA)
-            .expect("Unable to find end pragma");
-        let suffix = &existing[index..];
-
-        // Write the prefix, new contents, and suffix.
-        let mut f = OpenOptions::new().write(true).truncate(true).open(&file)?;
-        write!(f, "{prefix}\n\n")?;
-        write!(f, "{output}")?;
-        write!(f, "{suffix}")?;
+        replace_readme_section(&output, BEGIN_PRAGMA, END_PRAGMA)?;
     }
 
     Ok(())

ruff_dev/src/generate_rules_table.rs

@@ -1,16 +1,13 @@
 //! Generate a Markdown-compatible table of supported lint rules.
 
-use std::fs;
-use std::fs::OpenOptions;
-use std::io::Write;
-use std::path::PathBuf;
-
 use anyhow::Result;
 use clap::Args;
 use itertools::Itertools;
 use ruff::checks::{CheckCategory, CheckCode};
 use strum::IntoEnumIterator;
 
+use crate::utils::replace_readme_section;
+
 const TABLE_BEGIN_PRAGMA: &str = "<!-- Begin auto-generated sections. -->";
 const TABLE_END_PRAGMA: &str = "<!-- End auto-generated sections. -->";
 
@@ -85,32 +82,3 @@ pub fn main(cli: &Cli) -> Result<()> {
 
     Ok(())
 }
-
-fn replace_readme_section(content: &str, begin_pragma: &str, end_pragma: &str) -> Result<()> {
-    // Read the existing file.
-    let file = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
-        .parent()
-        .expect("Failed to find root directory")
-        .join("README.md");
-    let existing = fs::read_to_string(&file)?;
-
-    // Extract the prefix.
-    let index = existing
-        .find(begin_pragma)
-        .expect("Unable to find begin pragma");
-    let prefix = &existing[..index + begin_pragma.len()];
-
-    // Extract the suffix.
-    let index = existing
-        .find(end_pragma)
-        .expect("Unable to find end pragma");
-    let suffix = &existing[index..];
-
-    // Write the prefix, new contents, and suffix.
-    let mut f = OpenOptions::new().write(true).truncate(true).open(&file)?;
-    writeln!(f, "{prefix}")?;
-    write!(f, "{content}")?;
-    write!(f, "{suffix}")?;
-
-    Ok(())
-}

ruff_dev/src/lib.rs

@@ -13,6 +13,7 @@
 
 pub mod generate_all;
 pub mod generate_check_code_prefix;
+pub mod generate_cli_help;
 pub mod generate_json_schema;
 pub mod generate_options;
 pub mod generate_rules_table;
@@ -20,3 +21,4 @@ pub mod print_ast;
 pub mod print_cst;
 pub mod print_tokens;
 pub mod round_trip;
+mod utils;

ruff_dev/src/main.rs

@@ -14,8 +14,8 @@
 use anyhow::Result;
 use clap::{Parser, Subcommand};
 use ruff_dev::{
-    generate_all, generate_check_code_prefix, generate_json_schema, generate_options,
-    generate_rules_table, print_ast, print_cst, print_tokens, round_trip,
+    generate_all, generate_check_code_prefix, generate_cli_help, generate_json_schema,
+    generate_options, generate_rules_table, print_ast, print_cst, print_tokens, round_trip,
 };
 
 #[derive(Parser)]
@@ -38,6 +38,8 @@ enum Commands {
     GenerateRulesTable(generate_rules_table::Cli),
     /// Generate a Markdown-compatible listing of configuration options.
     GenerateOptions(generate_options::Cli),
+    /// Generate CLI help.
+    GenerateCliHelp(generate_cli_help::Cli),
     /// Print the AST for a given Python file.
     PrintAST(print_ast::Cli),
     /// Print the LibCST CST for a given Python file.
@@ -56,6 +58,7 @@ fn main() -> Result<()> {
         Commands::GenerateJSONSchema(args) => generate_json_schema::main(args)?,
         Commands::GenerateRulesTable(args) => generate_rules_table::main(args)?,
         Commands::GenerateOptions(args) => generate_options::main(args)?,
+        Commands::GenerateCliHelp(args) => generate_cli_help::main(args)?,
         Commands::PrintAST(args) => print_ast::main(args)?,
         Commands::PrintCST(args) => print_cst::main(args)?,
         Commands::PrintTokens(args) => print_tokens::main(args)?,

ruff_dev/src/utils.rs

@@ -0,0 +1,35 @@
+use std::fs;
+use std::fs::OpenOptions;
+use std::io::Write;
+use std::path::PathBuf;
+
+use anyhow::Result;
+
+pub fn replace_readme_section(content: &str, begin_pragma: &str, end_pragma: &str) -> Result<()> {
+    // Read the existing file.
+    let file = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .parent()
+        .expect("Failed to find root directory")
+        .join("README.md");
+    let existing = fs::read_to_string(&file)?;
+
+    // Extract the prefix.
+    let index = existing
+        .find(begin_pragma)
+        .expect("Unable to find begin pragma");
+    let prefix = &existing[..index + begin_pragma.len()];
+
+    // Extract the suffix.
+    let index = existing
+        .find(end_pragma)
+        .expect("Unable to find end pragma");
+    let suffix = &existing[index..];
+
+    // Write the prefix, new contents, and suffix.
+    let mut f = OpenOptions::new().write(true).truncate(true).open(&file)?;
+    writeln!(f, "{prefix}")?;
+    write!(f, "{content}")?;
+    write!(f, "{suffix}")?;
+
+    Ok(())
+}