Delete Files Flag for Generate Command (#693)

* Generate now has a clear flag which will clear the output directory
before generating files

* Some change - will explain in PR description.

* Only delete files which were generated by SpacetimeDB

* Slightly better pattern matching to reduce false negatives or positives

* Added force command for CI

* Fix for help section

* Update crates/cli/src/subcommands/generate/mod.rs

Co-authored-by: Phoebe Goldman <[email protected]>
Signed-off-by: John Detter <[email protected]>

* Update crates/cli/src/subcommands/generate/mod.rs

Co-authored-by: Phoebe Goldman <[email protected]>
Signed-off-by: John Detter <[email protected]>

---------

Signed-off-by: John Detter <[email protected]>
Co-authored-by: John Detter <[email protected]>
Co-authored-by: Phoebe Goldman <[email protected]>

Author: jdetter

crates/cli/src/subcommands/generate/mod.rs

@@ -1,4 +1,5 @@
 use std::fs;
+use std::io::Write;
 use std::path::{Path, PathBuf};
 
 use clap::Arg;
@@ -66,11 +67,25 @@ pub fn cli() -> clap::Command {
             Arg::new("skip_clippy")
                 .long("skip_clippy")
                 .short('s')
+                .short('S')
                 .action(SetTrue)
                 .env("SPACETIME_SKIP_CLIPPY")
                 .value_parser(clap::builder::FalseyValueParser::new())
                 .help("Skips running clippy on the module before generating (intended to speed up local iteration, not recommended for CI)"),
         )
+        .arg(
+            Arg::new("delete_files")
+                .long("delete-files")
+                .action(SetTrue)
+                .help("Delete outdated generated files whose definitions have been removed from the module. Prompts before deleting unless --force is supplied."),
+        )
+        .arg(
+            Arg::new("force")
+                .long("force")
+                .action(SetTrue)
+                .requires("delete_files")
+                .help("delete-files without prompting first. Useful for scripts."),
+        )
         .arg(
             Arg::new("debug")
                 .long("debug")
@@ -89,6 +104,8 @@ pub fn exec(args: &clap::ArgMatches) -> anyhow::Result<()> {
     let namespace = args.get_one::<String>("namespace").unwrap();
     let skip_clippy = args.get_flag("skip_clippy");
     let build_debug = args.get_flag("debug");
+    let delete_files = args.get_flag("delete_files");
+    let force = args.get_flag("force");
 
     let wasm_file = match wasm_file {
         Some(x) => x,
@@ -101,7 +118,7 @@ pub fn exec(args: &clap::ArgMatches) -> anyhow::Result<()> {
 Failed to compile module {:?}. See cargo errors above for more details.",
                     e,
                     project_path,
-                ))
+                ));
             }
         },
     };
@@ -120,7 +137,54 @@ Failed to compile module {:?}. See cargo errors above for more details.",
         fs::write(path, code)?;
     }
 
-    format_files(paths, lang)?;
+    format_files(paths.clone(), lang)?;
+
+    if delete_files {
+        let mut files_to_delete = vec![];
+        for entry in fs::read_dir(out_dir)? {
+            let entry = entry?;
+            let path = entry.path();
+            if path.is_file() {
+                if let Ok(contents) = fs::read_to_string(&path) {
+                    if !contents.starts_with("// THIS FILE IS AUTOMATICALLY GENERATED BY SPACETIMEDB.") {
+                        continue;
+                    }
+                }
+
+                if paths
+                    .iter()
+                    .any(|x| x.file_name().unwrap() == path.file_name().unwrap())
+                {
+                    continue;
+                }
+                files_to_delete.push(path);
+            }
+        }
+        if !files_to_delete.is_empty() {
+            let mut input = "y".to_string();
+            println!("The following files were not generated by this command and will be deleted:");
+            for path in &files_to_delete {
+                println!("  {}", path.to_str().unwrap());
+            }
+
+            if !force {
+                print!("Are you sure you want to delete these files? [y/N] ");
+                std::io::stdout().flush()?;
+                std::io::stdin().read_line(&mut input)?;
+            } else {
+                println!("Force flag present, deleting files without prompting.");
+            }
+
+            if input.trim().to_lowercase() == "y" || input.trim().to_lowercase() == "yes" {
+                for path in files_to_delete {
+                    fs::remove_file(path)?;
+                }
+                println!("Files deleted successfully.");
+            } else {
+                println!("Files not deleted.");
+            }
+        }
+    }
 
     println!("Generate finished successfully.");
     Ok(())
@@ -133,6 +197,7 @@ pub enum Language {
     Python,
     Rust,
 }
+
 impl clap::ValueEnum for Language {
     fn value_variants<'a>() -> &'a [Self] {
         &[Self::Csharp, Self::TypeScript, Self::Python, Self::Rust]
@@ -407,6 +472,7 @@ struct WasmCtx {
     mem: Option<Memory>,
     buffers: slab::Slab<Vec<u8>>,
 }
+
 impl WasmCtx {
     fn mem(&self) -> Memory {
         self.mem.unwrap()
@@ -426,6 +492,7 @@ impl WasmCtx {
 struct Memory {
     mem: wasmtime::Memory,
 }
+
 impl Memory {
     fn deref_slice<'a>(&self, store: &'a impl AsContext, offset: u32, len: u32) -> Option<&'a [u8]> {
         self.mem