Failure when multiple projects exist

Metadata

Source

tuist/once #258

Updated

Sep 3, 2026

Details

Problem

Once cannot inspect an Xcode repository without creating once.toml when the repository contains multiple .xcodeproj files.

This conflicts with the documented zero-manifest adoption flow for existing Xcode projects.

Environment

Once 0.50.0
macOS
Xcode 26.5

Reproduction

Given a repository containing:

App.xcodeproj
App.xcworkspace
Several nested demo/tool .xcodeproj files

Run:

once query targets

Once fails with:

☁  $ once query targets
2026-09-03T18:11:26.206696Z ERROR once: session failed session_id=01a06877-ec3e-74e0-b389-9de79a390771 error=loading graph
once: evaluation error in xcode:
target kind resolver failed for `xcode`: Traceback (most recent call last):
File <builtin>, in <module>
* once//modules/all.star:18623, in _xcode_workspace_resolver
    entry_path = _xcode_project_path(ctx)
* once//modules/all.star:15294, in _xcode_project_path
    fail(ctx["label"]["id"] + ": multiple Xcode projects found; set the `project`...
error: fail: xcode: multiple Xcode projects found; set the `project` attribute to one of: App.xcodeproj/project.pbxproj, Modules/Metrics/App/MetricsApp.xcodeproj/project.pbxproj, Modules/ContentModeration/ContentModerationDemo/ContentModerationDemo.xcodeproj/project.pbxproj, Modules/Mosaic/Apps/DesignSystem.xcodeproj/project.pbxproj, Modules/PurchaseKit/PurchaseKitPlayground/PurchaseKitPlayground/PurchaseKitPlayground.xcodeproj/project.pbxproj
   --> once//modules/all.star:15294:9
    |
15294 |         fail(ctx["label"]["id"] + ": multiple Xcode projects found; set the `project` attribute to one of: " + ", ".join(candidates))
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |

while loading graph

Expected behavior

Would be nice if there was a CLI option for selecting the Xcode project or workspace without requiring a manifest, for example:

once query targets --project App.xcworkspace

or:

once native show xcode --path . --project App.xcworkspace

Motivation

Repositories commonly contain nested demo apps, development tools, package examples, and test projects.

Requiring once.toml solely to resolve this ambiguity adds friction to the “try Once against an existing Xcode project” workflow. The error already identifies the valid candidates, but there is currently no command-line repair.

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Comments

M

mamouneyya Sep 3, 2026

Note that the agent’s clever workaround was to create a once.toml manifest at the root:

[workspace]
include = ["once.toml"]

[[target]]
name = "app"
kind = "xcode_workspace"
srcs = [
  "App.xcworkspace/contents.xcworkspacedata",
  "App.xcworkspace/xcshareddata/swiftpm/Package.resolved",
  "App.xcodeproj/project.pbxproj",
  "App.xcodeproj/xcshareddata/xcschemes/*.xcscheme",
  "Modules/Mosaic/Apps/DesignSystem.xcodeproj/project.pbxproj",
  "BuildSettings/**/*.xcconfig",
  "Dependencies/Package.swift",
]

[target.attrs]
project = "App.xcworkspace"