v test-fmt: add 1 sec sleep before rebuilding vfmt, to avoid its parallel recompilation afterwards

cmd/tools/vtest-fmt.v

@@ -1,6 +1,7 @@
 module main
 
 import os
+import time
 import testing
 import v.util
 
@@ -62,6 +63,7 @@ fn prepare_vfmt_when_needed() {
 	vroot := os.dir(vexe)
 	vfmtv := os.join_path(vroot, 'cmd', 'tools', 'vfmt.v')
 	if util.should_recompile_tool(vexe, vfmtv) {
+		time.sleep_ms(1001) // TODO: remove this when we can get mtime with a better resolution
 		recompile_file(vexe, vfmtv)
 	}
 }

vlib/v/util/util.v

@@ -166,6 +166,9 @@ pub fn launch_tool(is_verbose bool, tool_name string, args []string) {
 	exit(os.system(tool_command))
 }
 
+// NB: should_recompile_tool/2 compares unix timestamps that have 1 second resolution
+// That means that a tool can get recompiled twice, if called in short succession.
+// TODO: use a nanosecond mtime timestamp, if available.
 pub fn should_recompile_tool(vexe string, tool_source string) bool {
 	sfolder := os.dir(tool_source)
 	tool_name := os.base(tool_source).replace('.v', '')