Improve environment variable handling and user feedback

Fix environment variable export format to properly handle empty
variables by using parameter expansion syntax. This prevents issues
when PATH or similar variables are unset initially.

Add progress indicators for git cloning operations to provide better
user feedback during long-running fetch operations. The spinner
shows activity while maintaining clean output in non-interactive
environments.

Enhance archive handling to support direct file copying when output
filename is specified, avoiding unnecessary extraction for single
files. Add caching awareness by logging when cached downloads are
reused instead of re-downloading.

Standardize progress message formatting across all operations for
consistency, removing trailing periods and adjusting verb tenses
to match established patterns.

Author: PatWie

src/cli.rs

@@ -628,7 +628,7 @@ fn handle_env_command(sprout_path: &str, command: EnvCommand) -> Result<()> {
 
                             for (var, path) in &package.exports {
                                 let full_path = dist_path.join(path.trim_start_matches('/'));
-                                println!("export {}=\"{}:${{{}}}\"", var, full_path.display(), var);
+                                println!("export {}=\"${{{}:+${{{}}}:}}{}\"", var, var, var, full_path.display());
                             }
                         }
                     }

src/core/deps.rs

@@ -392,7 +392,7 @@ pub fn build_package(
 
     if let Some(pb) = pb {
         pb.finish_and_clear();
-        println!("  ✓ Built {}.", module_id);
+        println!("  ✓ Built {}", module_id);
     }
 
     // Update lockfile
@@ -437,6 +437,8 @@ pub fn get_dist_path(sprout_path: &str, package: &ModuleBlock) -> PathBuf {
 
 fn fetch_git(sprout_path: &str, package: &ModuleBlock, git: &crate::ast::GitSpec) -> Result<()> {
     use std::process::Command;
+    use indicatif::{ProgressBar, ProgressStyle};
+    use std::time::Duration;
 
     let source_path = get_source_path(sprout_path, package);
 
@@ -455,7 +457,18 @@ fn fetch_git(sprout_path: &str, package: &ModuleBlock, git: &crate::ast::GitSpec
     let log_filename = format!("{}-fetch-{}.log", package.id(), timestamp);
     let log_path = logs_dir.join(&log_filename);
 
-    info!("Cloning git repository: {} -> {}", git.url, source_path.display());
+    let pb = if atty::is(atty::Stream::Stderr) {
+        let pb = ProgressBar::new_spinner();
+        pb.set_style(ProgressStyle::default_spinner()
+            .template("  {spinner} {msg}")?);
+        pb.set_message(format!("Cloning {}", package.id()));
+        pb.enable_steady_tick(Duration::from_millis(100));
+        Some(pb)
+    } else {
+        info!("Cloning git repository: {} -> {}", git.url, source_path.display());
+        None
+    };
+
     info!("Fetch log: {}", log_path.display());
 
     // Log git clone command
@@ -490,6 +503,13 @@ fn fetch_git(sprout_path: &str, package: &ModuleBlock, git: &crate::ast::GitSpec
         .stderr(fs::OpenOptions::new().append(true).open(&log_path)?)
         .status()?;
 
+    if let Some(pb) = pb {
+        pb.finish_and_clear();
+        if status.success() {
+            println!("  ✓ Cloned {}", package.id());
+        }
+    }
+
     if !status.success() {
         return Err(anyhow!(
             "git clone failed with exit code: {:?}\nLog saved to: {}",
@@ -516,6 +536,8 @@ fn fetch_archive(sprout_path: &str, package: &ModuleBlock, archive: &crate::ast:
 
     if !cache_path.exists() {
         download_file(&archive.url, &cache_path, original_filename)?;
+    } else {
+        info!("Using cached {}", original_filename);
     }
 
     // Compute SHA256 if not present in manifest
@@ -560,8 +582,18 @@ fn fetch_archive(sprout_path: &str, package: &ModuleBlock, archive: &crate::ast:
         .map(|s| s.as_str())
         .unwrap_or(original_filename);
 
-    info!("Extracting {} -> {}", original_filename, source_path.display());
-    extract_archive_with_output(&cache_path, &source_path, original_filename, output_filename)?;
+    // If output is specified, skip extraction (just copy the file)
+    let skip_extract = package.fetch.as_ref()
+        .and_then(|f| f.output.as_ref())
+        .is_some();
+
+    if skip_extract {
+        info!("Copying {} -> {}", original_filename, source_path.display());
+        copy_file_with_progress(&cache_path, &source_path, original_filename, output_filename)?;
+    } else {
+        info!("Extracting {} -> {}", original_filename, source_path.display());
+        extract_archive_with_output(&cache_path, &source_path, original_filename, output_filename)?;
+    }
     Ok(())
 }
 
@@ -577,7 +609,7 @@ fn download_file(url: &str, dest: &Path, filename: &str) -> Result<()> {
         pb.set_style(ProgressStyle::default_bar()
             .template("  {msg} [{bar:40}] {bytes}/{total_bytes} ({eta})")?
             .progress_chars("=>-"));
-        pb.set_message(format!("Download {}", filename));
+        pb.set_message(format!("Downloading {}", filename));
         Some(pb)
     } else {
         info!("Downloading {}", filename);
@@ -599,7 +631,7 @@ fn download_file(url: &str, dest: &Path, filename: &str) -> Result<()> {
     }
 
     if let Some(pb) = pb {
-        pb.finish_with_message(format!("✓ Download {}", filename));
+        pb.finish_with_message(format!("✓ Downloaded {}", filename));
     } else {
         info!("Downloaded {}", filename);
     }
@@ -627,19 +659,54 @@ fn compute_file_sha256(path: &Path) -> Result<String> {
     Ok(format!("{:x}", hasher.finalize()))
 }
 
+fn copy_file_with_progress(cache_path: &Path, dest_dir: &Path, filename: &str, output_name: &str) -> Result<()> {
+    use indicatif::{ProgressBar, ProgressStyle};
+    use std::time::Duration;
+
+    let pb = if atty::is(atty::Stream::Stderr) {
+        let pb = ProgressBar::new_spinner();
+        pb.set_style(ProgressStyle::default_spinner()
+            .template("  {spinner} {msg}")?);
+        pb.set_message(format!("Copying {}", filename));
+        pb.enable_steady_tick(Duration::from_millis(100));
+        Some(pb)
+    } else {
+        info!("Copying {}", filename);
+        None
+    };
+
+    let output_path = dest_dir.join(output_name);
+    std::fs::copy(cache_path, &output_path)?;
+
+    if let Some(pb) = pb {
+        pb.finish_and_clear();
+        println!("  ✓ Copied {}", filename);
+    } else {
+        info!("Copied {}", filename);
+    }
+    Ok(())
+}
+
 fn extract_archive_with_output(cache_path: &Path, dest: &Path, filename: &str, output_name: &str) -> Result<()> {
     use indicatif::{ProgressBar, ProgressStyle};
     use std::time::Duration;
 
+    let is_archive = filename.ends_with(".tar.gz") || filename.ends_with(".tgz") 
+        || filename.ends_with(".tar.xz") || filename.ends_with(".zip")
+        || filename.ends_with(".gz") || filename.ends_with(".xz");
+
+    let action = if is_archive { "Extracting" } else { "Copying" };
+    let action_past = if is_archive { "Extracted" } else { "Copied" };
+
     let pb = if atty::is(atty::Stream::Stderr) {
         let pb = ProgressBar::new_spinner();
         pb.set_style(ProgressStyle::default_spinner()
             .template("  {spinner} {msg}")?);
-        pb.set_message(format!("Extract {}", filename));
+        pb.set_message(format!("{} {}", action, filename));
         pb.enable_steady_tick(Duration::from_millis(100));
         Some(pb)
     } else {
-        info!("Extracting {}", filename);
+        info!("{} {}", action, filename);
         None
     };
 
@@ -677,9 +744,9 @@ fn extract_archive_with_output(cache_path: &Path, dest: &Path, filename: &str, o
 
     if let Some(pb) = pb {
         pb.finish_and_clear();
-        println!("  ✓ Extracted {}.", filename);
+        println!("  ✓ {} {}", action_past, filename);
     } else {
-        info!("Extracted {}", filename);
+        info!("{} {}", action_past, filename);
     }
     Ok(())
 }