windmill-labs/windmill · warning

Found ${collisions.length} path(s) that differ only by lette

Error message

Found ${collisions.length} path(s) that differ only by letter case:
${groups}
On case-insensitive filesystems (Windows, default macOS) these collapse into a single file/directory and cannot both be synced. Rename one side to a distinct path to make the tree sync reliably across platforms.

What it means

A warning from warnUnrepresentableCaseCollisions during sync. The remote workspace contains two or more paths that differ only by letter case (e.g. `Scripts/Foo` and `scripts/foo`). On a case-insensitive filesystem (Windows, default macOS) these collapse into one file, so both cannot be synced to disk; the user must rename one.

Source

Thrown at cli/src/commands/sync/sync.ts:2487

    const fromPrefix = fromSegs.slice(0, i + 1).join("/");
    const toPrefix = toSegs.slice(0, i + 1).join("/");
    const key = `${fromPrefix} -> ${toPrefix}`;
    if (!seen.has(key)) {
      seen.add(key);
      out.push(key);
    }
  }
  return out;
}

// Emit a single grouped warning for case-only collisions that cannot be
// represented on a case-insensitive filesystem (two distinct server paths
// differing only by case). Unlike the drift handled by
// canonicalizeCaseInsensitiveKeys, these require the user to rename one side.
function warnUnrepresentableCaseCollisions(collisions: string[][]): void {
  if (collisions.length === 0) return;
  const groups = collisions.map((g) => `  - ${g.join("  <->  ")}`).join("\n");
  log.warn(
    `Found ${collisions.length} path(s) that differ only by letter case:\n` +
      `${groups}\n` +
      `On case-insensitive filesystems (Windows, default macOS) these collapse ` +
      `into a single file/directory and cannot both be synced. Rename one side ` +
      `to a distinct path to make the tree sync reliably across platforms.`,
  );
}

// Probe (and cache) whether `dir` lives on a case-insensitive filesystem.
// Auto-detected by round-tripping a probe file under two casings, with an
// explicit WMILL_CASE_INSENSITIVE_FS=true/false override so Windows behaviour
// can be forced (or emulated for cross-platform repos / tests) on any host.
let _caseInsensitiveFsCache: boolean | undefined;
export async function isCaseInsensitiveFilesystem(
  dir: string,
): Promise<boolean> {
  const override = (process.env.WMILL_CASE_INSENSITIVE_FS ?? "")
    .trim()

View on GitHub (pinned to e474e8803c)

Solutions

1. Rename one of the colliding items on the server (via UI or `wmill` rename) so paths differ beyond case.
2. Re-run the sync; the warning disappears once no case-only collisions remain.
3. Prevent recurrence by adopting a naming convention (e.g. lowercase kebab-case paths) enforced in review/CI.
4. On macOS, if the files already collapsed locally, delete the merged directory and re-pull after fixing the server paths.

Example fix

// before: server has both
u/admin/hello_script.script/script
u/admin/Hello_Script.script/script
// after: rename one side
u/admin/hello_script.script/script
u/admin/hello_script_v2.script/script

const seen = new Map<string, string>();
for (const p of allRemotePaths) {
  const key = p.toLowerCase();
  if (seen.has(key)) throw new Error(`Case collision: ${seen.get(key)} <-> ${p}`);
  seen.set(key, p);
}

function hasCaseCollision(paths: string[]): boolean {
  const set = new Set(paths.map(p => p.toLowerCase()));
  return set.size !== paths.length;
}

if (hasCaseCollision(remotePaths)) {
  console.error("Rename one side on the server before pulling on case-insensitive OS");
} else {
  await wmill.sync.pull(...);
}

When it happens

Trigger: `wmill sync pull`/`push` detects, after diffing, remote item groups whose paths collide case-insensitively. Typical origin: items created by different people/automation with differing casing, or renames that only changed case.

Common situations: Team members on case-sensitive Linux created both paths; a rename on the server changed only letter case; duplicate scripts created with 'MyScript' vs 'myscript'; CI on Windows/macOS then fails or clobbers files when pulling.

Related errors

• Workspace folder not found, are you in the right directory?
• Error reading dir: ${localP}, ${e}
• File not found: ${filePath}
• Directory not found: ${targetDirectory}
• Path is not a directory: ${targetDirectory}

AI-assisted analysis of windmill-labs/windmill@e474e8803c (2026-09-03). Data as JSON: /api/errors/a517e04465d07633. Report an issue: GitHub.