fix: implement dynamic template loader for include functionality

Cargo.toml

@@ -10,7 +10,7 @@ keywords = ["template", "minijinja", "cli", "environment", "variables"]
 categories = ["command-line-utilities", "template-engine"]
 
 [dependencies]
-minijinja = { version = "2", features = ["builtins"] }
+minijinja = { version = "2", features = ["builtins", "loader"] }
 clap = { version = "4", features = ["derive"] }
 serde = { version = "1", features = ["derive"] }
 regex = "1"

README.md

@@ -7,7 +7,7 @@
 [![Docker](https://img.shields.io/badge/docker-ghcr.io-blue)](https://github.com/bordeux/tmpltool/pkgs/container/tmpltool)
 [![License](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE)
 
-A fast and simple command-line template rendering tool using [Tera](https://keats.github.io/tera/) templates with environment variables.
+A fast and simple command-line template rendering tool using [MiniJinja](https://github.com/mitsuhiko/minijinja) templates with environment variables.
 
 ## Table of Contents
 
@@ -71,7 +71,7 @@ tmpltool greeting.tmpl
 - **Validation**: Validate emails, URLs, IPs, UUIDs, regex matching
 - **Security**: Built-in protections with optional `--trust` mode
 - **Flexible I/O**: File or stdin input, file or stdout output
-- **Full Tera Syntax**: Conditionals, loops, filters, and more
+- **Full Jinja2 Syntax**: Conditionals, loops, filters, and more
 - **Single Binary**: No runtime dependencies
 - **Docker Support**: Multi-arch images available
 
@@ -285,7 +285,7 @@ tmpltool build-report.tmpl
 
 ## Template Syntax
 
-tmpltool uses the [Tera](https://keats.github.io/tera/) template engine. For complete documentation, visit: https://keats.github.io/tera/docs/
+tmpltool uses the [MiniJinja](https://github.com/mitsuhiko/minijinja) template engine, which is compatible with Python's Jinja2. For complete documentation, visit: https://docs.rs/minijinja/
 
 ### Variables
 
@@ -1346,4 +1346,6 @@ This project is licensed under the MIT License - see the [LICENSE](LICENSE) file
 
 For more examples, see the [examples/](examples/) directory and [examples/README.md](examples/README.md).
 
-For complete Tera syntax documentation, visit: https://keats.github.io/tera/docs/
+For complete MiniJinja/Jinja2 syntax documentation, visit:
+- MiniJinja Docs: https://docs.rs/minijinja/
+- Jinja2 Template Designer: https://jinja.palletsprojects.com/templates/

examples/test-include.tmpl

@@ -0,0 +1,6 @@
+Testing relative path resolution:
+
+File content from ./basic.tmpl parsed:
+{% include "./basic.tmpl" %}
+
+End of test.

src/renderer.rs

@@ -85,6 +85,49 @@ fn render(
     // Set strict undefined behavior - fail on undefined variables (like Tera)
     env.set_undefined_behavior(minijinja::UndefinedBehavior::Strict);
 
+    // Clone template_context for use in the loader closure
+    let loader_context = template_context.clone();
+
+    // Set up lazy template loader for includes
+    env.set_loader(move |name: &str| -> Result<Option<String>, minijinja::Error> {
+        // Validate path security unless in trust mode
+        if !loader_context.is_trust_mode() {
+            if name.starts_with('/') {
+                return Err(minijinja::Error::new(
+                    minijinja::ErrorKind::InvalidOperation,
+                    format!(
+                        "Security: Absolute paths are not allowed: {}. Use --trust to bypass this restriction.",
+                        name
+                    ),
+                ));
+            }
+            if name.contains("..") {
+                return Err(minijinja::Error::new(
+                    minijinja::ErrorKind::InvalidOperation,
+                    format!(
+                        "Security: Parent directory (..) traversal is not allowed: {}. Use --trust to bypass this restriction.",
+                        name
+                    ),
+                ));
+            }
+        }
+
+        // Resolve the template path relative to the base directory
+        let resolved_path = loader_context.resolve_path(name);
+
+        // Read the template file
+        match fs::read_to_string(&resolved_path) {
+            Ok(content) => Ok(Some(content)),
+            Err(e) => {
+                // Return a helpful error message
+                Err(minijinja::Error::new(
+                    minijinja::ErrorKind::TemplateNotFound,
+                    format!("Failed to load template '{}': {}", resolved_path.display(), e),
+                ))
+            }
+        }
+    });
+
     // Register all custom functions
     functions::register_all(&mut env, template_context);
 

tests/fixtures/expected/include_base.txt

@@ -0,0 +1,4 @@
+Header: Default Header
+Content from partial template.
+User: guest
+Footer: Done

tests/fixtures/expected/include_nested.txt

@@ -0,0 +1,5 @@
+Main template start
+Level 1 start
+Level 2: nested value
+Level 1 end
+Main template end

tests/fixtures/templates/include_base.tmpl

@@ -0,0 +1,3 @@
+Header: {{ get_env(name="HEADER", default="Default Header") }}
+{% include "./include_partial.tmpl" %}
+Footer: Done

tests/fixtures/templates/include_nested_level1.tmpl

@@ -0,0 +1,3 @@
+Level 1 start
+{% include "./include_nested_level2.tmpl" %}
+Level 1 end

tests/fixtures/templates/include_nested_level2.tmpl

@@ -0,0 +1 @@
+Level 2: nested value

tests/fixtures/templates/include_nested_main.tmpl

@@ -0,0 +1,3 @@
+Main template start
+{% include "./include_nested_level1.tmpl" %}
+Main template end

tests/fixtures/templates/include_partial.tmpl

@@ -0,0 +1,2 @@
+Content from partial template.
+User: guest