Protect against shimmed process usage in Vercel Edge (#5969)

* Protect against shimmed process usage in Vercel Edge

* Adding a changeset

2 files changed, 19 insertions, 4 deletions

diff --git a/.changeset/nasty-dolphins-cry.md b/.changeset/nasty-dolphins-cry.md
new file mode 100644
index 000000000..26437be43
--- /dev/null
+++ b/.changeset/nasty-dolphins-cry.md
@@ -0,0 +1,7 @@
+---
+'astro': patch
+---
+
+Fix usage of logger in Vercel Edge
+
+This protects against usage of `process` global in shimmed environments.
diff --git a/packages/astro/src/core/logger/core.ts b/packages/astro/src/core/logger/core.ts
index dc50d49e0..dbd2ae895 100644
--- a/packages/astro/src/core/logger/core.ts
+++ b/packages/astro/src/core/logger/core.ts
@@ -101,10 +101,18 @@ function padStr(str: string, len: number) {
 
 export let defaultLogLevel: LoggerLevel;
 if (typeof process !== 'undefined') {
-	if (process.argv.includes('--verbose')) {
-		defaultLogLevel = 'debug';
-	} else if (process.argv.includes('--silent')) {
-		defaultLogLevel = 'silent';
+	// This could be a shimmed environment so we don't know that `process` is the full
+	// NodeJS.process. This code treats it as a plain object so TS doesn't let us
+	// get away with incorrect assumptions.
+	let proc: object = process;
+	if('argv' in proc && Array.isArray(proc.argv)) {
+		if (proc.argv.includes('--verbose')) {
+			defaultLogLevel = 'debug';
+		} else if (proc.argv.includes('--silent')) {
+			defaultLogLevel = 'silent';
+		} else {
+			defaultLogLevel = 'info';
+		}
 	} else {
 		defaultLogLevel = 'info';
 	}