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## Output
```text
Using the global ARGs with default values should produce a valid build.
```
## Description
An `ARG` used in an image reference should be valid when no build arguments are used. An image build should not require `--build-arg` to be used to produce a valid build.
## Examples
❌ Bad: don't rely on an ARG being set for an image reference to be valid
```dockerfile
ARG TAG
FROM busybox:${TAG}
```
✅ Good: include a default for the ARG
```dockerfile
ARG TAG=latest
FROM busybox:${TAG}
```
✅ Good: ARG can be empty if the image would be valid with it empty
```dockerfile
ARG VARIANT
FROM busybox:stable${VARIANT}
```
✅ Good: Use a default value if the build arg is not present
```dockerfile
ARG TAG
FROM alpine:${TAG:-3.14}
```
|
