fix: fix symbol checking and creation for subst with a regexp

internal/runtime/compiler/checker/checker.go

@@ -35,6 +35,7 @@ type checker struct {
 	tooDeep           bool
 	maxRecursionDepth int
 	maxRegexLength    int
+	noRegexSymbols    bool
 }
 
 // Check performs a semantic check of the astNode, and returns a potentially
@@ -83,6 +84,12 @@ func (c *checker) VisitBefore(node ast.Node) (ast.Visitor, ast.Node) {
 		glog.V(2).Infof("Created new scope %v in condstmt", n.Scope)
 		return c, n
 
+	case *ast.BuiltinExpr:
+		if n.Name == "subst" {
+			c.noRegexSymbols = true
+		}
+		return c, n
+
 	case *ast.CaprefTerm:
 		if n.Symbol == nil {
 			sym := c.scope.Lookup(n.Name, symbol.CaprefSymbol)
@@ -821,6 +828,10 @@ func (c *checker) VisitAfter(node ast.Node) ast.Node {
 				return n
 			}
 
+		case "subst":
+			c.noRegexSymbols = false
+			return n
+
 		case "tolower":
 			if !types.Equals(gotType.Args[0], types.String) {
 				c.errors.Add(n.Args.(*ast.ExprList).Children[0].Pos(), fmt.Sprintf("Expecting a String for argument 1 of tolower(), not %v.", gotType.Args[0]))
@@ -875,6 +886,10 @@ func (c *checker) checkRegex(pattern string, n ast.Node) {
 		return
 	}
 	if reAst, err := types.ParseRegexp(pattern); err == nil {
+		if c.noRegexSymbols {
+			return
+		}
+
 		// We reserve the names of the capturing groups as declarations
 		// of those symbols, so that future CAPREF tokens parsed can
 		// retrieve their value.  By recording them in the symbol table, we

internal/runtime/compiler/checker/checker_test.go

@@ -67,6 +67,13 @@ var checkerInvalidPrograms = []struct {
 		[]string{"invalid regex 3:1:1-24: error parsing regexp: invalid character class range: `[:alph:]`"},
 	},
 
+	{
+		"subst invalid regex",
+		`subst(/foo(/, "", "")
+`,
+		[]string{"subst invalid regex:1:7-12: error parsing regexp: missing closing ): `foo(`"},
+	},
+
 	{
 		"duplicate declaration",
 		"counter foo\ncounter foo\n",
@@ -275,6 +282,13 @@ m`,
 		[]string{"regexp too long:1:1-1027: Exceeded maximum regular expression pattern length of 1024 bytes with 1025.", "\tExcessively long patterns are likely to cause compilation and runtime performance problems."},
 	},
 
+	{
+		"subst regexp too long",
+		"subst(/" + strings.Repeat("c", 1025) + `/, "", "")
+`,
+		[]string{"subst regexp too long:1:7-1033: Exceeded maximum regular expression pattern length of 1024 bytes with 1025.", "\tExcessively long patterns are likely to cause compilation and runtime performance problems."},
+	},
+
 	{
 		"strptime invalid args",
 		`strptime("",8)
@@ -576,6 +590,11 @@ foo = subst(",", "", $1)
 }`},
 	{"regexp subst", `
 subst(/\d+/, "d", "1234")
+`},
+	{"regexp subst twice", `
+text value
+value = subst(/[a-zA-Z]+/, "a", "1234abcd")
+value = subst(/\d+/, "d", value)
 `},
 }