parser,ast,checker: add support for `[deprecated: "use another module"] module obsolete`

vlib/v/ast/table.v

@@ -4,6 +4,7 @@
 [has_globals]
 module ast
 
+import time
 import v.cflag
 import v.token
 import v.util
@@ -36,8 +37,10 @@ pub mut:
 	cur_fn             &FnDecl = 0 // previously stored in Checker.cur_fn and Gen.cur_fn
 	cur_concrete_types []Type  // current concrete types, e.g. <int, string>
 	gostmts            int     // how many `go` statements there were in the parsed files.
-	enum_decls         map[string]EnumDecl
 	// When table.gostmts > 0, __VTHREADS__ is defined, which can be checked with `$if threads {`
+	enum_decls        map[string]EnumDecl
+	mdeprecated_msg   map[string]string    // module deprecation message
+	mdeprecated_after map[string]time.Time // module deprecation date
 }
 
 // used by vls to avoid leaks
@@ -301,6 +304,15 @@ pub fn (t &Table) known_fn(name string) bool {
 	return true
 }
 
+pub fn (mut t Table) mark_module_as_deprecated(mname string, message string) {
+	t.mdeprecated_msg[mname] = message
+	t.mdeprecated_after[mname] = time.now()
+}
+
+pub fn (mut t Table) mark_module_as_deprecated_after(mname string, after_date string) {
+	t.mdeprecated_after[mname] = time.parse_iso8601(after_date) or { time.now() }
+}
+
 pub fn (mut t Table) register_fn(new_fn Fn) {
 	t.fns[new_fn.name] = new_fn
 }

vlib/v/checker/checker.v

@@ -3,6 +3,7 @@
 module checker
 
 import os
+import time
 import v.ast
 import v.vmod
 import v.token
@@ -2240,6 +2241,11 @@ fn (mut c Checker) import_stmt(node ast.Import) {
 		}
 		c.error('module `$node.mod` has no constant or function `$sym.name`', sym.pos)
 	}
+	if after_time := c.table.mdeprecated_after[node.mod] {
+		now := time.now()
+		deprecation_message := c.table.mdeprecated_msg[node.mod]
+		c.deprecate('module', node.mod, deprecation_message, now, after_time, node.pos)
+	}
 }
 
 // stmts should be used for processing normal statement lists (fn bodies, for loop bodies etc).

vlib/v/checker/fn.v

@@ -1439,7 +1439,6 @@ pub fn (mut c Checker) method_call(mut node ast.CallExpr) ast.Type {
 }
 
 fn (mut c Checker) deprecate_fnmethod(kind string, name string, the_fn ast.Fn, node ast.CallExpr) {
-	start_message := '$kind `$name`'
 	mut deprecation_message := ''
 	now := time.now()
 	mut after_time := now
@@ -1454,19 +1453,24 @@ fn (mut c Checker) deprecate_fnmethod(kind string, name string, the_fn ast.Fn, n
 			}
 		}
 	}
+	c.deprecate(kind, name, deprecation_message, now, after_time, node.pos)
+}
+
+fn (mut c Checker) deprecate(kind string, name string, deprecation_message string, now time.Time, after_time time.Time, pos token.Pos) {
+	start_message := '$kind `$name`'
 	error_time := after_time.add_days(180)
 	if error_time < now {
 		c.error(semicolonize('$start_message has been deprecated since $after_time.ymmdd()',
-			deprecation_message), node.pos)
+			deprecation_message), pos)
 	} else if after_time < now {
 		c.warn(semicolonize('$start_message has been deprecated since $after_time.ymmdd(), it will be an error after $error_time.ymmdd()',
-			deprecation_message), node.pos)
+			deprecation_message), pos)
 	} else if after_time == now {
 		c.warn(semicolonize('$start_message has been deprecated', deprecation_message),
-			node.pos)
+			pos)
 	} else {
 		c.note(semicolonize('$start_message will be deprecated after $after_time.ymmdd(), and will become an error after $error_time.ymmdd()',
-			deprecation_message), node.pos)
+			deprecation_message), pos)
 	}
 }
 

vlib/v/checker/tests/modules/deprecated_module.out

@@ -0,0 +1,12 @@
+vlib/v/checker/tests/modules/deprecated_module/main.v:2:1: notice: module `deprecated_module.www.ttt` will be deprecated after 2999-01-01, and will become an error after 2999-06-30; use xxx.yyy
+    1 | import deprecated_module.bbb.ccc
+    2 | import deprecated_module.www.ttt
+      | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    3 | import deprecated_module.xxx.yyy
+    4 |
+vlib/v/checker/tests/modules/deprecated_module/main.v:12:11: error: undefined ident: `deprecated_module.www.ttt.non_existing`
+   10 |     dump(ttt.f())
+   11 |     dump(yyy.f())
+   12 |     dump(ttt.non_existing)
+      |              ~~~~~~~~~~~~
+   13 | }

vlib/v/checker/tests/modules/deprecated_module/bbb/ccc/ccc.v

@@ -0,0 +1,5 @@
+module ccc
+
+pub fn f() int {
+	return 142
+}

vlib/v/checker/tests/modules/deprecated_module/main.v

@@ -0,0 +1,13 @@
+import deprecated_module.bbb.ccc
+import deprecated_module.www.ttt
+import deprecated_module.xxx.yyy
+
+// NB: www.ttt has been deprecated.
+// => compiling this should produce an error,
+// showing the deprecation message
+fn main() {
+	dump(ccc.f())
+	dump(ttt.f())
+	dump(yyy.f())
+	dump(ttt.non_existing)
+}

vlib/v/checker/tests/modules/deprecated_module/www/ttt/ttt.v

@@ -0,0 +1,7 @@
+[deprecated: 'use xxx.yyy']
+[deprecated_after: '2999-01-01']
+module ttt
+
+pub fn f() int {
+	return 1142
+}

vlib/v/checker/tests/modules/deprecated_module/xxx/yyy/yyy.v

@@ -0,0 +1,5 @@
+module yyy
+
+pub fn f() int {
+	return 42
+}

vlib/v/fmt/fmt.v

@@ -478,7 +478,7 @@ pub fn (mut f Fmt) stmt(node ast.Stmt) {
 			f.interface_decl(node)
 		}
 		ast.Module {
-			f.mod(node)
+			f.module_stmt(node)
 		}
 		ast.Return {
 			f.return_stmt(node)
@@ -1135,7 +1135,7 @@ pub fn (mut f Fmt) interface_method(method ast.FnDecl) {
 	f.mark_types_import_as_used(method.return_type)
 }
 
-pub fn (mut f Fmt) mod(mod ast.Module) {
+pub fn (mut f Fmt) module_stmt(mod ast.Module) {
 	f.set_current_module_name(mod.name)
 	if mod.is_skipped {
 		return

vlib/v/parser/parser.v

@@ -2967,16 +2967,19 @@ fn (mut p Parser) parse_number_literal() ast.Expr {
 fn (mut p Parser) module_decl() ast.Module {
 	mut module_attrs := []ast.Attr{}
 	mut attrs_pos := p.tok.pos()
-	if p.tok.kind == .lsbr {
+	for p.tok.kind == .lsbr {
 		p.attributes()
-		module_attrs = p.attrs
 	}
+	module_attrs << p.attrs
 	mut name := 'main'
-	is_skipped := p.tok.kind != .key_module
 	mut module_pos := token.Pos{}
 	mut name_pos := token.Pos{}
 	mut mod_node := ast.Module{}
-	if !is_skipped {
+	is_skipped := p.tok.kind != .key_module
+	if is_skipped {
+		// the attributes were for something else != module, like a struct/fn/type etc.
+		module_attrs = []
+	} else {
 		p.attrs = []
 		module_pos = p.tok.pos()
 		p.next()
@@ -3020,6 +3023,14 @@ fn (mut p Parser) module_decl() ast.Module {
 	if !is_skipped {
 		for ma in module_attrs {
 			match ma.name {
+				'deprecated' {
+					// [deprecated: 'use a replacement']
+					p.table.mark_module_as_deprecated(p.mod, ma.arg)
+				}
+				'deprecated_after' {
+					// [deprecated_after: '2027-12-30']
+					p.table.mark_module_as_deprecated_after(p.mod, ma.arg)
+				}
 				'manualfree' {
 					p.is_manualfree = true
 				}