Run CI on branch pushes again

.github/workflows/ci.yml

@@ -1,18 +1,26 @@
 name: CI
 
-# Unfiltered `push` as well as `pull_request` on purpose. The artifacts the build produces exist
-# so a change can be tried on a Pi or a Mac without building it there, and that only works if
-# every branch push produces them -- not just the ones that have a pull request open. The cost
-# is that a PR raised from a branch in this repo builds twice.
+# Every branch `push` as well as `pull_request` on purpose. The artifacts the build produces
+# exist so a change can be tried on a Pi or a Mac without building it there, and that only works
+# if every branch push produces them -- not just the ones that have a pull request open. The
+# cost is that a PR raised from a branch in this repo builds twice.
 #
 # Except tags, which belong to release.yml. Both workflows call the same build, and the
 # `concurrency` group below is keyed by workflow name, so nothing would collapse the pair: a
 # `v*` push would otherwise run the matrix twice over and report two statuses for one tag.
-# `tags-ignore` rather than a positive `branches` filter, so the sentence above stays "every
-# branch push, except --" instead of a list a reader has to check is exhaustive.
+#
+# The `branches` filter is what excludes them, and the rule behind it cuts both ways. A `push`
+# naming only branch filters does not fire for tags at all -- that is the whole of how a tag is
+# left to release.yml -- and the mirror of that rule is a trap worth naming: a `push` naming only
+# `tags` or `tags-ignore` does not fire for *branches*, so `tags-ignore: '**'` reads like
+# "everything except tags" and means "nothing at all".
+#
+# `'**'` and not `'*'`, because only the doubled form matches a `/`, and the branches here carry
+# two apiece. `'*'` would be this same bug wearing a better disguise: main would build and no
+# task branch would.
 on:
   push:
-    tags-ignore:
+    branches:
       - '**'
   pull_request:
 

.github/workflows/release.yml

@@ -2,8 +2,8 @@ name: Release
 
 # A human tags; this publishes what that tag builds. Nothing here creates a tag, and there is
 # no second trigger -- no branch push, no pull request, no schedule, no `workflow_dispatch` --
-# so the only way to reach `gh release create` is to have pushed a `v*` tag. `ci.yml` ignores
-# tags for the same reason, leaving one workflow to answer for one tag.
+# so the only way to reach `gh release create` is to have pushed a `v*` tag. `ci.yml` filters on
+# branches and so never fires for a tag, leaving one workflow to answer for one tag.
 on:
   push:
     tags:

docs/ROADMAP.md

@@ -1046,13 +1046,14 @@ operator to choose between `Type=simple` and `Type=forking` and write the unit t
   tee` returns 0 on a failed configure, and the assertion after it greps a truncated log —
   both callers green on a build that never configured. A fail-open gate is worse than no gate,
   which is the argument the shellcheck job at the top of `ci.yml` already makes.
-- **`ci.yml` gained a `tags-ignore`, and that is the whole of its *behavioural* change** —
-  the rest of its diff is the matrix moving out to `build.yml`. Its `push` was
+- **`ci.yml` gained a ref filter on its `push`, and that is the whole of its *behavioural*
+  change** — the rest of its diff is the matrix moving out to `build.yml`. Its `push` was
   unfiltered on purpose, and a `v*` push would otherwise have run the matrix twice over and
   reported two statuses for one tag — the `concurrency` group is keyed by workflow name, so
-  nothing collapses the pair. `tags-ignore` rather than a positive `branches: ['**']` filter,
-  so the existing "every branch push, on purpose" comment stays true with an exception named
-  rather than being rewritten as a list a reader has to check is exhaustive.
+  nothing collapses the pair. The filter is `branches: ['**']`, which is what excludes tags: a
+  `push` filtered on one kind of ref does not fire for the other kind at all. The inverse
+  spelling, `tags-ignore: ['**']`, reads like the same sentence but is that rule the other way
+  around, and stops branch pushes firing at all.
 - **Fail closed, in two places, because `needs:` only covers one of them.** `needs: build`
   catches a leg that went red. What it does not catch is a leg that went green *while
   publishing nothing* — `Upload` is `if: matrix.publish`, and `if-no-files-found: error`
@@ -1374,9 +1375,9 @@ on a null-sink-only, mDNS-less binary. The three platform legs additionally run
 test and upload the binary they built, kept 14 days.
 
 The matrix itself lives in `.github/workflows/build.yml`, called by `ci.yml` and by item 10's
-`release.yml` alike, so one definition answers for both paths; `ci.yml` carries a
-`tags-ignore` so a tag push builds once rather than twice. See item 10 for why that split is
-a reusable workflow rather than a composite action.
+`release.yml` alike, so one definition answers for both paths; `ci.yml` filters its `push` to
+`branches: ['**']`, which excludes tags, so a tag push builds once rather than twice. See item
+10 for why that split is a reusable workflow rather than a composite action.
 
 The unit harness is item 1's and unchanged: GoogleTest via `FetchContent` pinned to a tag,
 wired to CTest with `gtest_discover_tests()`, defaulting ON only when this is the top-level