optional Webhook column on the stacks list with a git stack's webhook id and copy-URL button

src/lib/server/dockhand-override-file.ts

@@ -0,0 +1,17 @@
+/**
+ * Build the `.env.dockhand` override-file contents for a git stack.
+ *
+ * A git stack's compose commonly references `env_file: [.env.dockhand]` (the
+ * documented way to consume Dockhand-managed non-secret vars). The file must exist
+ * for `docker compose up` to parse - even when there are ZERO panel vars, in which
+ * case it is just the header line (#1336). Pure: no FS, no DB, so both the local
+ * (writeFileSync) and Hawser (in-memory stackFiles) deploy paths share one source of
+ * truth and are unit-testable.
+ */
+
+const HEADER = '# Auto-generated by Dockhand. Do not edit - changes will be overwritten on next deploy.\n';
+
+export function buildDockhandOverrideFile(envVars: Record<string, string>): string {
+	const lines = Object.entries(envVars).map(([k, v]) => `${k}=${v}`);
+	return HEADER + lines.join('\n') + (lines.length ? '\n' : '');
+}

src/lib/server/stacks.ts

@@ -51,6 +51,7 @@ import { cleanPem } from '$lib/utils/pem';
 import { rewriteComposeVolumePaths, getHostDataDir } from './host-path';
 import { getOrderValue } from './container-labels';
 import { pendingRowsToClear } from './pending-updates-core';
+import { buildDockhandOverrideFile } from './dockhand-override-file';
 
 // =============================================================================
 // TYPES
@@ -1247,17 +1248,17 @@ async function executeLocalCompose(
 		args.push('--env-file', customEnvPath);
 	}
 
-	// For git stacks: write non-secret overrides to .env.dockhand and add as second --env-file
+	// For git stacks: write non-secret overrides to .env.dockhand and add as second --env-file.
 	// Docker Compose applies env files in order, so later files override earlier ones.
 	// This lets the repo's .env provide defaults while our overrides take precedence.
 	// Secrets are still injected via shell env only (never written to disk).
-	// Only written when useOverrideFile is true (git stacks). Internal/adopted stacks
-	// already have their non-secrets in the .env file written by the UI.
+	// ONLY when there ARE overrides: any --env-file on the CLI suppresses Compose's
+	// auto-discovery of the adjacent default .env, so writing one for a zero-var stack
+	// would blank a subdir compose's own .env interpolation (#1136). Internal/adopted
+	// stacks already have their non-secrets in the .env file written by the UI.
 	if (useOverrideFile && envVars && Object.keys(envVars).length > 0) {
 		const overrideEnvPath = join(composeFileDir, '.env.dockhand');
-		const header = '# Auto-generated by Dockhand. Do not edit - changes will be overwritten on next deploy.\n';
-		const lines = Object.entries(envVars).map(([k, v]) => `${k}=${v}`);
-		writeFileSync(overrideEnvPath, header + lines.join('\n') + '\n');
+		writeFileSync(overrideEnvPath, buildDockhandOverrideFile(envVars));
 		args.push('--env-file', overrideEnvPath);
 	}
 
@@ -1705,13 +1706,12 @@ async function executeComposeCommand(
 				}
 			}
 
-			// For git stacks: generate .env.dockhand with non-secret DB overrides
-			// This mirrors executeLocalCompose behavior (lines 1017-1023).
-			// envVars contains only the DB overrides (not merged repo .env values from hawserEnvVars).
+			// For git stacks: generate .env.dockhand with non-secret DB overrides.
+			// ONLY when there ARE overrides: the agent adds it as --env-file, which
+			// suppresses Compose's adjacent-.env auto-discovery, so an empty file would
+			// blank a subdir compose's own .env interpolation (#1136).
 			if (useOverrideFile && envVars && Object.keys(envVars).length > 0) {
-				const header = '# Auto-generated by Dockhand. Do not edit - changes will be overwritten on next deploy.\n';
-				const lines = Object.entries(envVars).map(([k, v]) => `${k}=${v}`);
-				hawserStackFiles = { ...(hawserStackFiles || {}), '.env.dockhand': header + lines.join('\n') + '\n' };
+				hawserStackFiles = { ...(hawserStackFiles || {}), '.env.dockhand': buildDockhandOverrideFile(envVars) };
 				console.log(`[Stack:${stackName}] Including .env.dockhand override file for Hawser (${Object.keys(envVars).length} vars)`);
 			}