diff --git a/scripts/plot.py b/scripts/plot.py
index 3638a0cd..c775d0cb 100755
--- a/scripts/plot.py
+++ b/scripts/plot.py
@@ -283,7 +283,7 @@ def collect(csv_paths, defines=[]):
             with openio(path) as f:
                 reader = csv.DictReader(f, restval='')
                 fields.extend(
-                        k for k in reader.fieldnames
+                        k for k in reader.fieldnames or []
                             if k not in fields)
                 for r in reader:
                     # filter by matching defines
diff --git a/scripts/plotmpl.py b/scripts/plotmpl.py
index e16234b0..b6242e2e 100755
--- a/scripts/plotmpl.py
+++ b/scripts/plotmpl.py
@@ -207,7 +207,7 @@ def collect(csv_paths, defines=[]):
             with openio(path) as f:
                 reader = csv.DictReader(f, restval='')
                 fields.extend(
-                        k for k in reader.fieldnames
+                        k for k in reader.fieldnames or []
                             if k not in fields)
                 for r in reader:
                     # filter by matching defines
diff --git a/scripts/treemap.py b/scripts/treemap.py
index 57969373..2bc44565 100755
--- a/scripts/treemap.py
+++ b/scripts/treemap.py
@@ -83,7 +83,7 @@ def collect(csv_paths, defines=[]):
             with openio(path) as f:
                 reader = csv.DictReader(f, restval='')
                 fields.extend(
-                        k for k in reader.fieldnames
+                        k for k in reader.fieldnames or []
                             if k not in fields)
                 for r in reader:
                     # filter by matching defines
diff --git a/scripts/treemapd3.py b/scripts/treemapd3.py
index 878002e7..54dc83b3 100755
--- a/scripts/treemapd3.py
+++ b/scripts/treemapd3.py
@@ -100,7 +100,7 @@ def collect(csv_paths, defines=[]):
             with openio(path) as f:
                 reader = csv.DictReader(f, restval='')
                 fields.extend(
-                        k for k in reader.fieldnames
+                        k for k in reader.fieldnames or []
                             if k not in fields)
                 for r in reader:
                     # filter by matching defines
diff --git a/scripts/watch.py b/scripts/watch.py
index 3c0d66b5..59024e04 100755
--- a/scripts/watch.py
+++ b/scripts/watch.py
@@ -179,7 +179,7 @@ def main(command, *,
                         re.sub('^-.', '', p),
                         re.sub('^--[^=]+=', '', p)}:
                     if p and os.path.exists(p):
-                        paths.add(p)
+                        keep_open_paths.add(p)
 
     returncode = 0
     try: