checker: disallow duplicate export names (fix #25301) (#25302)

Author: kbkpbot

vlib/v/ast/table.v

@@ -99,8 +99,9 @@ pub mut:
 	anon_union_names    map[string]int // anon union name -> union sym idx
 	anon_union_counter  int
 	comptime_is_true    map[string]ComptTimeCondResult // The evaluate cond results for different generic types combination, such as `comptime_is_true['T=int,X=string|main.v|pos ...'] = {true, '!DEFINED(WINDOWS)'}`
-	new_int             bool // use 64bit/32bit platform dependent `int`
-	new_int_fmt_fix     bool // vfmt will fix `int` to `i32`
+	new_int             bool              // use 64bit/32bit platform dependent `int`
+	new_int_fmt_fix     bool              // vfmt will fix `int` to `i32`
+	export_names        map[string]string // @[export] names
 }
 
 pub struct ComptTimeCondResult {

vlib/v/checker/checker.v

@@ -1937,6 +1937,13 @@ fn (mut c Checker) const_decl(mut node ast.ConstDecl) {
 		c.warn('const () groups will be an error after 2025-01-01 (`v fmt -w source.v` will fix that for you)',
 			node.pos)
 	}
+
+	mut is_export := false
+	mut export_name := ''
+	if export_attr := node.attrs.find_first('export') {
+		is_export = true
+		export_name = export_attr.arg
+	}
 	for mut field in node.fields {
 		if reserved_type_names_chk.matches(util.no_cur_mod(field.name, c.mod)) {
 			c.error('invalid use of reserved type `${field.name}` as a const name', field.pos)
@@ -1949,6 +1956,21 @@ fn (mut c Checker) const_decl(mut node ast.ConstDecl) {
 			}
 			c.error('duplicate const `${field.name}`', name_pos)
 		}
+		if is_export {
+			check_name := if export_name.len == 0 { field.name } else { export_name }
+			if !check_name.is_identifier() {
+				c.error('export name `${check_name}` should be a valid identifier', node.pos)
+			}
+			if check_name in c.table.export_names.values() {
+				name_pos := token.Pos{
+					...field.pos
+					len: util.no_cur_mod(field.name, c.mod).len
+				}
+				c.error('duplicate export name `${check_name}`', name_pos)
+			} else {
+				c.table.export_names[field.name] = check_name
+			}
+		}
 		if field.expr is ast.CallExpr {
 			sym := c.table.sym(c.check_expr_option_or_result_call(field.expr, c.expr(mut field.expr)))
 			if sym.kind == .multi_return {
@@ -2522,6 +2544,12 @@ fn (mut c Checker) global_decl(mut node ast.GlobalDecl) {
 		if '${c.mod}.${field.name}' in c.const_names {
 			c.error('duplicate global and const `${field.name}`', field.pos)
 		}
+		if field.name in c.table.export_names.values() {
+			c.error('duplicate export name `${field.name}`', field.pos)
+		} else {
+			// add global to exports for duplicate check
+			c.table.export_names[field.name] = field.name
+		}
 		sym := c.table.sym(field.typ)
 		if sym.kind == .placeholder {
 			c.error('unknown type `${sym.name}`', field.typ_pos)

vlib/v/checker/fn.v

@@ -115,6 +115,22 @@ fn (mut c Checker) fn_decl(mut node ast.FnDecl) {
 			if attr := node.attrs.find_first(attr_name) {
 				if attr.arg == '' {
 					c.error('missing argument for @[${attr_name}] attribute', attr.pos)
+				} else if attr_name == 'export' {
+					// export fn name
+					fn_name := attr.arg
+					if !fn_name.is_identifier() {
+						c.error('export name `${fn_name}` should be a valid identifier',
+							node.pos)
+					}
+					if fn_name in c.table.export_names.values() {
+						c.error('duplicate export name `${fn_name}`', node.pos)
+					} else {
+						mut node_name := node.name
+						if node.is_method {
+							node_name = c.table.type_to_str(node.receiver.typ) + '.' + node_name
+						}
+						c.table.export_names[node_name] = fn_name
+					}
 				}
 			}
 		}

vlib/v/checker/tests/redfine_global_const_fn_names.out

@@ -0,0 +1,28 @@
+vlib/v/checker/tests/redfine_global_const_fn_names.vv:10:7: error: duplicate export name `abc`
+    8 | 
+    9 | @[export: 'abc']
+   10 | const abc2 = 3
+      |       ~~~~
+   11 | 
+   12 | @[export: 'fn1']
+vlib/v/checker/tests/redfine_global_const_fn_names.vv:4:10: error: duplicate export name `abc`
+    2 | module main
+    3 | 
+    4 | __global abc = 1
+      |          ~~~
+    5 | 
+    6 | @[export: 'abc']
+vlib/v/checker/tests/redfine_global_const_fn_names.vv:17:1: error: duplicate export name `fn1`
+   15 | 
+   16 | @[export: 'fn1']
+   17 | fn fn_abc2() {
+      | ~~~~~~~~~~~~
+   18 | }
+   19 |
+vlib/v/checker/tests/redfine_global_const_fn_names.vv:21:1: error: export name `abc.dd` should be a valid identifier
+   19 | 
+   20 | @[export: 'abc.dd']
+   21 | fn fn_abc3() {
+      | ~~~~~~~~~~~~
+   22 | }
+   23 |

vlib/v/checker/tests/redfine_global_const_fn_names.vv

@@ -0,0 +1,26 @@
+@[has_globals]
+module main
+
+__global abc = 1
+
+@[export: 'abc']
+const abc1 = 2
+
+@[export: 'abc']
+const abc2 = 3
+
+@[export: 'fn1']
+fn fn_abc1() {
+}
+
+@[export: 'fn1']
+fn fn_abc2() {
+}
+
+@[export: 'abc.dd']
+fn fn_abc3() {
+}
+
+@[export: xyz]
+fn fn_xyz() {
+}