From e9d485b7f60fe854db407ae3bbd767a5eb30feec Mon Sep 17 00:00:00 2001
From: James Shubin <james@shubin.ca>
Date: Fri, 9 May 2025 01:08:12 -0400
Subject: [PATCH] lang: ast, core: Add some safety checks

I don't think I'm hitting these, but good for debugging.
---
 lang/ast/structs.go  | 22 ++++++++++++++++++++++
 lang/core/collect.go |  3 +++
 2 files changed, 25 insertions(+)

diff --git a/lang/ast/structs.go b/lang/ast/structs.go
index 38b80ac5..f3c2daa8 100644
--- a/lang/ast/structs.go
+++ b/lang/ast/structs.go
@@ -868,9 +868,18 @@ func (obj *StmtRes) Output(table map[interfaces.Func]types.Value) (*interfaces.O
 			}
 
 			s := name.Str() // must not panic
+			if s == "" {
+				return nil, fmt.Errorf("empty name")
+			}
 			names = append(names, s)
 			// host is the input telling us who we want to pull from
 			hosts[s] = host.Str() // correspondence map
+			if hosts[s] == "" {
+				return nil, fmt.Errorf("empty host")
+			}
+			if hosts[s] == "*" { // safety
+				return nil, fmt.Errorf("invalid star host")
+			}
 		}
 		for n, m := range mapping { // delete everything else
 			if !util.StrInList(n, names) {
@@ -999,6 +1008,19 @@ func (obj *StmtRes) collect(table map[interfaces.Func]types.Value) (map[string]m
 		n := name.Str() // must not panic
 		h := host.Str() // must not panic
 
+		if n == "" {
+			// programming error
+			return nil, fmt.Errorf("name field is empty")
+		}
+		if h == "" {
+			// programming error
+			return nil, fmt.Errorf("host field is empty")
+		}
+		if h == "*" {
+			// programming error
+			return nil, fmt.Errorf("host field is a start")
+		}
+
 		if _, exists := m[n]; !exists {
 			m[n] = make(map[string]string)
 		}
diff --git a/lang/core/collect.go b/lang/core/collect.go
index 692661da..ac679cb7 100644
--- a/lang/core/collect.go
+++ b/lang/core/collect.go
@@ -482,6 +482,9 @@ func (obj *CollectFunc) Call(ctx context.Context, args []types.Value) (types.Val
 		if x.Host == "" {
 			return nil, fmt.Errorf("unexpected empty host")
 		}
+		if x.Host == "*" { // safety check
+			return nil, fmt.Errorf("unexpected star host")
+		}
 		if x.Data == "" {
 			return nil, fmt.Errorf("unexpected empty data")
 		}