From 36862a18d676418f7b883f50bb00099b4fabef3c Mon Sep 17 00:00:00 2001
From: Vern Paxson <vern@corelight.com>
Date: Sun, 31 Aug 2025 15:14:26 -0700
Subject: [PATCH] tightened up parsing of $field=X record constructor
 expressions

---
 src/parse.y                                   | 63 ++++++++++++-------
 .../Baseline/language.bogus-field-assign/out  |  2 +
 .../Baseline/language.record-bad-ctor3/out    |  2 +-
 .../btest/language/bogus-field-assign.zeek    |  6 ++
 4 files changed, 51 insertions(+), 22 deletions(-)
 create mode 100644 testing/btest/Baseline/language.bogus-field-assign/out
 create mode 100644 testing/btest/language/bogus-field-assign.zeek

diff --git a/src/parse.y b/src/parse.y
index ea4fc7ae26..03b77683af 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -61,7 +61,7 @@
 %type <id_l> local_id_list case_type_list
 %type <ic> init_class
 %type <val> TOK_CONSTANT
-%type <expr> expr opt_expr rhs opt_init anonymous_function lambda_body index_slice opt_deprecated when_condition
+%type <expr> expr opt_expr rhs opt_init anonymous_function lambda_body index_slice opt_deprecated when_condition field_assign
 %type <event_expr> event
 %type <stmt> stmt stmt_list func_body for_head
 %type <type> simple_type type opt_type enum_body
@@ -70,7 +70,7 @@
 %type <type_decl> type_decl formal_args_decl
 %type <type_decl_l> type_decl_list formal_args_decl_list
 %type <record> formal_args
-%type <list> expr_list opt_expr_list rhs_expr_list
+%type <list> expr_list opt_expr_list rhs_expr_list opt_exprs_or_field_assigns field_assigns
 %type <c_case> case
 %type <case_l> case_list
 %type <attr> attr
@@ -756,22 +756,6 @@ expr:
 			$$ = new FieldExpr({AdoptRef{}, $1}, $3);
 			}
 
-	|	'$' TOK_ID '=' expr
-			{
-			set_location(@1, @4);
-			$$ = new FieldAssignExpr($2, {AdoptRef{}, $4});
-			}
-
-	|	'$' TOK_ID begin_lambda '='
-			{
-			func_hdr_location = @1;
-			$3->SetInferReturnType(true);
-			}
-		lambda_body
-			{
-			$$ = new FieldAssignExpr($2, IntrusivePtr{AdoptRef{}, $6});
-			}
-
 	|	expr TOK_IN expr
 			{
 			set_location(@1, @3);
@@ -786,7 +770,7 @@ expr:
 			        ExprPtr{AdoptRef{}, $3}));
 			}
 
-	|	'[' opt_expr_list ']'
+	|	'[' opt_exprs_or_field_assigns ']'
 			{
 			set_location(@1, @3);
 
@@ -810,7 +794,7 @@ expr:
 				$$ = $2;
 			}
 
-	|	TOK_RECORD '(' expr_list ')'
+	|	TOK_RECORD '(' field_assigns expr_list_opt_comma ')'
 			{
 			set_location(@1, @4);
 			$$ = new RecordConstructorExpr({AdoptRef{}, $3});
@@ -843,7 +827,7 @@ expr:
 				++in_init;
 			}
 
-		opt_expr_list
+		opt_exprs_or_field_assigns
 			{
 			if ( expr_is_table_type_name($1) )
 				--in_init;
@@ -1018,6 +1002,43 @@ expr:
 			}
 	;
 
+opt_exprs_or_field_assigns:
+		{ $$ = new ListExpr(); }
+	| expr_list expr_list_opt_comma
+	| field_assigns expr_list_opt_comma
+	;
+
+field_assigns:
+		field_assigns ',' field_assign
+			{
+			set_location(@1, @3);
+			$1->Append({AdoptRef{}, $3});
+			}
+	|	field_assign
+			{
+			set_location(@1);
+			expr_list_has_opt_comma = 0;
+			$$ = new ListExpr({AdoptRef{}, $1});
+			}
+	;
+
+field_assign:	'$' TOK_ID '=' expr
+			{
+			set_location(@1, @4);
+			$$ = new FieldAssignExpr($2, {AdoptRef{}, $4});
+			}
+
+	|	'$' TOK_ID begin_lambda '='
+			{
+			func_hdr_location = @1;
+			$3->SetInferReturnType(true);
+			}
+		lambda_body
+			{
+			$$ = new FieldAssignExpr($2, IntrusivePtr{AdoptRef{}, $6});
+			}
+	;
+
 rhs:		'{' { ++in_init; } rhs_expr_list '}'
 			{
 			--in_init;
diff --git a/testing/btest/Baseline/language.bogus-field-assign/out b/testing/btest/Baseline/language.bogus-field-assign/out
new file mode 100644
index 0000000000..fc5f26152f
--- /dev/null
+++ b/testing/btest/Baseline/language.bogus-field-assign/out
@@ -0,0 +1,2 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/bogus-field-assign.zeek, line 6: syntax error, at or near "$"
diff --git a/testing/btest/Baseline/language.record-bad-ctor3/out b/testing/btest/Baseline/language.record-bad-ctor3/out
index 4903963619..a8c5997f8f 100644
--- a/testing/btest/Baseline/language.record-bad-ctor3/out
+++ b/testing/btest/Baseline/language.record-bad-ctor3/out
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/record-bad-ctor3.zeek, line 13: bad type in record constructor ([$x=a + 5, a + 9] and a + 9)
+error in <...>/record-bad-ctor3.zeek, line 13: syntax error, at or near "a"
diff --git a/testing/btest/language/bogus-field-assign.zeek b/testing/btest/language/bogus-field-assign.zeek
new file mode 100644
index 0000000000..c29e6e6dde
--- /dev/null
+++ b/testing/btest/language/bogus-field-assign.zeek
@@ -0,0 +1,6 @@
+# @TEST-EXEC-FAIL: zeek -b %INPUT >out 2>&1
+# @TEST-EXEC: TEST_DIFF_CANONIFIER=$SCRIPTS/diff-remove-abspath btest-diff out
+
+# Zeek used to happily print the value of "5" here.
+
+print $foo=5;