Shadcn Errors CLI Sync Mismatch

shadcn CLI Sync Mismatch : Recovering and Preventing Overwrite of Local Edits

shadcn copies component source into your repo. Once copied, the file in components/ui/<name>.tsx is YOUR code. The CLI does NOT remember that you edited it. Re-running shadcn add <name> --overwrite (or running add <name> with -y and accepting the prompt) replaces the file byte-for-byte with the current registry version. Local edits are gone. There is no undo inside the CLI ; recovery is git-only.

This skill defines the diff-first workflow that prevents that loss, three resolution strategies for picking up upstream changes, and the custom-variants-in-a-separate-file pattern that makes re-adds safe.

Companion skills :

• shadcn-core-cli : full reference for every CLI command and flag
• shadcn-impl-component-install : initial component installation flow
• shadcn-errors-styling-conflicts : when re-adds expose Tailwind class-order conflicts in your customizations

Quick Reference : The Problem in One Paragraph

components.json does NOT record which version of each component you have. The CLI is evergreen : every add fetches the CURRENT registry item. There is no per-component lockfile, no components.lock.json, no installedVersion field. The single source of truth for "what version do I have" is the file content on disk. If you edited that file and lost the prior commit, the only recovery is to re-add (which discards your edits) or restore from git history. ALWAYS treat every file in components/ui/ as code you own and version-control like any other source.

Quick Reference : The Diff-First Workflow (ALWAYS)

NEVER run add <name> --overwrite blind. ALWAYS preview with --diff first. The canonical sequence is :

1. git status MUST be clean (or all components/ui/ changes staged and committed). NO uncommitted edits to the target file.
2. pnpm dlx shadcn@latest add <name> --diff to preview the upstream diff against your current file.
3. Decide on a resolution strategy (see next section).
4. If applying : pnpm dlx shadcn@latest add <name> --overwrite.
5. git diff HEAD to review what the CLI changed.
6. Re-apply any necessary customizations (or rely on custom-variants-in-separate-file).
7. Commit with a message that names the registry version source (e.g. "chore: re-add Calendar from shadcn@latest for v9 fix").

If git status is dirty when you start, STOP. Commit or stash first. A failed merge plus a dirty tree means you cannot tell which lines are "your edit" and which are "shadcn just wrote that".

--dry-run is a safer-than---diff first probe : it prints the planned operations without writing anything AND without producing a patch. Use --dry-run to confirm what files will be touched, then --diff to see the actual content delta.

Quick Reference : The --diff Flag, NOT a diff Subcommand

There is no shadcn diff subcommand. The diff capability ships as a FLAG on the add command. Verified at https://ui.shadcn.com/docs/cli (2026-05-19) :

• pnpm dlx shadcn@latest add button --diff is correct.
• pnpm dlx shadcn@latest diff button is WRONG. It throws "unknown command".

There is also no shadcn update subcommand. The update workflow IS the diff + overwrite pair above.

Quick Reference : The Three Resolution Strategies

When --diff shows that upstream has changed, you choose ONE strategy per component. The choice is per-component, not per-project.

Most projects use a mix : Button and Card are vendored (rarely change), Calendar and Command are diff-merged (cmdk / react-day-picker break often), a heavily-extended Sidebar is forked to lib/components/sidebar/.

Strategy 1 : Vendor (treat add as a one-time snapshot)

ALWAYS run shadcn add <name> exactly once per component. Edit the file freely afterwards. NEVER re-run add <name> for that component. The registry version is irrelevant ; the on-disk version is canonical.

Trade-off : you stop receiving upstream bugfixes and security patches. For low-risk components (Card, Badge, Skeleton, Separator, Alert) this is fine. For components with active maintenance (Calendar, Command/Combobox, Sidebar, Sheet) the risk is real.

Mark vendored components with a top-of-file comment so the next maintainer knows :

// VENDORED 2026-05-15 from shadcn@latest. Do NOT re-run `shadcn add card`.
// Local edits below.

Strategy 2 : Diff-merge (recommended default)

You keep up with upstream AND retain customizations. Workflow :

1. Commit all local work to clean the tree.
2. pnpm dlx shadcn@latest add <name> --diff to see upstream changes.
3. If the diff is small (1-3 lines, no overlap with your edits) : apply with --overwrite, then re-apply your custom variant or prop in a follow-up commit.
4. If the diff overlaps your edits : do NOT use --overwrite. Instead, manually copy the upstream lines from the diff output and apply them in your editor with three-way reasoning (upstream / yours / merged).
5. Commit with subject "chore: sync with shadcn@latest" and body listing both upstream changes pulled and local changes preserved.

Diff-merge fails fastest when you have inline custom variants. See the "Custom Variants in a Separate File" pattern below for the fix.

Strategy 3 : Fork (copy upstream to a different path)

You treat the registry file as an upstream reference and maintain a forked copy at a different path that imports the same primitives.

pnpm dlx shadcn@latest add sidebar          # writes components/ui/sidebar.tsx
mkdir -p lib/components/sidebar
cp components/ui/sidebar.tsx lib/components/sidebar/sidebar.tsx
# Edit lib/components/sidebar/sidebar.tsx freely.
# Update imports : import { Sidebar } from "@/lib/components/sidebar/sidebar"

Keep the original components/ui/sidebar.tsx ONLY as a reference for diffs against upstream ; OR delete it if your fork is permanent. To pull upstream changes : add sidebar --overwrite updates the reference copy ; then diff lib/components/sidebar/sidebar.tsx components/ui/sidebar.tsx shows what to consider porting.

Trade-off : you lose the convention that @/components/ui/<name> points to the canonical component. Document the fork in a top-level README or a lib/components/README.md.

Quick Reference : The Custom-Variants-in-a-Separate-File Pattern

This pattern makes --overwrite safe. The rule : NEVER add a new variant value or size value to components/ui/<name>.tsx. ALWAYS put extensions in a sibling file.

// components/ui/button-extensions.tsx
import { cva, type VariantProps } from "class-variance-authority"
import { Button as BaseButton, buttonVariants as baseVariants } from "@/components/ui/button"
import { cn } from "@/lib/utils"

const extendedVariants = cva("", {
  variants: {
    intent: {
      warning: "bg-amber-500 text-amber-50 hover:bg-amber-600",
      success: "bg-emerald-600 text-emerald-50 hover:bg-emerald-700",
    },
  },
})

type Props = React.ComponentProps<typeof BaseButton> &
  VariantProps<typeof extendedVariants>

export function ExtButton({ intent, className, ...props }: Props) {
  return (
    <BaseButton
      className={cn(extendedVariants({ intent }), className)}
      {...props}
    />
  )
}

Now shadcn add button --overwrite is safe : button-extensions.tsx is untouched, the new warning and success intents survive.

The same pattern applies to forms (form-extensions.tsx), data tables (data-table-extensions.tsx), and any other component you commonly augment. See references/examples.md for full working code.

Quick Reference : Pre-Update Hygiene Checklist

Before ANY add <name> --overwrite or add <name> without -y :

• git status clean OR all components/ui/ edits committed.
• On a feature branch, not main. The merge should be a PR.
• pnpm dlx shadcn@latest add <name> --dry-run ran without error.
• pnpm dlx shadcn@latest add <name> --diff reviewed end-to-end.
• You can name the upstream change (bugfix? new prop? rename?). If you cannot, the update is not actionable yet.
• Custom variants live in a *-extensions.tsx file, NOT inline. If they are inline, refactor BEFORE the overwrite.

Quick Reference : Detection : Which Files Are CLI-Touched vs Custom

If you inherit a project and need to know which files the CLI wrote :

# All shadcn-managed component files (under components/ui/).
git log --diff-filter=A --name-only -- 'components/ui/*' \
  | grep -E '^components/ui/[a-z-]+\.tsx$' | sort -u

For deeper attribution, compare each file to the current registry version (cheap heuristic : if git log <file> shows a single commit with a "chore: add " message, it was likely never edited).

A custom file outside components/ui/ (e.g. lib/components/...) is unambiguously yours. A file inside components/ui/ with multiple commits and non-shadcn-shaped diffs has been customized.

Quick Reference : Migration Aids

shadcn ships migration commands that perform sweeping rewrites across all components/ui/ files. Two are relevant here because they explicitly touch every component file and therefore interact with the same overwrite hazard :

• pnpm dlx shadcn@latest migrate icons : swaps the project icon library (e.g. lucide-react -> @radix-ui/react-icons). Updates every component's icon imports. Run with clean tree. Set the new default in components.json#iconLibrary after.
• pnpm dlx shadcn@latest migrate radix : moves from per-primitive @radix-ui/react-* packages to the unified radix-ui package (Feb 2026 change). Rewrites all imports.
• pnpm dlx shadcn@latest migrate rtl : adds right-to-left support.

Pass -y to skip the per-file confirmation prompt only after a --dry-run review. Both migrate icons and migrate radix are SAFE for vendored components in the sense that they only touch imports, not body logic, BUT they still rewrite the file, so commit first.

See references/methods.md for command signatures and references/examples.md for full workflows.

Decision Tree : Should I Re-Run shadcn add <name>?

Is there an upstream change you NEED (bugfix, security, breaking-deps fix)?
├── No  -> Do nothing. The current file is fine.
└── Yes -> Continue.
        Is the local file edited beyond what `add` originally wrote?
        ├── No  -> `add <name> --overwrite`. Done.
        └── Yes -> Are custom variants in a `*-extensions.tsx` sibling file?
                ├── Yes -> `add <name> --overwrite` is safe. The
                │          extensions file is untouched.
                └── No  -> STOP. Refactor inline variants into
                           `*-extensions.tsx` FIRST. Then overwrite.
                           OR use diff-merge (manual three-way merge).
                           OR fork to `lib/components/` if customization
                           is heavy enough.

Patterns : What to Document Per Component

For every component in components/ui/, the project SHOULD record one of these states. A single comment line at the top of the file or in components/ui/README.md is enough :

• VENDORED YYYY-MM-DD : never re-add. Living snapshot.
• TRACKED : will run add --diff before any update.
• FORKED-TO <path> : original kept as upstream reference, real code lives elsewhere.
• MIGRATED-AWAY : replaced with a non-shadcn alternative.

Without this state, the next developer cannot tell whether overwriting is safe.

Reference Links

• Companion : shadcn-core-cli (full CLI reference including all add flags)
• Companion : shadcn-impl-component-install (initial install workflow)
• Companion : shadcn-errors-styling-conflicts (post-overwrite Tailwind class-order issues)
• Detailed methods : references/methods.md
• Worked examples : references/examples.md
• Anti-patterns to avoid : references/anti-patterns.md
• Official CLI docs : https://ui.shadcn.com/docs/cli
• Official components.json schema : https://ui.shadcn.com/docs/components-json