fix(iac): render preDeploy as a first-class field in migrate and pull (#1167)

Config as Code migrations were emitting the pre-deploy command as a
comment ('// preDeployCommand from CaC: ...'), silently dropping working
migration config even though the IaC SDK and apply path fully support
the field. config pull buried it in the raw deploy block for the same
reason. Emit 'preDeploy:' as a real field in both, unwrapping the
single-command array to a bare string.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: codyde

src/commands/config/migrate.rs

@@ -613,6 +613,16 @@ fn emit_service_fields(cac: &CacFile) -> Vec<String> {
     } else if let Some(region) = &cac.deploy.region {
         fields.push(format!("    replicas: {{ {}: 1 }},", js_string(region)));
     }
+    if let Some(pre) = &cac.deploy.pre_deploy_command {
+        let rendered = match pre {
+            JsonValue::Array(items) if items.len() == 1 && items[0].is_string() => {
+                js_string(items[0].as_str().unwrap_or_default())
+            }
+            JsonValue::String(cmd) => js_string(cmd),
+            other => json_to_ts(other),
+        };
+        fields.push(format!("    preDeploy: {rendered},"));
+    }
     if let Some(dockerfile) = &cac.build.dockerfile_path {
         fields.push(format!(
             "    // dockerfilePath from CaC: {}",
@@ -625,12 +635,6 @@ fn emit_service_fields(cac: &CacFile) -> Vec<String> {
     if let Some(cron) = &cac.deploy.cron_schedule {
         fields.push(format!("    // cronSchedule from CaC: {}", js_string(cron)));
     }
-    if let Some(pre) = &cac.deploy.pre_deploy_command {
-        fields.push(format!(
-            "    // preDeployCommand from CaC: {}",
-            json_to_ts(pre)
-        ));
-    }
     if let Some(watch) = &cac.build.watch_patterns {
         let arr = watch
             .iter()
@@ -847,6 +851,22 @@ mod tests {
         assert!(go.contains("const Partial = \"api\""));
     }
 
+    #[test]
+    fn emits_pre_deploy_as_a_real_field() {
+        let cac = CacFile {
+            deploy: CacDeploy {
+                start_command: Some("node index.js".into()),
+                pre_deploy_command: Some(serde_json::json!(["npx prisma migrate deploy"])),
+                ..Default::default()
+            },
+            ..Default::default()
+        };
+        let services = [svc("api", cac)];
+        let out = emit_railway_ts("api", &services, true);
+        assert!(out.contains("preDeploy: \"npx prisma migrate deploy\""));
+        assert!(!out.contains("// preDeployCommand from CaC"));
+    }
+
     #[test]
     fn merges_multiple_services_without_a_partial() {
         let web = svc(

src/commands/config/mod.rs

@@ -1307,6 +1307,18 @@ fn render_deploy(
     if let Some(timeout) = remaining.remove("healthcheckTimeout") {
         lines.push(lang.config_field("healthcheckTimeout", &code_value(&timeout, lang)));
     }
+    if let Some(pre) = remaining.remove("preDeployCommand") {
+        if !pre.is_null() {
+            let rendered = match &pre {
+                serde_json::Value::Array(items) if items.len() == 1 && items[0].is_string() => {
+                    format!("{:?}", items[0].as_str().unwrap_or_default())
+                }
+                serde_json::Value::String(command) => format!("{:?}", command),
+                other => code_value(other, lang),
+            };
+            lines.push(lang.config_field("preDeploy", &rendered));
+        }
+    }
     if let Some(regions) = remaining.remove("multiRegionConfig") {
         lines.push(lang.config_field("replicas", &render_replicas(&regions, lang)));
     }