The preview command

dispat preview plans, then prints the pending release notes: the breaking-changes/features/fixes sections plus provider updates that the next release's changelog entry and GitHub release body would carry. It covers every package that has something pending, in publish order, narrowed by --package / --space / --group or the invocation folder. It follows the release-notes windowing, so a pending prerelease previews only its own changeset. Prints no pending changes when nothing is, naming the selection when there was one.

Choosing which body to preview

The two records are configured separately, so they can say different things. --changelog prints the changelog entry body and --github the GitHub release body, each under its own entry format: its own header, footer and releaseName. Together they print both under one header per package, labelled --- changelog --- and --- github release ---. Naming neither prints the changelog entry.

This is where you check what the channel filters actually do before releasing anything, since a preview renders for the channel the pending release is on.

Two things a preview cannot show. The ### Release block a GitHub body carries in commit mode is built from what publishing exported, and nothing has been published, so it is absent. And when a record would write nothing at all, the preview says so in its place:

## core@1.3.0-beta.0 (stable -> beta)

github release withheld: the channels do not admit beta

The reason is either disabled by config or the channels the record is restricted to. Whether a GitHub release is created also depends on the DISPAT_EXPORT_GITHUB export, which no preview can know; the note covers the configured policy, which is the part you can act on.

Flags

Beside the global flags:

Flag	Default	Effect
--changelog	false	Print the changelog entry body. The default when neither this nor --github is given.
--github	false	Print the GitHub release body, under the github entry format. Beside --changelog, both are printed and labelled.
--package, -p		Every package-selecting command (release, status, run, preview, changelog, autoversion, autowriter, autoreplacer, commit, github, compute): narrow to the named packages. Repeatable and comma-separated, matched case-insensitively, * globs (-p '*' is every package); see Choosing the packages.
--space, -s		The same eleven commands: narrow to every package of the named spaces, with the same spellings. A standalone package belongs to no space; see Choosing the packages.
--group, -g		The same eleven commands: narrow to every package of the named versioning groups, with the same spellings. A group is a versionGroups entry or a space that versions as one, so it may cross spaces; see Choosing the packages.