feat(copy): Support copying artifacts across multiple platforms. by hellocn9 · Pull Request #1954 · oras-project/oras

hellocn9 · 2026-01-08T14:57:45Z

What this PR does / why we need it:
In certain scenarios, only the images for the linux/amd64 and linux/arm64 platforms need to be synchronized. However, in the current version, if --platform is not specified, images for all platforms are synchronized; whereas when -- platform is specified, only a single platform architecture can be provided. To address this issue, this PR introduces support for specifying multiple platform architectures with --platform, separated by commas.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #1945

Please check the following list:

Does the affected code have corresponding tests, e.g. unit test, E2E test?
Does this change require a documentation update?
Does this introduce breaking changes that would require an announcement or bumping the major version?
Do all new files have an appropriate license header?

wangxiaoxuan273 · 2026-01-09T02:25:30Z

@shizhMSFT @FeynmanZhou Can you take a look?

FeynmanZhou · 2026-01-09T04:39:22Z

Thanks @hellocn9 for the contribution! Are you looking to resolve this issue in this PR? #1945

Copilot

Pull request overview

This PR adds support for copying artifacts across multiple platforms by allowing users to specify comma-separated platform architectures with the --platform flag (e.g., --platform linux/amd64,linux/arm64,linux/arm/v7). Previously, only a single platform could be specified at a time.

Key changes:

Extended platform parsing to support comma-separated lists of platforms
Added new copyMultiplePlatforms function to handle copying filtered manifests from indexes
Implemented platform matching logic to filter index manifests based on specified platforms

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 14 comments.

File	Description
cmd/oras/internal/option/platform.go	Added `Platforms` field to support multiple platforms, updated parsing logic to handle comma-separated platform strings, and refactored single platform parsing into a separate method
cmd/oras/root/cp.go	Added import for metadata handler, updated documentation with multi-platform example, implemented `copyMultiplePlatforms` function with index filtering and platform matching logic

Comments suppressed due to low confidence (1)

cmd/oras/internal/option/platform.go:126

The parseSinglePlatform function doesn't populate the Platforms slice when a single platform is parsed. This creates inconsistency where Platform is set but Platforms remains nil/empty. This could cause issues in code that checks len(opts.Platform.Platforms) > 0 to determine if platforms were specified. For a single platform, the code at line 146 in cp.go would evaluate to false even when a platform is specified.

func (opts *Platform) parseSinglePlatform(platformStr string) error {
	// OS[/Arch[/Variant]][:OSVersion]
	// If Arch is not provided, will use GOARCH instead
	var platformPart string
	var p ocispec.Platform
	platformPart, p.OSVersion, _ = strings.Cut(platformStr, ":")
	parts := strings.Split(platformPart, "/")
	switch len(parts) {
	case 3:
		p.Variant = parts[2]
		fallthrough
	case 2:
		p.Architecture = parts[1]
	case 1:
		p.Architecture = runtime.GOARCH
	default:
		return fmt.Errorf("failed to parse platform %q: expected format os[/arch[/variant]]", platformStr)
	}
	p.OS = parts[0]
	if p.OS == "" {
		return fmt.Errorf("invalid platform: OS cannot be empty")
	}
	if p.Architecture == "" {
		return fmt.Errorf("invalid platform: Architecture cannot be empty")
	}
	opts.Platform = &p
	return nil
}

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cmd/oras/internal/option/platform.go

cmd/oras/root/cp.go

hellocn9 · 2026-01-10T12:08:03Z

Thanks @hellocn9 for the contribution! Are you looking to resolve this issue in this PR? #1945

Yes, this PR addresses #1945. Thanks for reviewing!

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Signed-off-by: hellocn9 <zhangyancn9@126.com>

shizhMSFT

Besides above comments, please add related unit tests and E2E tests.

cmd/oras/internal/option/platform.go

cmd/oras/root/cp.go

…form filtering and error handling Signed-off-by: hellocn9 <zhangyancn9@126.com>

…opying Signed-off-by: hellocn9 <zhangyancn9@126.com>

hellocn9 · 2026-01-18T09:00:54Z

Besides above comments, please add related unit tests and E2E tests.

Done! Added unit & E2E tests for all platform-related changes.

hellocn9 · 2026-01-18T09:02:15Z

@shizhMSFT I’ve addressed all your feedback — please take a look when you have time!

cmd/oras/internal/option/platform.go

cmd/oras/root/cp.go

…form filtering Signed-off-by: hellocn9 <zhangyancn9@126.com>

TerryHowe · 2026-03-04T11:20:33Z

cmd/oras/root/cp.go

+	// Variant: optional; if specified, must match exactly, otherwise it is ignored
+	//if targetPlatform.Variant == "" && manifestPlatform.Variant != "" {
+	//	return false
+	//}


Suggested change

// Variant: optional; if specified, must match exactly, otherwise it is ignored

//if targetPlatform.Variant == "" && manifestPlatform.Variant != "" {

// return false

//}

cmd/oras/root/cp.go

TerryHowe · 2026-03-04T11:34:08Z

cmd/oras/root/cp.go

 	statusHandler, metadataHandler := display.NewCopyHandler(opts.Printer, opts.TTY, dst)

+	// Check if multiple platforms are specified
+	if len(opts.Platform.Platforms) > 1 && !opts.recursive {


This part is confusing me here, why is this checking for not recursive? If there are multiple platforms specified don't we want to copy the multiple platforms?

TerryHowe · 2026-03-04T11:36:29Z

cmd/oras/internal/option/platform.go

 		opts.FlagDescription = "request platform"
 	}
-	fs.StringVarP(&opts.platform, "platform", "", "", opts.FlagDescription+" in the form of `os[/arch][/variant][:os_version]`")
+	fs.StringSliceVarP(&opts.platform, "platform", "", nil, opts.FlagDescription+" in the form of `os[/arch][/variant][:os_version]` or comma-separated list for multiple platforms (supported in oras cp only)")


Unrelated to this PR, but that bit about "supported in oras cp only" is a good argument for composition over inheritance

TerryHowe · 2026-03-04T11:37:58Z

cmd/oras/internal/option/platform.go

 func (opts *ArtifactPlatform) ApplyFlags(fs *pflag.FlagSet) {
 	opts.FlagDescription = "set artifact platform"
-	fs.StringVarP(&opts.platform, "artifact-platform", "", "", "[Experimental] "+opts.FlagDescription+" in the form of `os[/arch][/variant][:os_version]`")
+	fs.StringSliceVarP(&opts.platform, "artifact-platform", "", nil, "[Experimental] "+opts.FlagDescription+" in the form of `os[/arch][/variant][:os_version]`")


Why was this changed?

TerryHowe · 2026-03-04T11:39:32Z

cmd/oras/root/cp.go

+	}
+
+	// Push the new index to the destination
+	if err = dst.Push(ctx, newIndexDesc, strings.NewReader(string(newIndexContent))); err != nil {


Suggested change

if err = dst.Push(ctx, newIndexDesc, strings.NewReader(string(newIndexContent))); err != nil {

if err = dst.Push(ctx, newIndexDesc, bytes.NewReader(newIndexContent)); err != nil {

hellocn9 requested review from TerryHowe, Wwwsylvia, sajayantony and shizhMSFT as code owners January 8, 2026 14:57

hellocn9 force-pushed the main branch from ec60c00 to b8f9f94 Compare January 8, 2026 15:06

FeynmanZhou requested a review from Copilot January 9, 2026 04:39

Copilot started reviewing on behalf of FeynmanZhou January 9, 2026 04:39 View session

Copilot AI reviewed Jan 9, 2026

View reviewed changes

feat(copy): Support copying artifacts across multiple platforms.

842629d

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Signed-off-by: hellocn9 <zhangyancn9@126.com>

hellocn9 force-pushed the main branch from 38c452f to 842629d Compare January 11, 2026 03:16

polarathene mentioned this pull request Jan 11, 2026

Support multiple --platform where appropriate #1945

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1 task

shizhMSFT requested changes Jan 17, 2026

View reviewed changes

hellocn9 added 2 commits January 18, 2026 16:04

refactor(copy): Optimize platform copying logic to support multi-plat…

bd5a7b0

…form filtering and error handling Signed-off-by: hellocn9 <zhangyancn9@126.com>

test(copy): add related unit tests and E2E tests for multi-platform c…

8b9cbc3

…opying Signed-off-by: hellocn9 <zhangyancn9@126.com>

hellocn9 requested a review from shizhMSFT January 18, 2026 09:03

shizhMSFT reviewed Jan 18, 2026

View reviewed changes

hellocn9 requested a review from shizhMSFT January 20, 2026 09:22

refactor(copy): Optimize platform copying logic to support multi-plat…

70e0d23

…form filtering Signed-off-by: hellocn9 <zhangyancn9@126.com>

hellocn9 force-pushed the main branch from 1e7c7d1 to 70e0d23 Compare January 20, 2026 09:45

TerryHowe requested changes Mar 4, 2026

View reviewed changes

	if err = dst.Push(ctx, newIndexDesc, strings.NewReader(string(newIndexContent))); err != nil {
	if err = dst.Push(ctx, newIndexDesc, bytes.NewReader(newIndexContent)); err != nil {

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hellocn9 commented Jan 10, 2026

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hellocn9 commented Jan 18, 2026

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hellocn9 commented Jan 8, 2026 •

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