Function copyPlanFile

src/node/utils/runtime/helpers.ts:238–266

(
  runtime: Runtime,
  sourceWorkspaceName: string,
  sourceWorkspaceId: string,
  targetWorkspaceName: string,
  projectName: string
)

 * Silently succeeds if source file doesn't exist at either location.
 */
export async function copyPlanFile(
  runtime: Runtime,
  sourceWorkspaceName: string,
  sourceWorkspaceId: string,
  targetWorkspaceName: string,
  projectName: string
): Promise<void> {
  const muxHome = runtime.getMuxHome();
  const sourcePath = getPlanFilePath(sourceWorkspaceName, projectName, muxHome);
  // Legacy paths only used for non-Docker runtimes
  const legacySourcePath = getLegacyPlanFilePath(sourceWorkspaceId);
  const targetPath = getPlanFilePath(targetWorkspaceName, projectName, muxHome);

  // Prefer the new layout, but fall back to the legacy layout.
  //
  // Note: we intentionally use runtime file I/O instead of `cp` because:
  // 1) bash doesn't expand ~ inside quotes
  // 2) the target per-project plan directory may not exist yet
  // 3) runtime.writeFile() already handles directory creation + tilde expansion
  for (const candidatePath of [sourcePath, legacySourcePath]) {
    try {
      const content = await readFileString(runtime, candidatePath);
      await writeFileString(runtime, targetPath, content);
      return;
    } catch {
      // Try next candidate
    }
  }
}

/**
 * Copy a plan file across runtimes (e.g., during fork where source/target may be