Understanding Semantic Versioning: Principles, Pre‑release Identifiers, and Platform Syntax

Semantic versioning (semver) is a convention that encodes the nature of changes in a software version number, allowing developers to infer compatibility and the scope of updates simply by looking at the version string.

The article begins with a brief introduction that defines semantic versioning and states its purpose: to make version numbers informative and to help manage dependency complexity.

It then describes the common pre‑release identifiers— alpha , beta , rc (release candidate) and release —using a cake‑making analogy to illustrate how each stage represents increasing stability and completeness before the final product is shipped.

Next, the core semver format MAJOR.MINOR.PATCH is explained: increment the major version for incompatible API changes, the minor version for backward‑compatible feature additions, and the patch version for backward‑compatible bug fixes. The article also notes that pre‑release tags and build metadata can be appended to this base format.

A comprehensive table follows, showing how different package managers (Gradle, Maven, Pub, npm, CocoaPods, etc.) express version constraints such as exact versions, compatible ranges, wildcard versions, and exclusion rules. The table includes examples for each platform and brief descriptions of the semantics.

To validate version strings, the article recommends the npm node-semver library and provides two regular expressions (one for named groups and one for positional groups) that match the semver specification across languages like PCRE, Python, Go, and JavaScript.

The Q&A section answers common questions, such as whether a prefixed v1.2.3 is a valid semver, how to compare versions, and why published versions must never be altered after release.

Finally, the article concludes by summarizing the key points, encouraging readers to apply the rules in their projects, and inviting feedback in the comments.

Note: The original source also contains a brief recruitment notice for the "政采云技术" team, which is not part of the technical content.