embedded version does not match detected version - update…

Error message

embedded version %s does not match detected version %s - update required

What it means

checkEmbeddedVersion extracts the version recorded in the previously generated file and compares it to the CLI version detected for the current build. If they differ, it aborts with this message stating that an update is required, preventing a bundle that embeds a mismatched CLI version.

Solutions

Rerun the bundler so the embedded version file is regenerated for the newly detected version
Delete the stale generated version file so the check is skipped (no existing file means nothing to verify) and rebuild
Pin the detected CLI to the embedded version (install the matching CLI release) if you must keep the old embed
Investigate why versions diverge — check CI caching and which CLI source (local vs downloaded) feeds detectedVersion

Example fix

// before
// bundler aborts: embedded version 1.2.3 does not match detected 1.3.0
// after
$ rm go/internal/embeddedcli/version_gen.go && bundler build   # regenerate embed for detected version

Defensive patterns

Strategy: validation

Validate before calling

// before bundling, confirm the embedded version matches the CLI you will bundle
version, _ := readEmbeddedVersion(goFilePath)
if version != detectedVersion { /* regenerate embed or pin CLI */ }

Try / catch

// Go
if err := checkEmbeddedVersion(detected, goos, goarch, outDir); err != nil {
	return fmt.Errorf("regenerate embedded version file and retry: %w", err)
}

Prevention

Always rerun the full bundler pipeline after a CLI version bump
Avoid restoring stale generated files from CI caches
Pin the CLI version used for detection and embedding together

When it happens

Trigger: The detected CLI version (from the downloaded/installed CLI) changed since the embedded version file was last generated — e.g. after a CLI upgrade, a branch switch that changed the embedded file, or running the bundler against a different CLI version than the code embeds.

Common situations: Upgrading the Copilot CLI dependency without rerunning the full bundler pipeline; merging a branch where the embedded version file was hand-edited; CI cache restoring an outdated generated file while fetching a newer CLI.

Understand the failure class

Background: "is not a compatible type" / "cannot merge" errors: when a value's type doesn't match what the library requires — this error's family across 65 libraries.

Related errors

AI-assisted analysis of github/copilot-sdk@cd8cf15dc3 (2026-09-09). Data as JSON: /api/errors/fbc04a2bea51f526. Report an issue: GitHub.

Appendix: source

Thrown at go/cmd/bundler/main.go:1313

		}
		return fmt.Errorf("failed to read existing Go file: %w", err)
	}

	// Extract version from the generated file
	// Looking for: Version: "x.y.z",
	re := regexp.MustCompile(`Version:\s*"([^"]+)"`)
	matches := re.FindSubmatch(data)
	if matches == nil {
		// Can't parse version, skip check
		return nil
	}

	embeddedVersion := string(matches[1])
	fmt.Printf("Found existing embedded version: %s\n", embeddedVersion)

	// Compare versions
	if embeddedVersion != detectedVersion {
		return fmt.Errorf("embedded version %s does not match detected version %s - update required", embeddedVersion, detectedVersion)
	}

	fmt.Printf("Embedded version is up to date (%s)\n", embeddedVersion)
	return nil
}

View on GitHub (pinned to cd8cf15dc3)