feat(config): Add fingerprint ignore tags to some config fields by dmcilvaney · Pull Request #46 · microsoft/azure-linux-dev-tools

dmcilvaney · 2026-03-31T00:52:37Z

Prepare for fingerprint calculations in #47

Copilot

Pull request overview

This PR introduces a fingerprint:"-" struct tag on selected internal/projectconfig fields to mark them as excluded from “component fingerprinting”, and adds a test to ensure the exclusion list stays consistent over time.

Changes:

Add fingerprint:"-" tags to multiple config fields that are intended to be treated as non-build-input metadata.
Add a reflection-based unit test to detect accidental additions/removals of fingerprint:"-" exclusions.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
internal/projectconfig/overlay.go	Excludes `ComponentOverlay.Description` from the fingerprint via tag.
internal/projectconfig/build.go	Excludes check/failure/hints “reason/policy” fields from the fingerprint via tag.
internal/projectconfig/component.go	Excludes bookkeeping/back-reference fields and `SourceFileReference.Origin` from the fingerprint via tag.
internal/projectconfig/distro.go	Excludes `DistroReference.Snapshot` from the fingerprint via tag.
internal/projectconfig/fingerprint_test.go	Adds a test that asserts the expected set of fingerprint exclusions.

internal/projectconfig/build.go

Copilot · 2026-03-31T01:01:13Z

internal/projectconfig/component.go


 	// Origin for this source file. When omitted, the file is resolved via the lookaside cache.
-	Origin Origin `toml:"origin,omitempty" json:"origin,omitempty"`
+	Origin Origin `toml:"origin,omitempty" json:"origin,omitempty" fingerprint:"-"`


Excluding SourceFileReference.Origin from the fingerprint assumes the source file’s content is fully captured by Filename + Hash/HashType, but hash/hash-type are optional and downloads proceed without validation when they’re empty (see downloadAndValidate in internal/providers/sourceproviders/sourcemanager.go). If the fingerprint is used to decide whether sources/build outputs are up-to-date, consider including Origin when hash info is missing, or enforce that hash + hash-type are required for source-files entries so changes in origin can’t silently change inputs without changing the fingerprint.

Suggested change

Origin Origin `toml:"origin,omitempty" json:"origin,omitempty" fingerprint:"-"`

Origin Origin `toml:"origin,omitempty" json:"origin,omitempty"`

Good point.

Will add a check to the calculation step that errors on this case

https://github.com/microsoft/azure-linux-dev-tools/pull/47/changes#diff-cce5a25e8082b983d1bd95b1e6b76967982f34152b25200002cf4a591838869dR78

Copilot · 2026-03-31T01:01:13Z

internal/projectconfig/distro.go

 	Version string `toml:"version,omitempty" json:"version,omitempty" jsonschema:"title=Version,description=Version of the referenced distro"`
 	// Snapshot date/time for source code if specified components will use source as it existed at this time.
-	Snapshot string `toml:"snapshot,omitempty" json:"snapshot,omitempty" jsonschema:"format=date-time,title=Snapshot,description=If specified use source code as it existed at this date/time"`
+	Snapshot string `toml:"snapshot,omitempty" json:"snapshot,omitempty" jsonschema:"format=date-time,title=Snapshot,description=If specified use source code as it existed at this date/time" fingerprint:"-"`


DistroReference.Snapshot directly affects which upstream commit is checked out when upstream-commit isn’t set (see checkoutTargetCommit in internal/providers/sourceproviders/fedorasourceprovider.go). Ignoring snapshot in the fingerprint can therefore miss real input changes when the snapshot time changes. If you intend to keep snapshot out of the fingerprint, the resolved commit hash used for the checkout should be captured elsewhere and included in the fingerprint/state instead.

Suggested change

Snapshot string `toml:"snapshot,omitempty" json:"snapshot,omitempty" jsonschema:"format=date-time,title=Snapshot,description=If specified use source code as it existed at this date/time" fingerprint:"-"`

Snapshot string `toml:"snapshot,omitempty" json:"snapshot,omitempty" jsonschema:"format=date-time,title=Snapshot,description=If specified use source code as it existed at this date/time"`

The fully resolved commit for each component is part of the fingerprint. That is more reliable than the snapshot date (also, updating the snapshot date would cause a rebuild of every single package, even if many of them didn't change).

https://github.com/microsoft/azure-linux-dev-tools/pull/45/changes#diff-5ae28c7eb8f561698b82c99c0886efc356c096d562ed3fd66a915fd47d10a8b8R246

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

internal/projectconfig/fingerprint_test.go

Copilot

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

dmcilvaney · 2026-04-02T00:40:39Z

Should add a blurb in copilot instructions about the fingerprint tag.

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

.github/instructions/go.instructions.md

dmcilvaney · 2026-04-02T15:59:16Z

Test failure looks transient and unrelated to changes

In preparation for the upcoming component change detection feature, this commit selects which config fields should be ignored when computing the identity of a component using a fingerprinting mechanism.

reubeno · 2026-04-03T15:23:40Z

internal/projectconfig/package.go

 type PackageConfig struct {
 	// Publish holds the publish settings for this package.
-	Publish PackagePublishConfig `toml:"publish,omitempty" json:"publish,omitempty" jsonschema:"title=Publish settings,description=Publishing settings for this binary package"`
+	Publish PackagePublishConfig `toml:"publish,omitempty" json:"publish,omitempty" jsonschema:"title=Publish settings,description=Publishing settings for this binary package" fingerprint:"-"`


Are we sure about this one? I understand it doesn't affect the generated package, but how would we change where something is published to and have the re-publishing happen?

I asked a few folks about this one, consensus was do not track. Once a binary is "built" it should just be moved/retagged etc. I'd assume?

reubeno · 2026-04-03T15:25:14Z

.github/instructions/go.instructions.md

    }
    ```

+## Component Fingerprinting — `fingerprint:"-"` Tags


Can we get a general overview of this new tag added to some of the human-targeted docs too?

Final PR has a section on it, figured I'd put the whole feature set in a doc.

Copilot AI review requested due to automatic review settings March 31, 2026 00:52

Copilot started reviewing on behalf of dmcilvaney March 31, 2026 00:53 View session

dmcilvaney mentioned this pull request Mar 31, 2026

feat(component): Add component change detection #42

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dmcilvaney marked this pull request as draft March 31, 2026 01:41

dmcilvaney force-pushed the damcilva/component_change_detection_parts/4 branch from daeff90 to 33ef430 Compare April 1, 2026 23:02

dmcilvaney marked this pull request as ready for review April 1, 2026 23:02

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dmcilvaney commented Apr 1, 2026

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.github/instructions/go.instructions.md Show resolved Hide resolved

feat(config): Add fingerprint ignore tags to some config fields

44142f2

In preparation for the upcoming component change detection feature, this commit selects which config fields should be ignored when computing the identity of a component using a fingerprinting mechanism.

dmcilvaney force-pushed the damcilva/component_change_detection_parts/4 branch from d298954 to 44142f2 Compare April 2, 2026 16:07

reubeno reviewed Apr 3, 2026

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	Origin Origin `toml:"origin,omitempty" json:"origin,omitempty" fingerprint:"-"`
	Origin Origin `toml:"origin,omitempty" json:"origin,omitempty"`

	Snapshot string `toml:"snapshot,omitempty" json:"snapshot,omitempty" jsonschema:"format=date-time,title=Snapshot,description=If specified use source code as it existed at this date/time" fingerprint:"-"`
	Snapshot string `toml:"snapshot,omitempty" json:"snapshot,omitempty" jsonschema:"format=date-time,title=Snapshot,description=If specified use source code as it existed at this date/time"`

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dmcilvaney commented Mar 31, 2026 •

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