From 8a6274ef6af4516e0db1bd74d8a89cca12b86141 Mon Sep 17 00:00:00 2001
From: Chili Palmer <hugoms@me.com>
Date: Tue, 21 Jul 2026 23:18:12 +0200
Subject: [PATCH] Normalize template and script slug changes.

---
 README.md                                  |   2 +-
 crates/bds-core/src/engine/script.rs       | 162 +++++++++++++++++++--
 crates/bds-core/src/engine/template.rs     | 150 ++++++++++++++++---
 crates/bds-core/src/scripting/core_host.rs |   1 +
 crates/bds-server/src/tui.rs               |   1 +
 crates/bds-ui/src/app.rs                   |  25 +++-
 specs/script.allium                        |   6 +
 specs/template.allium                      |   6 +
 8 files changed, 312 insertions(+), 41 deletions(-)

diff --git a/README.md b/README.md
index 96317b6..b62af9b 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ The project is under active development. Core blogging workflows are broadly ava
 - Post and translation authoring with change-aware draft/published/archive lifecycle, file-backed change discard, canonical draft reopening after manual translation edits, non-disruptive automatic translation, desktop archive/unarchive actions, in-place published-frontmatter updates, metadata, tags, categories, live link/backlink graphs, media, and batch gallery-image import.
 - Media import, thumbnails, metadata translations, filters, validation, post assignment, and sequential drag-and-drop insertion into post editors.
 - WordPress WXR migration with saved analyses, HTML-to-Markdown and shortcode conversion, conflict/taxonomy review, recoverable 500-item execution batches, media-parent linking, progress reporting, and optional AI-assisted taxonomy mapping.
-- Post, Liquid template, and Lua script editing with dedicated syntax highlighting, explicit syntax-check feedback, reference-safe template slug changes, and publish-time enforcement of the bDS2 Liquid tag/filter/operator subset, using a custom Ropey/Syntect/Cosmic Text editor and the documented, bDS2-signature-compatible project-scoped [`bds` host API](docs/scripting/API_REFERENCE.md) across utilities, rendered macros, and Blogmark transforms, including airplane-gated Git sync.
+- Post, Liquid template, and Lua script editing with dedicated syntax highlighting, explicit syntax-check feedback, normalized collision-safe template/script slug changes, reference-safe template renames, and publish-time enforcement of the bDS2 Liquid tag/filter/operator subset, using a custom Ropey/Syntect/Cosmic Text editor and the documented, bDS2-signature-compatible project-scoped [`bds` host API](docs/scripting/API_REFERENCE.md) across utilities, rendered macros, and Blogmark transforms, including airplane-gated Git sync.
 - SQLite and filesystem persistence with frontmatter, relationship-safe media sidecars, rebuild, metadata diff/repair, stale post-path cleanup on republish, bDS2-compatible checksums and NFD slug generation, and FTS5 search.
 - Optional on-device multilingual semantic search and similar-post tag suggestions backed by a persistent USearch index, plus always-available partial-name tag autocomplete and duplicate-post review in the desktop workspace.
 - Read-only in-app browsers in the Help menu for the bundled global `DOCUMENTATION.md`, the generated Lua API reference with public types and runnable examples, the [CLI/server/TUI documentation](CLI.md), and the [MCP server documentation](MCP.md), with safe GFM rendering and confirmed external links.
diff --git a/crates/bds-core/src/engine/script.rs b/crates/bds-core/src/engine/script.rs
index cd0c5ff..6b5cade 100644
--- a/crates/bds-core/src/engine/script.rs
+++ b/crates/bds-core/src/engine/script.rs
@@ -8,6 +8,7 @@ use crate::db::queries::script as qs;
 use crate::engine::{EngineError, EngineResult, domain_events};
 use crate::model::{DomainEntity, NotificationAction, Script, ScriptKind, ScriptStatus};
 use crate::util::frontmatter::{ScriptFrontmatter, write_script_file};
+use crate::util::paths::script_file_path;
 use crate::util::{atomic_write_str, ensure_unique, now_unix_ms, slugify};
 
 /// Create a new draft script. Content stored in DB, no file written.
@@ -64,6 +65,7 @@ pub fn create_script(
 )]
 pub fn update_script(
     conn: &Connection,
+    data_dir: &Path,
     script_id: &str,
     project_id: &str,
     title: Option<&str>,
@@ -74,23 +76,28 @@ pub fn update_script(
     content: Option<&str>,
 ) -> EngineResult<Script> {
     let mut script = qs::get_script_by_id(conn, script_id)?;
+    if script.project_id != project_id {
+        return Err(EngineError::NotFound(format!("script {script_id}")));
+    }
+    let original_slug = script.slug.clone();
+    let original_file_path = script.file_path.clone();
 
-    // Slug uniqueness
-    if let Some(new_slug) = slug
-        && new_slug != script.slug
-        && qs::get_script_by_slug(conn, project_id, new_slug).is_ok()
-    {
-        return Err(EngineError::Conflict(format!(
-            "script slug '{new_slug}' already exists"
-        )));
+    if let Some(requested_slug) = slug {
+        let slug = slugify(requested_slug);
+        let slug = if slug.is_empty() {
+            "script".to_string()
+        } else {
+            slug
+        };
+        script.slug = ensure_unique(&slug, |candidate| {
+            qs::get_script_by_slug(conn, project_id, candidate)
+                .is_ok_and(|existing| existing.id != script_id)
+        });
     }
 
     if let Some(t) = title {
         script.title = t.to_string();
     }
-    if let Some(s) = slug {
-        script.slug = s.to_string();
-    }
     if let Some(k) = kind {
         script.kind = k;
     }
@@ -104,6 +111,16 @@ pub fn update_script(
         script.content = Some(c.to_string());
     }
 
+    let slug_changed = script.slug != original_slug;
+    let published_body = if slug_changed && !original_file_path.is_empty() {
+        Some(read_published_script_body(data_dir, &original_file_path))
+    } else {
+        None
+    };
+    if published_body.is_some() {
+        script.file_path = script_file_path(&script.slug);
+    }
+
     // If published, transition back to draft on edit
     if script.status == ScriptStatus::Published {
         script.status = ScriptStatus::Draft;
@@ -112,6 +129,9 @@ pub fn update_script(
     script.version += 1;
     script.updated_at = now_unix_ms();
     qs::update_script(conn, &script)?;
+    if let Some(body) = published_body {
+        rewrite_renamed_script_file(data_dir, &original_file_path, &script, &body)?;
+    }
     emit_script(&script, NotificationAction::Updated);
     Ok(script)
 }
@@ -276,6 +296,46 @@ fn script_kind_to_frontmatter(kind: &ScriptKind) -> String {
     }
 }
 
+fn read_published_script_body(data_dir: &Path, file_path: &str) -> String {
+    fs::read_to_string(data_dir.join(file_path))
+        .ok()
+        .and_then(|file| crate::util::frontmatter::read_script_file(&file).ok())
+        .map(|(_, body)| body)
+        .unwrap_or_default()
+}
+
+fn rewrite_renamed_script_file(
+    data_dir: &Path,
+    original_file_path: &str,
+    script: &Script,
+    body: &str,
+) -> EngineResult<()> {
+    let frontmatter = ScriptFrontmatter {
+        id: script.id.clone(),
+        project_id: Some(script.project_id.clone()),
+        slug: script.slug.clone(),
+        title: script.title.clone(),
+        kind: script_kind_to_frontmatter(&script.kind),
+        entrypoint: script.entrypoint.clone(),
+        enabled: script.enabled,
+        version: script.version,
+        created_at: script.created_at,
+        updated_at: script.updated_at,
+    };
+    atomic_write_str(
+        &data_dir.join(&script.file_path),
+        &write_script_file(&frontmatter, body),
+    )?;
+    if original_file_path != script.file_path {
+        match fs::remove_file(data_dir.join(original_file_path)) {
+            Ok(()) => {}
+            Err(error) if error.kind() == std::io::ErrorKind::NotFound => {}
+            Err(error) => return Err(error.into()),
+        }
+    }
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -339,10 +399,11 @@ mod tests {
 
     #[test]
     fn update_script_bumps_version() {
-        let (db, _dir) = setup();
+        let (db, dir) = setup();
         let s = create_script(db.conn(), "p1", "S", ScriptKind::Macro, "old", None).unwrap();
         let updated = update_script(
             db.conn(),
+            dir.path(),
             &s.id,
             "p1",
             Some("New"),
@@ -358,6 +419,83 @@ mod tests {
         assert_eq!(updated.version, 2);
     }
 
+    #[test]
+    fn update_script_slug_normalizes_and_uniquifies() {
+        let (db, dir) = setup();
+        create_script(db.conn(), "p1", "Alpha", ScriptKind::Utility, "", None).unwrap();
+        let script = create_script(db.conn(), "p1", "Beta", ScriptKind::Utility, "", None).unwrap();
+
+        let updated = update_script(
+            db.conn(),
+            dir.path(),
+            &script.id,
+            "p1",
+            None,
+            Some(" Alpha! "),
+            None,
+            None,
+            None,
+            None,
+        )
+        .unwrap();
+
+        assert_eq!(updated.slug, "alpha-2");
+        assert!(updated.file_path.is_empty());
+
+        let unchanged = update_script(
+            db.conn(),
+            dir.path(),
+            &script.id,
+            "p1",
+            None,
+            Some(" Alpha 2 "),
+            None,
+            None,
+            None,
+            None,
+        )
+        .unwrap();
+        assert_eq!(unchanged.slug, "alpha-2");
+    }
+
+    #[test]
+    fn update_published_script_slug_rewrites_and_renames_file() {
+        let (db, dir) = setup();
+        let script = create_script(
+            db.conn(),
+            "p1",
+            "Published Script",
+            ScriptKind::Utility,
+            "function main()\nend",
+            None,
+        )
+        .unwrap();
+        let published = publish_script(db.conn(), dir.path(), &script.id).unwrap();
+        let old_path = dir.path().join(&published.file_path);
+
+        let updated = update_script(
+            db.conn(),
+            dir.path(),
+            &script.id,
+            "p1",
+            None,
+            Some(" Renamed Script! "),
+            None,
+            None,
+            None,
+            None,
+        )
+        .unwrap();
+
+        assert_eq!(updated.slug, "renamed-script");
+        assert_eq!(updated.file_path, "scripts/renamed-script.lua");
+        assert!(!old_path.exists());
+        let new_file = fs::read_to_string(dir.path().join(&updated.file_path)).unwrap();
+        let (frontmatter, body) = crate::util::frontmatter::read_script_file(&new_file).unwrap();
+        assert_eq!(frontmatter.slug, "renamed-script");
+        assert_eq!(body, "function main()\nend");
+    }
+
     #[test]
     fn save_script_updates_content() {
         let (db, _dir) = setup();
diff --git a/crates/bds-core/src/engine/template.rs b/crates/bds-core/src/engine/template.rs
index 09c6fb2..d687742 100644
--- a/crates/bds-core/src/engine/template.rs
+++ b/crates/bds-core/src/engine/template.rs
@@ -12,6 +12,7 @@ use crate::model::{
     DomainEntity, NotificationAction, Post, Tag, Template, TemplateKind, TemplateStatus,
 };
 use crate::util::frontmatter::{TemplateFrontmatter, write_template_file};
+use crate::util::paths::template_file_path;
 use crate::util::{atomic_write_str, ensure_unique, now_unix_ms, slugify};
 
 const ALLOWED_LIQUID_TAGS: &[&str] = &[
@@ -89,23 +90,24 @@ pub fn update_template(
         return Err(EngineError::NotFound(format!("template {template_id}")));
     }
     let original_slug = tpl.slug.clone();
+    let original_file_path = tpl.file_path.clone();
 
-    // Slug uniqueness check
-    if let Some(new_slug) = slug
-        && new_slug != tpl.slug
-        && qt::get_template_by_slug(conn, project_id, new_slug).is_ok()
-    {
-        return Err(EngineError::Conflict(format!(
-            "template slug '{new_slug}' already exists"
-        )));
+    if let Some(requested_slug) = slug {
+        let slug = slugify(requested_slug);
+        let slug = if slug.is_empty() {
+            "template".to_string()
+        } else {
+            slug
+        };
+        tpl.slug = ensure_unique(&slug, |candidate| {
+            qt::get_template_by_slug(conn, project_id, candidate)
+                .is_ok_and(|existing| existing.id != template_id)
+        });
     }
 
     if let Some(t) = title {
         tpl.title = t.to_string();
     }
-    if let Some(s) = slug {
-        tpl.slug = s.to_string();
-    }
     if let Some(k) = kind {
         tpl.kind = k;
     }
@@ -127,6 +129,14 @@ pub fn update_template(
     }
 
     let slug_changed = tpl.slug != original_slug;
+    let published_body = if slug_changed && !original_file_path.is_empty() {
+        Some(read_published_template_body(data_dir, &original_file_path))
+    } else {
+        None
+    };
+    if published_body.is_some() {
+        tpl.file_path = template_file_path(&tpl.slug);
+    }
     tpl.version += 1;
     tpl.updated_at = now_unix_ms();
     conn.begin_savepoint()?;
@@ -155,6 +165,16 @@ pub fn update_template(
         }
     };
 
+    for post in &affected_posts {
+        crate::engine::post::rewrite_published_post(conn, data_dir, &post.id)?;
+    }
+    if slug_changed {
+        crate::engine::tag::rewrite_tags_json(conn, data_dir, &tpl.project_id)?;
+    }
+    if let Some(body) = published_body {
+        rewrite_renamed_template_file(data_dir, &original_file_path, &tpl, &body)?;
+    }
+
     emit_template(&tpl, NotificationAction::Updated);
     for post in &affected_posts {
         domain_events::entity_changed(
@@ -172,13 +192,6 @@ pub fn update_template(
             NotificationAction::Updated,
         );
     }
-
-    for post in &affected_posts {
-        crate::engine::post::rewrite_published_post(conn, data_dir, &post.id)?;
-    }
-    if slug_changed {
-        crate::engine::tag::rewrite_tags_json(conn, data_dir, &tpl.project_id)?;
-    }
     Ok(tpl)
 }
 
@@ -361,6 +374,45 @@ fn template_kind_to_frontmatter(kind: &TemplateKind) -> String {
     }
 }
 
+fn read_published_template_body(data_dir: &Path, file_path: &str) -> String {
+    fs::read_to_string(data_dir.join(file_path))
+        .ok()
+        .and_then(|file| crate::util::frontmatter::read_template_file(&file).ok())
+        .map(|(_, body)| body)
+        .unwrap_or_default()
+}
+
+fn rewrite_renamed_template_file(
+    data_dir: &Path,
+    original_file_path: &str,
+    template: &Template,
+    body: &str,
+) -> EngineResult<()> {
+    let frontmatter = TemplateFrontmatter {
+        id: template.id.clone(),
+        project_id: Some(template.project_id.clone()),
+        slug: template.slug.clone(),
+        title: template.title.clone(),
+        kind: template_kind_to_frontmatter(&template.kind),
+        enabled: template.enabled,
+        version: template.version,
+        created_at: template.created_at,
+        updated_at: template.updated_at,
+    };
+    atomic_write_str(
+        &data_dir.join(&template.file_path),
+        &write_template_file(&frontmatter, body),
+    )?;
+    if original_file_path != template.file_path {
+        match fs::remove_file(data_dir.join(original_file_path)) {
+            Ok(()) => {}
+            Err(error) if error.kind() == std::io::ErrorKind::NotFound => {}
+            Err(error) => return Err(error.into()),
+        }
+    }
+    Ok(())
+}
+
 fn validate_liquid_subset(content: &str) -> Result<(), String> {
     let mut cursor = 0;
     while let Some((offset, is_tag)) = next_liquid_markup(&content[cursor..]) {
@@ -689,22 +741,74 @@ mod tests {
     }
 
     #[test]
-    fn update_template_slug_conflict() {
+    fn update_template_slug_normalizes_and_uniquifies() {
         let (db, dir) = setup();
         create_template(db.conn(), "p1", "Alpha", TemplateKind::Post, "").unwrap();
         let t2 = create_template(db.conn(), "p1", "Beta", TemplateKind::Post, "").unwrap();
-        let result = update_template(
+        let updated = update_template(
             db.conn(),
             dir.path(),
             &t2.id,
             "p1",
             None,
-            Some("alpha"),
+            Some(" Alpha! "),
             None,
             None,
             None,
-        );
-        assert!(result.is_err());
+        )
+        .unwrap();
+        assert_eq!(updated.slug, "alpha-2");
+        assert!(updated.file_path.is_empty());
+
+        let unchanged = update_template(
+            db.conn(),
+            dir.path(),
+            &t2.id,
+            "p1",
+            None,
+            Some(" Alpha 2 "),
+            None,
+            None,
+            None,
+        )
+        .unwrap();
+        assert_eq!(unchanged.slug, "alpha-2");
+    }
+
+    #[test]
+    fn update_published_template_slug_rewrites_and_renames_file() {
+        let (db, dir) = setup();
+        let template = create_template(
+            db.conn(),
+            "p1",
+            "Published Template",
+            TemplateKind::Post,
+            "<article>{{ title }}</article>",
+        )
+        .unwrap();
+        let published = publish_template(db.conn(), dir.path(), &template.id).unwrap();
+        let old_path = dir.path().join(&published.file_path);
+
+        let updated = update_template(
+            db.conn(),
+            dir.path(),
+            &template.id,
+            "p1",
+            None,
+            Some(" Renamed Template! "),
+            None,
+            None,
+            None,
+        )
+        .unwrap();
+
+        assert_eq!(updated.slug, "renamed-template");
+        assert_eq!(updated.file_path, "templates/renamed-template.liquid");
+        assert!(!old_path.exists());
+        let new_file = fs::read_to_string(dir.path().join(&updated.file_path)).unwrap();
+        let (frontmatter, body) = crate::util::frontmatter::read_template_file(&new_file).unwrap();
+        assert_eq!(frontmatter.slug, "renamed-template");
+        assert_eq!(body, "<article>{{ title }}</article>");
     }
 
     #[test]
diff --git a/crates/bds-core/src/scripting/core_host.rs b/crates/bds-core/src/scripting/core_host.rs
index 0b48df2..c244ff8 100644
--- a/crates/bds-core/src/scripting/core_host.rs
+++ b/crates/bds-core/src/scripting/core_host.rs
@@ -894,6 +894,7 @@ impl CoreHost {
                 let data = object_arg(args, 1)?;
                 public_script(engine::script::update_script(
                     db.conn(),
+                    &self.data_dir,
                     id,
                     &self.project_id,
                     optional_string_field(data, "title"),
diff --git a/crates/bds-server/src/tui.rs b/crates/bds-server/src/tui.rs
index 384fee8..63ed4eb 100644
--- a/crates/bds-server/src/tui.rs
+++ b/crates/bds-server/src/tui.rs
@@ -1246,6 +1246,7 @@ impl TuiApp {
                 let project_id = self.project_id()?.to_owned();
                 engine::script::update_script(
                     db.conn(),
+                    self.data_dir()?,
                     &id,
                     &project_id,
                     Some(&title),
diff --git a/crates/bds-ui/src/app.rs b/crates/bds-ui/src/app.rs
index 7c27005..4e50c14 100644
--- a/crates/bds-ui/src/app.rs
+++ b/crates/bds-ui/src/app.rs
@@ -818,12 +818,14 @@ fn save_template_editor_state_impl(
 
 fn save_script_editor_state_impl(
     db: &Database,
+    data_dir: &Path,
     project_id: &str,
     state: &ScriptEditorState,
 ) -> Result<Script, String> {
     engine::script::validate_script_syntax(&state.content)?;
     engine::script::update_script(
         db.conn(),
+        data_dir,
         &state.script_id,
         project_id,
         Some(&state.title),
@@ -6660,7 +6662,11 @@ impl BdsApp {
             return Task::none();
         };
 
-        match save_script_editor_state_impl(db, &project.id, state) {
+        let Some(ref data_dir) = self.data_dir else {
+            return Task::none();
+        };
+
+        match save_script_editor_state_impl(db, data_dir, &project.id, state) {
             Ok(script) => {
                 let s = self.script_editors.get_mut(script_id).unwrap();
                 s.is_dirty = false;
@@ -11342,15 +11348,18 @@ mod tests {
             bds_core::db::queries::template::get_template_by_id(db.conn(), &created.id).unwrap();
         let mut editor = TemplateEditorState::from_template(&template_record);
         editor.title = "Updated Template".to_string();
+        editor.slug = " Updated Template! ".to_string();
         editor.content = "<main>{{ title }}</main>".to_string();
 
         let saved_template =
             save_template_editor_state_impl(&db, tmp.path(), &project.id, &editor).unwrap();
         assert_eq!(saved_template.title, "Updated Template");
+        assert_eq!(saved_template.slug, "updated-template");
 
         let saved =
             bds_core::db::queries::template::get_template_by_id(db.conn(), &created.id).unwrap();
         assert_eq!(saved.title, "Updated Template");
+        assert_eq!(saved.slug, "updated-template");
         assert_eq!(saved.content.as_deref(), Some("<main>{{ title }}</main>"));
     }
 
@@ -11385,7 +11394,7 @@ mod tests {
 
     #[test]
     fn script_editor_save_flow_persists_changes() {
-        let (db, project, _tmp) = setup();
+        let (db, project, tmp) = setup();
         let created = script::create_script(
             db.conn(),
             &project.id,
@@ -11400,15 +11409,19 @@ mod tests {
             bds_core::db::queries::script::get_script_by_id(db.conn(), &created.id).unwrap();
         let mut editor = ScriptEditorState::from_script(&script_record);
         editor.title = "Updated Script".to_string();
+        editor.slug = " Updated Script! ".to_string();
         editor.content = "function main()\n  return 'lua'\nend".to_string();
         editor.entrypoint = "main".to_string();
 
-        let saved_script = save_script_editor_state_impl(&db, &project.id, &editor).unwrap();
+        let saved_script =
+            save_script_editor_state_impl(&db, tmp.path(), &project.id, &editor).unwrap();
         assert_eq!(saved_script.title, "Updated Script");
+        assert_eq!(saved_script.slug, "updated-script");
 
         let saved =
             bds_core::db::queries::script::get_script_by_id(db.conn(), &created.id).unwrap();
         assert_eq!(saved.title, "Updated Script");
+        assert_eq!(saved.slug, "updated-script");
         assert_eq!(
             saved.content.as_deref(),
             Some("function main()\n  return 'lua'\nend")
@@ -11417,7 +11430,7 @@ mod tests {
 
     #[test]
     fn script_editor_save_rejects_invalid_content() {
-        let (db, project, _tmp) = setup();
+        let (db, project, tmp) = setup();
         let created = script::create_script(
             db.conn(),
             &project.id,
@@ -11433,7 +11446,8 @@ mod tests {
         let mut editor = ScriptEditorState::from_script(&script_record);
         editor.content = "function main()\n  return 'oops'".to_string();
 
-        let error = save_script_editor_state_impl(&db, &project.id, &editor).unwrap_err();
+        let error =
+            save_script_editor_state_impl(&db, tmp.path(), &project.id, &editor).unwrap_err();
         assert!(error.contains("end") || error.contains("unclosed") || error.contains("missing"));
 
         let saved =
@@ -12775,6 +12789,7 @@ mod tests {
 
         script::update_script(
             app.db.as_ref().unwrap().conn(),
+            tmp.path(),
             &created.id,
             &project.id,
             Some("Remote title"),
diff --git a/specs/script.allium b/specs/script.allium
index ddca144..f80d58f 100644
--- a/specs/script.allium
+++ b/specs/script.allium
@@ -224,6 +224,12 @@ rule CreateScript {
 rule UpdateScript {
     when: UpdateScriptRequested(script, changes)
     ensures: ScriptFieldsUpdated(script, changes)
+    if changes.slug != null:
+        ensures: script.slug = unique_slug(slugify(changes.slug), excluding: script)
+        if script.file_path != "":
+            ensures: script.file_path = format("scripts/{slug}.lua", slug: script.slug)
+            ensures: ScriptFileWritten(script)
+            ensures: PreviousScriptFileDeleted(script)
     ensures: script.updated_at = now
     ensures: script.version = script.version + 1
 }
diff --git a/specs/template.allium b/specs/template.allium
index fad142c..2adbfc0 100644
--- a/specs/template.allium
+++ b/specs/template.allium
@@ -129,6 +129,12 @@ rule CreateAndPublishTemplate {
 rule UpdateTemplate {
     when: UpdateTemplateRequested(template, changes)
     ensures: TemplateFieldsUpdated(template, changes)
+    if changes.slug != null:
+        ensures: template.slug = unique_slug(slugify(changes.slug), excluding: template)
+        if template.file_path != "":
+            ensures: template.file_path = format("templates/{slug}.liquid", slug: template.slug)
+            ensures: TemplateFileWritten(template)
+            ensures: PreviousTemplateFileDeleted(template)
     ensures: template.updated_at = now
     ensures: template.version = template.version + 1
 }