Refuse a 0.x minor mismatch, and republish the overview from the named release's tree

.gitea/workflows/release.yml

@@ -5,7 +5,7 @@ on:
   workflow_dispatch:
     inputs:
       overview_version:
-        description: 'Version the overview should tell adopters to pull (e.g. 0.1.0)'
+        description: 'Released version to republish the overview for, without the leading v (e.g. 0.1.0)'
         required: true
 
 jobs:
@@ -72,7 +72,11 @@ jobs:
     needs: [retag-image]
     runs-on: docker-host
     steps:
+      # Publish the named release's own tree, so the page never pairs one Plainpages tag with another
+      # release's sidecar pins. A version that was never released fails here.
       - uses: actions/checkout@v7.0.1
+        with:
+          ref: ${{ inputs.overview_version && format('refs/tags/v{0}', inputs.overview_version) || github.ref }}
       - name: Publish the Docker Hub overview
         env:
           DOCKERHUB_OVERVIEW_TOKEN: ${{ secrets.DOCKERHUB_OVERVIEW_TOKEN }}

README.md

@@ -607,17 +607,20 @@ provider/consumer semantics in `checkApiVersion`:
 | --- | --- | --- |
 | same major, same minor (patch ignored) | `ok` | load |
 | same major, plugin minor **<** host minor | `warn` | load, log — built against an older release; check that release's notes |
+| **major `0`**, any minor mismatch | `refuse` | **abort boot** — pre-1.0 the minor is the breaking slot |
 | same major, plugin minor **>** host minor | `refuse` | **abort boot** — plugin needs a newer host |
 | different major | `refuse` | **abort boot** — incompatible contract |
 | missing / not a valid semver | `refuse` | **abort boot** — must be declared |
 
 The plugin pins one exact version (no ranges, per the project's pinning rules); the *host* supplies
-the caret-style compatibility. One digit carries the whole release, so a **minor** means either the
-plugin contract changed or a dependency moved far enough to warrant one. A `warn` therefore says
-"built against an older release" rather than promising new plugin features; check that release's
-notes before assuming there is anything to adopt. While Plainpages is `0.x` every release shares major `0`, so a plugin
-built against `0.1.0` still loads on a `0.9.0` host with a `warn`; reaching `1.0.0` refuses everything
-built against `0.x`, which is the point of that milestone.
+the compatibility. One digit carries the whole release, so a **minor** means either the plugin
+contract changed or a dependency moved far enough to warrant one.
+
+While Plainpages is `0.x` the major stays `0`, which leaves the minor as the only slot a breaking
+change can use — so a minor mismatch is refused rather than warned: a plugin declaring `0.1.0` will
+not boot on a `0.2.0` host until it is rebuilt against it. Once `1.0.0` lands the minor becomes
+additive and the `warn` row applies, saying "built against an older release" rather than promising
+new features.
 
 ### Conflict rules
 

src/plugin-host/plugin.test.ts

@@ -86,6 +86,9 @@ test("checkApiVersion: semver compat — equal/patch ok, older minor warns, newe
   assert.equal(checkApiVersion("1.3.0", "1.2.0").level, "refuse"); // needs features a newer host has
   assert.equal(checkApiVersion("2.0.0", "1.5.0").level, "refuse"); // incompatible major (newer)
   assert.equal(checkApiVersion("1.0.0", "2.0.0").level, "refuse"); // incompatible major (older)
+  assert.equal(checkApiVersion("0.1.0", "0.1.9").level, "ok"); // pre-1.0 patch is still ignored
+  assert.equal(checkApiVersion("0.1.0", "0.2.0").level, "refuse"); // pre-1.0 the minor IS the breaking slot
+  assert.equal(checkApiVersion("0.2.0", "0.1.0").level, "refuse");
   for (const bad of ["1", "1.2", "v1.2.3", "01.2.3", "1.2.x", "", 1, undefined, null]) {
     assert.equal(checkApiVersion(bad).level, "refuse", `${String(bad)} must refuse`);
   }

src/plugin-host/plugin.ts

@@ -156,6 +156,12 @@ export function checkApiVersion(pluginVersion: unknown, hostVersion: string = HO
   if (plugin.major !== host.major) {
     return { level: "refuse", message: `plugin targets apiVersion ${pluginVersion}; host is ${hostVersion} — incompatible major` };
   }
+  // Pre-1.0 the major is pinned at 0 until the 1.0.0 milestone, so a breaking change can only land
+  // as a minor (release-tooling/next-version.ts shifts every level down). Treating that as additive
+  // would let a stale plugin boot and fail at runtime instead of at discovery.
+  if (host.major === 0 && plugin.minor !== host.minor) {
+    return { level: "refuse", message: `plugin targets apiVersion ${pluginVersion}; host is ${hostVersion} — pre-1.0 a minor is a contract break, rebuild against ${hostVersion}` };
+  }
   if (plugin.minor > host.minor) {
     return { level: "refuse", message: `plugin targets apiVersion ${pluginVersion} but host is ${hostVersion}; upgrade the host` };
   }