Watch: Clear vars cache between runs

Closes #365

CHANGELOG.md

@@ -4,7 +4,7 @@
 
 - The watch feature (via the `--watch` flag) got a few different bug fixes and
   should be more stable now
-  ([#423](https://github.com/go-task/task/pull/423)).
+  ([#423](https://github.com/go-task/task/pull/423), [#365](https://github.com/go-task/task/issues/365)).
 
 ## v3.1.0
 

internal/compiler/compiler.go

@@ -9,4 +9,5 @@ import (
 type Compiler interface {
 	GetVariables(t *taskfile.Task, call taskfile.Call) (*taskfile.Vars, error)
 	HandleDynamicVar(v taskfile.Var) (string, error)
+	ResetCache()
 }

internal/compiler/v2/compiler_v2.go

@@ -109,3 +109,11 @@ func (c *CompilerV2) HandleDynamicVar(v taskfile.Var) (string, error) {
 
 	return result, nil
 }
+
+// ResetCache clear the dymanic variables cache
+func (c *CompilerV2) ResetCache() {
+	c.muDynamicCache.Lock()
+	defer c.muDynamicCache.Unlock()
+
+	c.dynamicCache = nil
+}

internal/compiler/v3/compiler_v3.go

@@ -96,3 +96,11 @@ func (c *CompilerV3) HandleDynamicVar(v taskfile.Var) (string, error) {
 
 	return result, nil
 }
+
+// ResetCache clear the dymanic variables cache
+func (c *CompilerV3) ResetCache() {
+	c.muDynamicCache.Lock()
+	defer c.muDynamicCache.Unlock()
+
+	c.dynamicCache = nil
+}

watch.go

@@ -49,6 +49,9 @@ func (e *Executor) watchTasks(calls ...taskfile.Call) error {
 
 				cancel()
 				ctx, cancel = context.WithCancel(context.Background())
+
+				e.Compiler.ResetCache()
+
 				for _, c := range calls {
 					c := c
 					go func() {