Stable Releases: Definition and Process (#6394)

Closes: #1728
Related to #6522

CONTRIBUTING.md

@@ -254,21 +254,29 @@ all desired features and bug fixes are merged into as separate PRs.
 
 Example:
 
-Current release is `v0.38.4`. We then maintain a (living) branch `backport/release/v0.38.x`. As PRs
-are merged into master, if they wish to be backported into the next `v0.38.x` point release, the
-author must:
-
-1. Add `backport` label
-2. Pull latest changes on the desired `backport/release/v*.*.x` branch
-3. Create a 2nd PR merging the respective backport PR into `backport/release/v*.*.x`
-
-This means it is the authors responsibility to fix any merge conflicts, update changelog entries, and
-ensure CI passes. If a PR originates from an external contributor, it may be a team members responsibility
-to perform this process instead of the original author.
+Current release is `v0.38.4`. We then maintain a (living) branch `sru/release/v0.38.N`, given N as
+the next patch release number (currently `0.38.5`) for the `0.38` release series. As bugs are fixed
+and PRs are merged into `master`, if a contributor wishes the PR to be released as SRU into the
+`v0.38.N` point release, the contributor must:
+
+1. Add `0.38.N-backport` label
+2. Pull latest changes on the desired `sru/release/vX.X.N` branch
+3. Create a 2nd PR merging the respective SRU PR into `sru/release/v0.38.N`
+4. Update the PR's description and ensure it contains the following information:
+   - **[Impact]** Explanation of how the bug affects users or developers.
+   - **[Test Case]** section with detailed instructions on how to reproduce the bug.
+   - **[Regression Potential]** section with a discussion how regressions are most likely to manifest, or might
+   manifest even if it's unlikely, as a result of the change. **It is assumed that any SRU candidate PR is
+   well-tested before it is merged in and has an overall low risk of regression**.
+
+It is the PR's author's responsibility to fix merge conflicts, update changelog entries, and
+ensure CI passes. If a PR originates from an external contributor, it may be a core team member's
+responsibility to perform this process instead of the original author.
+Lastly, it is core team's responsibility to ensure that the PR meets all the SRU criteria.
 
 Finally, when a point release is ready to be made:
 
-1. Create `release/v*.*.x` branch
+1. Create `release/v0.38.N` branch
 2. Ensure changelog entries are verified
    2. Be sure changelog entries are added to `RELEASE_CHANGELOG.md`
 3. Add release version date to the changelog
@@ -286,8 +294,8 @@ alive, the core contributor team will strive to permit special repo privileges
 to developers who show an aptitude towards developing with this code base.
 
 Several different kinds of privileges may be granted however most common
-privileges to be granted are merge rights to either part of, or the entire the
-code base (though the github `CODEOWNERS` file). The on-boarding process for
+privileges to be granted are merge rights to either part of, or the entirety of the
+code base (through the github `CODEOWNERS` file). The on-boarding process for
 new code owners is as follows: On a bi-monthly basis (or more frequently if
 agreeable) all the existing code owners will privately convene to discuss
 potential new candidates as well as the potential for existing code-owners to
@@ -300,7 +308,7 @@ Only if unanimous consensus is reached among all the existing code-owners will
 an invitation be extended to a new potential-member. Likewise, when an existing
 member is suggested to be removed/or have their privileges reduced, the member
 in question must agree on the decision for their removal or else no action
-should be taken. If however, a code-owner is verifiably shown to intentionally
+should be taken. If however, a code-owner is demonstrably shown to intentionally
 have had acted maliciously or grossly negligent, code-owner privileges may be
 stripped with no prior warning or consent from the member in question.
 

STABLE_RELEASES.md

@@ -0,0 +1,131 @@
+# Stable Releases
+
+*Stable Release Series* continue to receive bug fixes until they reach **End Of Life**.
+
+Only the following release series are currently supported and receive bug fixes:
+
+The `0.37.x` release series will continue receiving bug fixes until the Cosmos Hub
+migrates to a newer release of the Cosmos-SDK.
+
+* **0.37** will continue receiving bug fixes until the Cosmos Hub migrates to a newer release series of the Cosmos-SDK.
+* **0.39 «Launchpad»** will be supported until 6 months after **0.40.0** is published. A fairly strict **bugfix-only** rule applies to pull requests that are requested to be included into a stable point-release.
+
+The **0.39 «Launchpad»** release series is maintained in compliance with the **Stable Release Policy** as described in this document.
+
+## Stable Release Policy
+
+This policy presently applies *only* to the following release series:
+
+* **0.39 «Launchpad»**
+
+### Point Releases
+
+Once a Cosmos-SDK release has been completed and published, updates for it are released under certain circumstances
+and must follow the [Point Release Procedure](CONTRIBUTING.md).
+
+### Rationale
+
+Unlike in-development `master` branch snapshots, **Cosmos-SDK** releases are subject to much wider adoption,
+and by a significantly different demographic of users. During development, changes in the `master` branch 
+affect SDK users, application developers, early adopters, and other advanced users that elect to use
+unstable experimental software at their own risk.
+
+Conversely, users of a stable release expect a high degree of stability. They build their applications on it, and the
+problems they experience with it could be potentially highly disruptive to their projects.
+
+Stable release updates are recommended to the vast majority of developers, and so it is crucial to treat them
+with great caution. Hence, when updates are proposed, they must be accompanied by a strong rationale and present
+a low risk of regressions, i.e. even one-line changes could cause unexpected regressions due to side effects or
+poorly tested code. We never assume that any change, no matter how little or non-intrusive, is completely exempt
+of regression risks.
+
+Therefore, the requirements for stable changes are different than those that are candidates to be merged in
+the `master` branch. When preparing future major releases, our aim is to design the most elegant, user-friendly and
+maintainable SDK possible which often entails fundamental changes to the SDK's architecture design, rearranging and/or
+renaming packages as well as reducing code duplication so that we maintain common functions and data structures in one
+place rather than leaving them scattered all over the code base. However, once a release is published, the
+priority is to minimise the risk caused by changes that are not strictly required to fix qualifying bugs; this tends to
+be correlated with minimising the size of such changes. As such, the same bug may need to be fixed in different
+ways in stable releases and `master` branch.
+
+### What qualifies as a Stable Release Update (SRU)
+
+* **High-impact bugs**
+  * Bugs that may directly cause a security vulnerability.
+  * *Severe regressions* from a Cosmos-SDK's previous release. This includes all sort of issues
+    that may cause the core packages or the `x/` modules unusable.
+  * Bugs that may cause **loss of user's data**.
+* Other safe cases:
+  * Bugs which don't fit in the aforementioned categories for which an obvious safe patch is known.
+  * Relatively small yet strictly non-breaking changes that introduce forward-compatible client
+    features to smoothen the migration to successive releases.
+
+### What does not qualify as SRU
+
+* State machine changes.
+* New features that introduces API breakages (e.g. public functions removal/renaming).
+* Cosmetic fixes, such as formatting or linter warning fixes.
+
+## What pull requests will be included in stable point-releases
+
+Pull requests that fix bugs that fall in the following categories do not require a **Stable Release Exception** to be granted to be included in a stable point-release:
+
+ * **Severe regressions**.
+ * Bugs that may cause **client applications** to be **largely unusable**.
+ * Bugs that may cause **state corruption or data loss**.
+ * Bugs that may directly or indirectly cause a **security vulnerability**.
+
+## What pull requests will NOT be automatically included in stable point-releases
+
+As rule of thumb, the following changes will **NOT** be automatically accepted into stable point-releases:
+
+ * **State machine changes**.
+ * **Client application's code-breaking changes**, i.e. changes that prevent client applications to *build without modifications* to the client application's source code.
+
+ In some circumstances, PRs that don't meet the aforementioned criteria might be raised and asked to be granted a *Stable Release Exception*.
+
+## Stable Release Exception - Procedure
+
+1. Check that the bug is either fixed or not reproducible in `master`. It is, in general, not appropriate to release bug fixes for stable releases without first testing them in `master`. Please apply the label [0.39 «Launchpad»](https://github.com/cosmos/cosmos-sdk/labels/0.39%20LTS%20%28Launchpad%29) to the issue.
+2. Add a comment to the issue and ensure it contains the following information (see the bug template below):
+ * **[Impact]** An explanation of the bug on users and justification for backporting the fix to the stable release.
+ * A **[Test Case]** section containing detailed instructions on how to reproduce the bug.
+ * A **[Regression Potential]** section with a clear assessment on how regressions are most likely to manifest as a result of the pull request that aims to fix the bug in the target stable release.
+3. **Stable Release Managers** will review and discuss the PR. Once *consensus* surrounding the rationale has been reached and the technical review has successfully concluded, the pull request will be merged in the respective point-release target branch (e.g. `release/launchpad/0.39.X` being `X` the Launchpad's upcoming point-release) and the PR included in the point-release's respective milestone (e.g. `0.39.5`).
+
+### Stable Release Exception - Bug template
+
+```
+#### Impact
+
+Brief xplanation of the effects of the bug on users and a justification for backporting the fix to the stable release.
+
+#### Test Case
+
+Detailed instructions on how to reproduce the bug on Launchpad's most recently published point-release.
+
+#### Regression Potential
+
+Explanation on how regressions might manifest - even if it's unlikely.
+It is assumed that stable release fixes are well-tested and they come with a low risk of regressions.
+It's crucial to make the effort of thinking about what could happen in case a regression emerges.
+```
+
+## Stable Release Managers
+
+The **Stable Release Managers** evaluate and approve or reject updates and backports to Cosmos-SDK Stable Release series,
+according to the [stable release policy](#stable-release-policy) and [release procedure](#stable-release-exception-procedure).
+Decisions are made by consensus.
+
+Their responsibilites include:
+ * Driving the Stable Release Exception process.
+ * Approving/rejecting proposed changes to a stable release series.
+ * Executing the release process of stable point-releases in compliance with the [Point Release Procedure](CONTRIBUTING.md).
+
+The Stable Release Managers are appointed by the Interchain Foundation.
+
+*Stable Release Managers* for the **0.39 «Launchpad»** release series follow:
+
+* @alessio - Alessio Treglia
+* @clevinson - Cory Levinson-
+* @ethanfrey - Ethan Frey