fix(terraform): avoid oom parsing empty file (#12182)

lib/manager/terraform/providers.ts

@@ -36,7 +36,8 @@ export function extractTerraformProvider(
     }
 
     const line = lines[lineNumber];
-    if (line) {
+    // istanbul ignore next
+    if (is.string(line)) {
       // `{` will be counted wit +1 and `}` with -1. Therefore if we reach braceCounter == 0. We have found the end of the terraform block
       const openBrackets = (line.match(/\{/g) || []).length;
       const closedBrackets = (line.match(/\}/g) || []).length;
@@ -54,6 +55,9 @@ export function extractTerraformProvider(
           }
         }
       }
+    } else {
+      // stop - something went wrong
+      braceCounter = 0;
     }
     lineNumber += 1;
   } while (braceCounter !== 0);