non-zero exit when appropriate

build.zig.zon

@@ -14,8 +14,8 @@
             .hash = "httpz-0.0.0-PNVzrBtMBwAPcQx3mNEgat3Xbsynw-eIC9SmOX5M9XtP",
         },
         .zfin = .{
-            .url = "git+https://git.lerch.org/lobo/zfin#5052492ffd49ebdc11b209da1b86bbaf7d365e5e",
+            .url = "git+https://git.lerch.org/lobo/zfin#ecadfb492d8730c3226c738b6cb63e688d7f89dc",
-            .hash = "zfin-0.0.0-J-B21ryaDACsjkyET8s_NhF0W745-Qoc_fj9VM8Z-Ngx",
+            .hash = "zfin-0.0.0-J-B21tqwDACaht3HgLXCYDXJsyZsMwzncEKeX2JYiiJG",
         },
     },
 }

src/main.zig

@@ -175,8 +175,8 @@ fn handleReturns(app: *App, req: *httpz.Request, res: *httpz.Response) !void {
     const vol_term: ?u8 = if (v10y != null) 10 else if (v5y != null) 5 else if (v3y != null) 3 else if (v1y != null) 1 else null;
 
     // Total returns: adj_close is the primary source (accounts for splits + dividends).
-    // Dividend-reinvestment is only used as fallback when adj_close returns null
+    // Dividend-reinvestment only fills gaps where adj_close returns null
-    // (e.g. candle history too short for stable-NAV funds like money markets).
+    // (e.g. stable-NAV funds with short candle history).
     var t1y: ?f64 = p1y;
     var t3y: ?f64 = p3y;
     var t5y: ?f64 = p5y;
@@ -485,6 +485,14 @@ fn refresh(allocator: std.mem.Allocator) !void {
         } else |err| {
             try stdout.print("candles FAILED ({s})", .{@errorName(err)});
             sym_ok = false;
+            if (err == zfin.DataError.TransientError or err == zfin.DataError.AuthError) {
+                const reason = if (err == zfin.DataError.AuthError) "auth failure" else "transient provider failure";
+                try stdout.print("\n", .{});
+                try stdout.print("\nStopping refresh: {s}\n", .{reason});
+                try stdout.print("Refresh aborted: {d} ok, {d} failed\n", .{ success_count, fail_count + 1 });
+                try stdout.flush();
+                return error.RefreshFailed;
+            }
         }
 
         // Dividends
@@ -515,6 +523,8 @@ fn refresh(allocator: std.mem.Allocator) !void {
 
     try stdout.print("\nRefresh complete: {d} ok, {d} failed\n", .{ success_count, fail_count });
     try stdout.flush();
+
+    if (fail_count > 0) return error.RefreshFailed;
 }
 
 // ── Main ─────────────────────────────────────────────────────