Version conflicts happen when two dependencies demand incompatible versions of the same package. This guide explains how SPM resolution works and gives a practical playbook for diagnosing and fixing dependency clashes.
A version conflict occurs when SPM cannot find a single set of versions that satisfies every dependency's requirements at the same time.
This usually arises with a shared transitive dependency. Suppose package A requires a shared library within one version range and package B requires it within a non-overlapping range.
Since SPM must pick one version of that shared library for the whole build, and no version fits both ranges, resolution fails with a conflict.
The more dependencies you add, and the deeper their own dependency trees go, the higher the chance that two of them disagree about a common package.
Understanding that SPM resolves one version per package across the entire graph is the key mental model for fixing these clashes efficiently rather than by trial and error.
SPM uses semantic versioning to reason about compatibility. Versions are expressed as major, minor, and patch numbers, and the major number signals breaking changes.
When you declare a rule like 'up to next major version,' you are telling SPM that any version below the next major is acceptable for you.
During resolution, SPM gathers every constraint, from your direct dependencies and from their transitive dependencies, and searches for a combination that satisfies them all.
If such a combination exists, it records the chosen versions in Package.resolved. If not, it reports a conflict and names the packages and ranges involved.
Because the algorithm needs overlapping ranges, conflicts are fundamentally about incompatible constraints. Your job when fixing one is to create an overlap where none currently exists, either by changing your rules or by updating the packages that impose the conflicting ranges.
SPM's conflict output can look intimidating, but it contains the exact information you need. Slow down and read it.
The message typically states which packages depend on the shared package and what version ranges each requires. Those named ranges are the heart of the conflict.
Identify the shared package that everyone disagrees about, and note the specific ranges. Write them down if it helps you visualize where they fail to overlap.
Also note which of your direct dependencies pull in each conflicting requirement. Sometimes a single outdated direct dependency is responsible for an old, narrow range.
Once you can state the conflict plainly, such as 'package A needs the shared library below version three, but package B needs three or above,' the correct fix usually becomes obvious.
The most common and cleanest fix is to update one or more dependencies. Newer releases often relax or modernize their own version requirements.
Check whether the dependency imposing the older constraint has a newer version that widens its accepted range for the shared package.
In Xcode, adjust that dependency's version rule to allow the newer release, or use File then Packages then Update to Latest Package Versions to pull compatible updates across the board.
Many conflicts disappear simply because both packages have, in their latest versions, converged on a compatible range of the shared dependency.
After updating, resolve packages and run your tests. Updating is preferable to hacks because it keeps you on maintained versions, but always review release notes before accepting a major-version bump that could introduce breaking changes of its own.
If you or a dependency pinned a version too tightly, loosening the rule can create the overlap SPM needs.
Inspect your own direct dependencies for exact-version pins. An exact pin gives SPM zero flexibility, and it is a frequent cause of avoidable conflicts.
Where appropriate, change an exact pin to a range such as 'up to next major version.' This lets SPM choose a version that also satisfies the other package.
Be deliberate about which constraints you relax. Loosening a rule you set for a good reason, such as pinning around a known bug, may reintroduce that problem.
After adjusting rules, resolve again. Giving the resolver room to maneuver often turns an impossible constraint set into a solvable one without changing which libraries you depend on.
When the conflict comes from deep in the tree, you need to see the whole graph, not just your direct dependencies.
From the command line in your package directory, you can inspect the resolved dependency graph to see who requires what. This reveals the transitive chain that introduces the conflicting range.
Once you find the transitive culprit, your options are to update the direct dependency that pulls it in, or to contact or fork that dependency if it is stuck on an outdated requirement.
Sometimes the cleanest path is to replace a poorly maintained dependency with an actively maintained alternative that keeps its constraints current.
Tracing transitive dependencies takes patience, but it turns a vague conflict into a specific, actionable target. You cannot fix a constraint you have not located, so this step is often decisive.
Package.resolved records the versions SPM settled on, and mishandling it can cause conflicts that look worse than they are.
If a conflict appeared right after a merge, open Package.resolved and check for merge conflict markers. Resolving that file incorrectly can leave inconsistent pins.
When in doubt, delete Package.resolved and let SPM regenerate it from your manifest with a fresh resolution. This ensures the pins reflect a genuinely valid solution.
After regenerating, run your test suite to confirm the newly chosen versions behave as expected, then commit the file.
Treat Package.resolved as a generated artifact you review rather than edit by hand. Keeping it clean and letting SPM own its contents prevents a whole category of confusing, self-inflicted version conflicts across your team.
Occasionally two dependencies are genuinely incompatible and no update reconciles them. It is important to recognize this honestly rather than fight it forever.
If one library requires an old major version of a shared package and refuses to move, while another requires the new major version, you may have to choose between them.
Evaluate whether one of the conflicting libraries has a maintained alternative that plays well with the rest of your graph. Swapping it out is often the pragmatic answer.
In rare cases you might fork and update an unmaintained dependency yourself, then point at your fork until upstream catches up.
Throughout all of this, remember what SPM is and is not. It resolves native Swift dependencies; it does not build or ship your app for you. A finished native app still requires Xcode and the Apple Developer Program, so resolving these conflicts simply keeps that native pipeline moving.
Two dependencies requiring incompatible version ranges of the same shared package. SPM must pick one version for the whole graph, and if no version fits both, resolution fails.
Identify the shared package everyone disagrees about and the version ranges each dependency requires. The named packages and ranges point directly at where the overlap is missing.
Often yes. Newer releases frequently relax their version requirements, creating an overlap. Update the involved packages, then resolve and run your tests.
No. Treat it as a generated artifact. If it is conflicted after a merge, delete it and let SPM regenerate a valid resolution, then review and commit it.
You may need to replace one with a maintained alternative, or fork and update an unmaintained dependency. Sometimes choosing between the two libraries is unavoidable.