From abfb2c064ded02f7ee600d3715b183150e795a92 Mon Sep 17 00:00:00 2001
From: Anthony Poschen <zanven42@gmail.com>
Date: Mon, 26 Oct 2020 15:56:18 +1100
Subject: [PATCH 1/3] Add support for empty strings in target elements and
 compact func.

Signed-off-by: Anthony Poschen <zanven42@gmail.com>
---
 bake/bake.go | 3 +++
 bake/hcl.go  | 1 +
 2 files changed, 4 insertions(+)

diff --git a/bake/bake.go b/bake/bake.go
index e5ee0ca9..a8c7c37f 100644
--- a/bake/bake.go
+++ b/bake/bake.go
@@ -526,6 +526,9 @@ func removeDupes(s []string) []string {
 		if _, ok := seen[v]; ok {
 			continue
 		}
+		if v == "" {
+			continue
+		}
 		seen[v] = struct{}{}
 		s[i] = v
 		i++
diff --git a/bake/hcl.go b/bake/hcl.go
index 6f19390e..510d2e60 100644
--- a/bake/hcl.go
+++ b/bake/hcl.go
@@ -31,6 +31,7 @@ var (
 		"csvdecode":              stdlib.CSVDecodeFunc,
 		"coalesce":               stdlib.CoalesceFunc,
 		"coalescelist":           stdlib.CoalesceListFunc,
+		"compact":                stdlib.CompactFunc,
 		"concat":                 stdlib.ConcatFunc,
 		"contains":               stdlib.ContainsFunc,
 		"distinct":               stdlib.DistinctFunc,

From bfd1ea387722a0de6178085047596302c5535039 Mon Sep 17 00:00:00 2001
From: Anthony Poschen <zanven42@gmail.com>
Date: Mon, 26 Oct 2020 16:37:28 +1100
Subject: [PATCH 2/3] Added doco for conditonal tags in bake file.

Signed-off-by: Anthony Poschen <zanven42@gmail.com>
---
 README.md | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/README.md b/README.md
index 5550fcfe..0f4de262 100644
--- a/README.md
+++ b/README.md
@@ -741,6 +741,43 @@ $ docker buildx bake --print webapp
 }
 ```
 
+Example of only adding tags if a variable is not empty using an `notequal` function:
+
+```
+$ cat <<'EOF' > docker-bake.hcl
+variable "TAG" {default="" }
+
+group "default" {
+	targets = [
+    "webapp",
+  ]
+}
+
+target "webapp" {
+  context="."
+  dockerfile="Dockerfile"
+  tags = [
+      "my-image:latest",
+      notequal("",TAG) ? "my-image:${TAG}": "",
+  ]
+}
+EOF
+
+$ docker buildx bake --print webapp
+{
+   "target": {
+      "webapp": {
+         "context": ".",
+         "dockerfile": "Dockerfile",
+         "tags": [
+            "my-image:latest"
+         ]
+      }
+   }
+}
+```
+
+
 ### `buildx imagetools create [OPTIONS] [SOURCE] [SOURCE...]`
 
 Imagetools contains commands for working with manifest lists in the registry. These commands are useful for inspecting multi-platform build results.

From 5843e67a905c5c9c6a22f19f646fbe0b0db22997 Mon Sep 17 00:00:00 2001
From: Tonis Tiigi <tonistiigi@gmail.com>
Date: Mon, 7 Dec 2020 21:02:48 -0800
Subject: [PATCH 3/3] fix indentations in example

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
---
 README.md | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 0f4de262..768c9d3e 100644
--- a/README.md
+++ b/README.md
@@ -749,17 +749,17 @@ variable "TAG" {default="" }
 
 group "default" {
 	targets = [
-    "webapp",
-  ]
+		"webapp",
+	]
 }
 
 target "webapp" {
-  context="."
-  dockerfile="Dockerfile"
-  tags = [
-      "my-image:latest",
-      notequal("",TAG) ? "my-image:${TAG}": "",
-  ]
+	context="."
+	dockerfile="Dockerfile"
+	tags = [
+		"my-image:latest",
+		notequal("",TAG) ? "my-image:${TAG}": "",
+	]
 }
 EOF