GoogleContainerTools/skaffold · error

constructing inferred sync map: %w

Error message

constructing inferred sync map: %w

What it means

For artifacts with inferred file sync (sync.infer patterns), CheckArtifacts times constructing the sync map via sync.SyncMap. If it fails with an error other than build.ErrSyncMapNotSupported, this wrapped error is returned.

Source

Thrown at pkg/skaffold/diagnose/diagnose.go:79

			timeDeps1, deps, err := timeToListDependencies(ctx, artifact, tag, cfg)
			if err != nil {
				return fmt.Errorf("listing artifact dependencies: %w", err)
			}
			timeDeps2, _, err := timeToListDependencies(ctx, artifact, tag, cfg)
			if err != nil {
				return fmt.Errorf("listing artifact dependencies: %w", err)
			}

			fmt.Fprintln(out, " - Dependencies:", len(deps), "files")
			fmt.Fprintf(out, " - Time to list dependencies: %v (2nd time: %v)\n", timeDeps1, timeDeps2)

			// Only check sync map if inferred sync is configured on artifact
			if artifact.Sync != nil && len(artifact.Sync.Infer) > 0 {
				timeSyncMap1, err := timeToConstructSyncMap(ctx, artifact, cfg)
				if err != nil {
					if _, isNotSupported := err.(build.ErrSyncMapNotSupported); !isNotSupported {
						return fmt.Errorf("constructing inferred sync map: %w", err)
					}
				}
				timeSyncMap2, err := timeToConstructSyncMap(ctx, artifact, cfg)
				if err != nil {
					if _, isNotSupported := err.(build.ErrSyncMapNotSupported); !isNotSupported {
						return fmt.Errorf("constructing inferred sync map: %w", err)
					}
				} else {
					fmt.Fprintf(out, " - Time to construct sync map: %v (2nd time: %v)\n", timeSyncMap1, timeSyncMap2)
				}
			}

			timeMTimes1, err := timeToComputeMTimes(deps)
			if err != nil {
				return fmt.Errorf("computing modTimes: %w", err)
			}
			timeMTimes2, err := timeToComputeMTimes(deps)
			if err != nil {

View on GitHub (pinned to a1189de023)

Solutions

1. Check the wrapped error for the specific sync map construction failure
2. Validate sync.infer patterns are well-formed globs relative to the workspace
3. If the builder does not support inferred sync, switch to manual sync (manual section) or remove sync.infer
4. Update skaffold to the latest version, older builders may report unsupported sync incorrectly

Example fix

// before: builder without infer support
build:
  artifacts:
    - image: app
      custom:
        buildCommand: ./build.sh
      sync:
        infer: ['**/*.js']
// after: use manual sync
      sync:
        manual:
          - src: '**/*.js'
            dest: .

if artifact.Sync != nil && len(artifact.Sync.Infer) > 0 {
	for _, p := range artifact.Sync.Infer {
		if _, err := filepath.Match(p, ""); err != nil {
			return fmt.Errorf("invalid infer pattern %q: %w", p, err)
		}
	}
}

var errSyncNotSupported build.ErrSyncMapNotSupported
func isSyncNotSupported(err error) bool { return errors.As(err, &errSyncNotSupported) }

err := CheckArtifacts(ctx, cfg, tags, out)
var ns build.ErrSyncMapNotSupported
if err != nil && strings.Contains(err.Error(), "constructing inferred sync map") && !errors.As(err, &ns) {
	log.Warnf("sync map construction failed: %v", err)
}

When it happens

Trigger: Running `skaffold diagnose` on an artifact with `sync.infer` patterns where sync.SyncMap fails — e.g. a builder that doesn't support inferred sync returning an unexpected error, or invalid infer patterns.

Common situations: Using sync.infer with a builder lacking sync map support that returns a non-ErrSyncMapNotSupported error; malformed glob patterns in sync.infer; dockerfile changes not reflected in sync configuration.

Related errors

• didn't sync any files
• computing the size of the Docker context: %w
• getting tag for image %s
• listing artifact dependencies: %w
• computing modTimes: %w

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/e8de462990577420. Report an issue: GitHub.