fix: 🚑 fixed windows cli bug

Switched to renaming `pkg/` to `dist/pkg/` with `fs` rather than `rm`.

Author: arctic-hen7

packages/perseus-cli/src/build.rs

@@ -2,6 +2,7 @@ use crate::cmd::run_stage;
 use crate::errors::*;
 use console::{style, Emoji};
 use std::path::PathBuf;
+use std::fs;
 
 // Emojis for stages
 static GENERATING: Emoji<'_, '_> = Emoji("🔨", "");
@@ -36,19 +37,25 @@ pub fn build_internal(dir: PathBuf, num_steps: u8) -> Result<i32> {
     )?);
     // WASM building
     handle_exit_code!(run_stage(
-        vec![
-            "wasm-pack build --target web",
-            // Move the `pkg/` directory into `dist/pkg/`
-            "rm -rf dist/pkg",
-            "mv pkg/ dist/",
-        ],
+        vec!["wasm-pack build --target web"],
         &target,
         format!(
             "{} {} Building your app to WASM",
             style(format!("[2/{}]", num_steps)).bold().dim(),
             BUILDING
         )
     )?);
+    // Move the `pkg/` directory into `dist/pkg/`
+    let pkg_dir = target.join("dist/pkg");
+    if pkg_dir.exists() {
+        if let Err(err) = fs::remove_dir_all(&pkg_dir) {
+            bail!(ErrorKind::MovePkgDirFailed(err.to_string()));
+        }
+    }
+    // The `fs::rename()` function will fail on Windows if the destination already exists, so this should work (we've just deleted it as per https://github.com/rust-lang/rust/issues/31301#issuecomment-177117325)
+    if let Err(err) = fs::rename(target.join("pkg"), target.join("dist/pkg")) {
+        bail!(ErrorKind::MovePkgDirFailed(err.to_string()));
+    }
     // JS bundle generation
     handle_exit_code!(run_stage(
         vec!["rollup main.js --format iife --file dist/pkg/bundle.js"],

packages/perseus-cli/src/errors.rs

@@ -69,6 +69,11 @@ error_chain! {
             description("port in PORT environment variable couldn't be parsed as number")
             display("Couldn't parse 'PORT' environment variable as a number, please check that you've provided the correct value. Error was: '{}'.", err)
         }
+        /// For when moving the `pkg/` directory to `dist/pkg/` fails.
+        MovePkgDirFailed(err: String) {
+            description("couldn't move `pkg/` to `dist/pkg/`")
+            display("Couldn't move `.perseus/pkg/` to `.perseus/dist/pkg`. Error was: '{}'.", err)
+        }
     }
 }