Why does a patch-version dependency bump still break my production app?

Semantic versioning is a convention, not a contract. Systematic analysis of software ecosystems confirms that patch and minor releases routinely introduce behavioral breaking changes that no static analysis tool detects, and 68 percent of observed npm breaks fall into this behavioral category that is hardest to catch automatically. The damage lands mostly through transitive dependencies, of which only 21 percent have any test coverage in the wild. Dependency scanners flag security CVEs but have no mechanism for detecting semantic incompatibilities two levels deep. A developer who updates one direct dependency today has no tool that tells them which production behavior will change.