Debug Tuist Project Issue
Quick Start
- Ask the user to describe the issue and the project setup (targets, dependencies, configurations, platform).
- Confirm the issue exists with the latest release by running
mise exec tuist@latest -- tuist generate
- If confirmed, clone the Tuist repository and build from source to test against main.
- Triage: fix the bug and open a PR, advise on misconfiguration, or recommend the user files an issue with a reproduction.
Step 1: Gather Context
Ask the user for:
- What command they ran (e.g. )
- The error message or unexpected behavior
- When the issue happens: generation time, compile time, or runtime (app launch or later)
- Their project structure: targets, platforms, dependencies (SwiftPM, XCFrameworks, local packages)
- Their and content (or relevant excerpts)
- Their Tuist version ()
The answer to "when" determines the verification strategy:
- Generation time: the issue might be a Tuist bug or a project misconfiguration. Reproduce with .
- Compile time: the generated project has incorrect build settings, missing sources, or wrong dependency wiring. Reproduce with after generation.
- Runtime: the app builds but crashes or misbehaves on launch or during use. Reproduce by installing and launching on a simulator.
Step 2: Reproduce with the latest release
Before investigating the source code, confirm the issue is not already fixed in the latest release.
Set up a temporary reproduction project
bash
REPRO_DIR=$(mktemp -d)
cd "$REPRO_DIR"
Create minimal
,
, and source files that reproduce the user's scenario. Keep it as small as possible while still triggering the issue.
Run generation with the latest Tuist release
bash
mise exec tuist@latest -- tuist generate --no-open --path "$REPRO_DIR"
If the issue involves dependencies, install them first:
bash
mise exec tuist@latest -- tuist install --path "$REPRO_DIR"
Check the result
- If generation succeeds and the issue is gone, tell the user to update to the latest version.
- If the issue persists, continue to Step 3.
Step 3: Build Tuist from Source
Clone the repository and build the
executable and
library from source to test against the latest code on
.
bash
TUIST_SRC=$(mktemp -d)
git clone --depth 1 https://github.com/tuist/tuist.git "$TUIST_SRC"
cd "$TUIST_SRC"
swift build --product tuist --product ProjectDescription --replace-scm-with-registry
The built binary will be at
. Use it to test the reproduction project:
bash
"$TUIST_SRC/.build/debug/tuist" generate --no-open --path "$REPRO_DIR"
If the issue is fixed on main
Tell the user the fix is already on
, and it hasn't been released, tell them it'll be in the nest release and point them to the relevant commit if you can identify it.
If the issue persists on main
Continue to Step 4.
Step 4: Triage the Issue
Investigate the Tuist source code to understand why the issue occurs.
Outcome A: It is a bug
- Identify the root cause in the source code.
- Apply the fix.
- Verify by rebuilding and running against the reproduction project:
bash
cd "$TUIST_SRC"
swift build --product tuist --product ProjectDescription --replace-scm-with-registry
"$TUIST_SRC/.build/debug/tuist" generate --no-open --path "$REPRO_DIR"
- Zip the reproduction project and include it in the PR:
bash
cd "$REPRO_DIR" && cd ..
zip -r reproduction.zip "$(basename "$REPRO_DIR")" -x '*.xcodeproj/*' -x '*.xcworkspace/*' -x 'Derived/*' -x '.build/*'
- Open a PR on the Tuist repository with:
- The fix
- The zipped reproduction project attached or committed as a fixture
- A clear description of the root cause and how to verify the fix
Outcome B: It is a misconfiguration
Tell the user what is wrong and how to fix it. Common misconfigurations:
- Missing before when using external dependencies
- Incorrect source or resource globs that exclude or double-include files
- Mismatched build configurations between the project and external dependencies
- Wrong product types for dependencies (static vs dynamic)
- Missing linker flag for Objective-C dependencies
- Using and globs together with
Provide the corrected manifest snippet so the user can apply the fix directly.
Outcome C: Unclear or needs team input
If you cannot determine whether it is a bug or misconfiguration, recommend the user:
- Open a GitHub issue at https://github.com/tuist/tuist/issues with:
- The reproduction project (zipped)
- The error output
- Their Tuist version and environment details
Provide a summary of what you investigated and what you ruled out, so the user does not have to repeat the triage.
Build Verification
When testing a fix, always verify the full cycle:
bash
# Build the patched tuist
cd "$TUIST_SRC"
swift build --product tuist --product ProjectDescription --replace-scm-with-registry
# Install dependencies if needed
"$TUIST_SRC/.build/debug/tuist" install --path "$REPRO_DIR"
# Generate the project
"$TUIST_SRC/.build/debug/tuist" generate --no-open --path "$REPRO_DIR"
# Build the generated project
xcodebuild build \
-workspace "$REPRO_DIR"/*.xcworkspace \
-scheme <scheme> \
-destination "platform=iOS Simulator,name=iPhone 16 Pro"
Runtime Verification
When the user reports a runtime issue (crash on launch, missing resources at runtime, wrong bundle structure, or unexpected behavior), you must go beyond building and actually launch the app on a simulator.
Launch and monitor for crashes
bash
# Boot a simulator
xcrun simctl boot "iPhone 16 Pro" 2>/dev/null || true
# Build for the simulator
xcodebuild build \
-workspace "$REPRO_DIR"/*.xcworkspace \
-scheme <scheme> \
-destination "platform=iOS Simulator,name=iPhone 16 Pro" \
-derivedDataPath "$REPRO_DIR/DerivedData"
# Install the app
xcrun simctl install booted "$REPRO_DIR/DerivedData/Build/Products/Debug-iphonesimulator/<AppName>.app"
# Launch and monitor — this will print crash info if the app terminates abnormally
xcrun simctl launch --console-pty booted <bundle-identifier>
The
flag streams the app's stdout/stderr so you can observe logs and crash output directly. Watch for:
- Immediate crash on launch: usually a missing framework, wrong bundle ID, missing entitlements, or stripped ObjC categories ( linker flag missing)
- Crash after a few seconds: often missing resources (images, storyboards, XIBs, asset catalogs) or a bundle structure mismatch
- Runtime misbehavior without crash: wrong resource paths, missing localization files, or incorrect Info.plist values
Check crash logs
If the app crashes without useful console output, pull the crash log:
bash
# List recent crash logs for the app
find ~/Library/Logs/DiagnosticReports -name "<AppName>*" -newer "$REPRO_DIR" -print
Read the crash log to identify the crashing thread and the faulting symbol.
Done Checklist
- Gathered enough context from the user to reproduce the issue
- Determined whether the issue is at generation time, compile time, or runtime
- Confirmed whether the issue exists in the latest release
- Tested against Tuist built from source (main branch)
- If runtime issue: launched the app on a simulator and verified the crash or misbehavior
- Triaged the issue as a bug, misconfiguration, or unclear
- If bug: applied fix, verified it, and opened a PR with reproduction project
- If misconfiguration: provided corrected manifest to the user
- If unclear: gave the user a summary and recommended next steps