From d771cdfc11bc789b501b1e786ee4ec14841855ae Mon Sep 17 00:00:00 2001
From: Dennis Jekubczyk <dennis.jekubczyk@gmail.com>
Date: Sun, 12 Mar 2023 12:26:07 +0100
Subject: [PATCH 1/4] add test to prove that predefined environment variables
 take precedence

---
 task_test.go                        | 27 +++++++++++++++++++++++++++
 testdata/env_override/.gitignore    |  1 +
 testdata/env_override/Taskfile.yaml | 10 ++++++++++
 3 files changed, 38 insertions(+)
 create mode 100644 testdata/env_override/.gitignore
 create mode 100644 testdata/env_override/Taskfile.yaml

diff --git a/task_test.go b/task_test.go
index beebdc5b4d..df493733fe 100644
--- a/task_test.go
+++ b/task_test.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -13,6 +14,7 @@ import (
 
 	"github.com/Masterminds/semver/v3"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/go-task/task/v3"
 	"github.com/go-task/task/v3/internal/filepathext"
@@ -1832,3 +1834,28 @@ func TestBashShellOptsCommandLevel(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, "globstar\ton\n", buff.String())
 }
+
+func TestOverwriteEnvironment(t *testing.T) {
+	binary := buildTask(t)
+
+	cmd := exec.Command(binary)
+	cmd.Dir = "testdata/env_override"
+	cmd.Env = []string{"PREDEFINED=initial"}
+	require.NoError(t, cmd.Run())
+
+	output, err := os.ReadFile("testdata/env_override/output.txt")
+	require.NoError(t, err)
+	require.Equal(t, "PREDEFINED='overwritten'", string(output))
+}
+
+func buildTask(t *testing.T) string {
+	temp := t.TempDir()
+
+	binary := filepath.Join(temp, "task")
+	command := exec.Command("go", "build", "-o", binary, "cmd/task/task.go")
+	command.Stdout = os.Stdout
+	command.Stderr = os.Stderr
+	require.NoError(t, command.Run())
+
+	return binary
+}
diff --git a/testdata/env_override/.gitignore b/testdata/env_override/.gitignore
new file mode 100644
index 0000000000..2211df63dd
--- /dev/null
+++ b/testdata/env_override/.gitignore
@@ -0,0 +1 @@
+*.txt
diff --git a/testdata/env_override/Taskfile.yaml b/testdata/env_override/Taskfile.yaml
new file mode 100644
index 0000000000..3c481c67f3
--- /dev/null
+++ b/testdata/env_override/Taskfile.yaml
@@ -0,0 +1,10 @@
+version: '3'
+
+silent: true
+
+tasks:
+  default:
+    env:
+      PREDEFINED: 'overwritten'
+    cmds:
+      - echo "PREDEFINED='$PREDEFINED'" > output.txt

From ea4e9fd4396469581869c6698508050771e21101 Mon Sep 17 00:00:00 2001
From: Dennis Jekubczyk <dennis.jekubczyk@gmail.com>
Date: Sun, 12 Mar 2023 12:32:21 +0100
Subject: [PATCH 2/4] override environment if locally defined in task file

---
 internal/env/env.go                 | 4 ----
 testdata/env_override/Taskfile.yaml | 2 +-
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/internal/env/env.go b/internal/env/env.go
index b18279c599..153b0f0517 100644
--- a/internal/env/env.go
+++ b/internal/env/env.go
@@ -20,10 +20,6 @@ func Get(t *taskfile.Task) []string {
 			continue
 		}
 
-		if _, alreadySet := os.LookupEnv(k); alreadySet {
-			continue
-		}
-
 		environ = append(environ, fmt.Sprintf("%s=%s", k, str))
 	}
 
diff --git a/testdata/env_override/Taskfile.yaml b/testdata/env_override/Taskfile.yaml
index 3c481c67f3..b50275772a 100644
--- a/testdata/env_override/Taskfile.yaml
+++ b/testdata/env_override/Taskfile.yaml
@@ -7,4 +7,4 @@ tasks:
     env:
       PREDEFINED: 'overwritten'
     cmds:
-      - echo "PREDEFINED='$PREDEFINED'" > output.txt
+      - echo -n "PREDEFINED='$PREDEFINED'" > output.txt

From b117af0bf5accfe7acb5014c1cd255081e1dad49 Mon Sep 17 00:00:00 2001
From: Dennis Jekubczyk <dennis.jekubczyk@gmail.com>
Date: Sun, 12 Mar 2023 12:44:14 +0100
Subject: [PATCH 3/4] only output build output on compilation error

---
 task_test.go | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/task_test.go b/task_test.go
index df493733fe..f2391a7ec9 100644
--- a/task_test.go
+++ b/task_test.go
@@ -1853,9 +1853,10 @@ func buildTask(t *testing.T) string {
 
 	binary := filepath.Join(temp, "task")
 	command := exec.Command("go", "build", "-o", binary, "cmd/task/task.go")
-	command.Stdout = os.Stdout
-	command.Stderr = os.Stderr
-	require.NoError(t, command.Run())
+	var output bytes.Buffer
+	command.Stdout = &output
+	command.Stderr = &output
+	require.NoError(t, command.Run(), &output)
 
 	return binary
 }

From 75505e29e1ed591a4aa135a71773c31cb4d62c59 Mon Sep 17 00:00:00 2001
From: Dennis Jekubczyk <dennis.jekubczyk@gmail.com>
Date: Sun, 12 Mar 2023 12:49:58 +0100
Subject: [PATCH 4/4] document that custom environment variables will take
 precedence

---
 docs/docs/usage.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/docs/usage.md b/docs/docs/usage.md
index cf8cb1f6f9..a54f282c13 100644
--- a/docs/docs/usage.md
+++ b/docs/docs/usage.md
@@ -119,6 +119,10 @@ tasks:
 
 ### Task
 
+:::info
+Custom environment variables will **overwrite** any predefined environment variables from your shell.
+:::info
+
 You can use `env` to set custom environment variables for a specific task:
 
 ```yaml