builder: restore module import cycle detection/topological reorder

.github/workflows/ci.yml

@@ -272,6 +272,7 @@ jobs:
         .\make.bat -msvc
     - name: Fixed tests
       run: |
+        ./v -cg cmd\tools\vtest-fixed.v
         ./v test-fixed
 #    - name: Test
 #      run: |

vlib/builtin/builtin_windows.c.v

@@ -4,7 +4,7 @@
 
 module builtin
 
-#include <dbghelp.h>
+// dbghelp.h is already included in cheaders.v
 #flag windows -l dbghelp
 
 pub struct SymbolInfo {

vlib/v/ast/ast.v

@@ -465,6 +465,7 @@ pub:
 pub struct HashStmt {
 pub:
 	val string
+	mod string
 }
 
 // filter(), map()

vlib/v/builder/builder.v

@@ -14,6 +14,7 @@ import (
 	v.gen
 	v.gen.js
 	v.gen.x64
+	v.depgraph
 )
 
 pub struct Builder {
@@ -49,7 +50,9 @@ pub fn new_builder(pref &pref.Preferences) Builder {
 // parse all deps from already parsed files
 pub fn (b mut Builder) parse_imports() {
 	mut done_imports := []string
-	for i in 0 .. b.parsed_files.len {
+	// NB: b.parsed_files is appended in the loop,
+	// so we can not use the shorter `for in` form.
+	for i := 0; i<b.parsed_files.len; i++ {
 		ast_file := b.parsed_files[i]
 		for _, imp in ast_file.imports {
 			mod := imp.mod
@@ -80,6 +83,60 @@ pub fn (b mut Builder) parse_imports() {
 			done_imports << mod
 		}
 	}
+	b.resolve_deps()
+}
+
+
+pub fn (b mut Builder) resolve_deps() {
+	graph := b.import_graph()
+	deps_resolved := graph.resolve()
+	if !deps_resolved.acyclic {
+		eprintln('import cycle detected between the following modules: \n' + deps_resolved.display_cycles())
+		// TODO: error, when v itself does not have v.table -> v.ast -> v.table cycles anymore
+		return
+	}
+	if b.pref.is_verbose {
+		eprintln('------ resolved dependencies graph: ------')
+		eprintln(deps_resolved.display())
+		eprintln('------------------------------------------')
+	}
+	mut mods := []string
+	for node in deps_resolved.nodes {
+		mods << node.name
+	}
+	if b.pref.is_verbose {
+		eprintln('------ imported modules: ------')
+		eprintln(mods.str())
+		eprintln('-------------------------------')
+	}
+	mut reordered_parsed_files := []ast.File
+	for m in mods {
+		for pf in b.parsed_files {
+			if m == pf.mod.name {
+				reordered_parsed_files << pf
+				//eprintln('pf.mod.name: $pf.mod.name | pf.path: $pf.path')
+			}
+		}
+	}
+	b.parsed_files = reordered_parsed_files
+}
+
+// graph of all imported modules
+pub fn (b &Builder) import_graph() &depgraph.DepGraph {
+	mut builtins := util.builtin_module_parts
+	builtins << 'builtin'
+	mut graph := depgraph.new_dep_graph()
+	for p in b.parsed_files {
+		mut deps := []string
+		if p.mod.name !in builtins {
+			deps << 'builtin'
+		}
+		for _, m in p.imports {
+			deps << m.mod
+		}
+		graph.add(p.mod.name, deps)
+	}
+	return graph
 }
 
 pub fn (b Builder) v_files_from_dir(dir string) []string {

vlib/v/checker/tests/inout/enum_err.out

@@ -1,13 +1,14 @@
-vlib/v/checker/tests/inout/enum_err.v:2:13: error: default value for enum has to be an integer
-    1| enum Color {
-    2|     green = 'green',
+vlib/v/checker/tests/inout/enum_err.v:4:13: error: default value for enum has to be an integer
+    2| 
+    3| enum Color {
+    4|     green = 'green',
                    ~~~~~~~
-    3|     yellow = 1+1,
-    4|     blue,
-vlib/v/checker/tests/inout/enum_err.v:3:14: error: default value for enum has to be an integer
-    1| enum Color {
-    2|     green = 'green',
-    3|     yellow = 1+1,
+    5|     yellow = 1+1,
+    6|     blue,
+vlib/v/checker/tests/inout/enum_err.v:5:14: error: default value for enum has to be an integer
+    3| enum Color {
+    4|     green = 'green',
+    5|     yellow = 1+1,
                     ~~~
-    4|     blue,
-    5| }
+    6|     blue,
+    7| }

vlib/v/checker/tests/inout/enum_err.vv

@@ -1,5 +1,11 @@
+module main
+
 enum Color {
     green = 'green',
     yellow = 1+1,
     blue,
 }
+
+fn main(){
+	println('hello')
+}

vlib/v/checker/tests/inout/struct_name.vv

@@ -1,3 +1,5 @@
 struct abc {
 
 }
+
+fn main(){}

vlib/v/checker/tests/inout/unknown_field.out

@@ -1,6 +1,6 @@
-vlib/v/checker/tests/inout/unknown_field.v:7:12: error: unknown field `checker.Test.sdd`
+vlib/v/checker/tests/inout/unknown_field.v:7:12: error: unknown field `Test.sdd`
     5| fn main() {
     6|     t := Test{}
     7|     println(t.sdd)
                      ~~~
-    8| }
+    8| }

vlib/v/checker/tests/inout/unknown_field.vv

@@ -1,4 +1,4 @@
-module checker
+module main
 
 struct Test {}
 

vlib/v/checker/tests/inout/unknown_method.out

@@ -1,6 +1,6 @@
-vlib/v/checker/tests/inout/unknown_method.v:7:12: error: unknown method: checker.Test.sdd
+vlib/v/checker/tests/inout/unknown_method.v:7:12: error: unknown method: Test.sdd
     5| fn main() {
     6|     t := Test{}
     7|     println(t.sdd())
                      ~~~~~
-    8| }
+    8| }

vlib/v/checker/tests/inout/unknown_method.vv

@@ -1,4 +1,4 @@
-module checker
+module main
 
 struct Test {}
 

vlib/v/checker/tests/inout/void_fn_as_value.vv

@@ -1,4 +1,4 @@
-module checker
+module main
 
 fn main() {
   mut a := 'aa'

vlib/v/gen/cgen.v

@@ -25,13 +25,14 @@ fn foo(t token.Token) {
 
 struct Gen {
 	out                  strings.Builder
+	cheaders             strings.Builder
+	includes             strings.Builder // all C #includes required by V modules
 	typedefs             strings.Builder
 	typedefs2            strings.Builder
 	definitions          strings.Builder // typedefs, defines etc (everything that goes to the top of the file)
 	inits                strings.Builder // contents of `void _vinit(){}`
 	gowrappers           strings.Builder // all go callsite wrappers
 	stringliterals       strings.Builder // all string literals (they depend on tos3() beeing defined
-	includes             strings.Builder
 	table                &table.Table
 	pref                 &pref.Preferences
 mut:
@@ -76,13 +77,14 @@ pub fn cgen(files []ast.File, table &table.Table, pref &pref.Preferences) string
 	// println('start cgen2')
 	var g := Gen{
 		out: strings.new_builder(1000)
+		cheaders: strings.new_builder(8192)
+		includes: strings.new_builder(100)
 		typedefs: strings.new_builder(100)
 		typedefs2: strings.new_builder(100)
 		definitions: strings.new_builder(100)
 		gowrappers: strings.new_builder(100)
 		stringliterals: strings.new_builder(100)
 		inits: strings.new_builder(100)
-		includes: strings.new_builder(100)
 		table: table
 		pref: pref
 		fn_decl: 0
@@ -124,8 +126,15 @@ pub fn cgen(files []ast.File, table &table.Table, pref &pref.Preferences) string
 	}
 	//
 	g.finish()
-	return g.hashes() + g.includes.str() + g.typedefs.str() + g.typedefs2.str() + g.definitions.str() +
-		g.gowrappers.str() + g.stringliterals.str() + g.out.str()
+	return g.hashes() +
+		'\n// V typedefs:\n' + g.typedefs.str() +
+		'\n// V typedefs2:\n' + g.typedefs2.str() +
+		'\n// V cheaders:\n' + g.cheaders.str() +
+		'\n// V includes:\n' + g.includes.str() +
+		'\n// V definitions:\n' + g.definitions.str() +
+		'\n// V gowrappers:\n' + g.gowrappers.str() +
+		'\n// V stringliterals:\n' + g.stringliterals.str() +
+		'\n// V out\n' + g.out.str()
 }
 
 pub fn (g Gen) hashes() string {
@@ -135,10 +144,10 @@ pub fn (g Gen) hashes() string {
 }
 
 pub fn (g mut Gen) init() {
-	g.definitions.writeln('// Generated by the V compiler')
-	g.definitions.writeln('#include <inttypes.h>')	// int64_t etc
-	g.definitions.writeln(c_builtin_types)
-	g.definitions.writeln(c_headers)
+	g.cheaders.writeln('// Generated by the V compiler')
+	g.cheaders.writeln('#include <inttypes.h>')	// int64_t etc
+	g.cheaders.writeln(c_builtin_types)
+	g.cheaders.writeln(c_headers)
 	g.definitions.writeln('\nstring _STR(const char*, ...);\n')
 	g.definitions.writeln('\nstring _STR_TMP(const char*, ...);\n')
 	g.write_builtin_types()
@@ -478,7 +487,11 @@ fn (g mut Gen) stmt(node ast.Stmt) {
 		ast.HashStmt {
 			// #include etc
 			typ := it.val.all_before(' ')
-			if typ in ['include', 'define'] {
+			if typ == 'include' {
+				g.includes.writeln('// added by module `$it.mod`:')
+				g.includes.writeln('#$it.val')
+			}
+			if typ == 'define' {
 				g.definitions.writeln('#$it.val')
 			}
 		}

vlib/v/gen/cheaders.v

@@ -67,7 +67,6 @@ const (
 // c_headers
 #include <stdio.h>  // TODO remove all these includes, define all function signatures and types manually
 #include <stdlib.h>
-#include <float.h>
 
 //#include "fns.h"
 #include <signal.h>

vlib/v/parser/comptime.v

@@ -52,6 +52,7 @@ fn (p mut Parser) hash() ast.HashStmt {
 	}
 	return ast.HashStmt{
 		val: val
+		mod: p.mod
 	}
 }
 

vlib/v/parser/fn.v

@@ -7,6 +7,7 @@ import v.ast
 import v.table
 import v.scanner
 import v.token
+import v.util
 
 pub fn (p mut Parser) call_expr(is_c bool, is_js bool, mod string) ast.CallExpr {
 	first_pos := p.tok.position()
@@ -227,8 +228,7 @@ fn (p mut Parser) fn_decl() ast.FnDecl {
 		is_js: is_js
 		no_body: no_body
 		pos: pos
-		is_builtin: p.builtin_mod || p.mod in ['math', 'strconv', 'strconv.ftoa', 'hash.wyhash',
-			'math.bits', 'strings']
+		is_builtin: p.builtin_mod || p.mod in util.builtin_module_parts
 	}
 }
 

vlib/v/util/util.v

@@ -12,6 +12,10 @@ pub const (
 	v_version = '0.1.26'
 )
 
+pub const (
+	builtin_module_parts = ['math.bits' /* needed by strconv.ftoa */, 'strconv', 'strconv.ftoa', 'hash.wyhash', 'strings']
+)
+
 // vhash() returns the build string C.V_COMMIT_HASH . See cmd/tools/gen_vc.v .
 pub fn vhash() string {
 	mut buf := [50]byte