Fix log line assertion error (#1703)

.changeset/fix-empty-string-assertion-error.md

@@ -0,0 +1,13 @@
+---
+ggt: "patch"
+---
+
+Fix the following assertion error from occurring:
+
+```
+An error occurred while communicating with Gadget
+
+'' == true
+
+If you think this is a bug, click here to create an issue on GitHub.
+```

src/services/output/log/format/pretty.ts

@@ -4,7 +4,7 @@ import terminalLink from "terminal-link";
 import { type Environment } from "../../../app/app.js";
 
 import { config } from "../../../config/config.js";
-import { isObject } from "../../../util/is.js";
+import { isNil, isObject } from "../../../util/is.js";
 import { serializeObjectToHTTPQuery } from "../../../util/querystring.js";
 import colors from "../../colors.js";
 import { symbol } from "../../symbols.js";
@@ -47,7 +47,7 @@ const formatValue = (value: string, color: (s: string) => string, indent: number
 
   const buf: string[] = [];
   const firstLine = lines.shift();
-  assert(firstLine);
+  assert(!isNil(firstLine), "first line is nil");
   buf.push(color(firstLine));
 
   // color the rest of the lines