ci: validate every member with mcpp 2026.9.28.2; latest_mcpp -> 2026.9.28.2

2026.9.28.2 (mcpp-community/mcpp#730) changes what a member's build can see
on Windows (the runtime placement resolver, the action PATH, the depfile) and
the order of matching conditional tables; the one descriptor with two
target_cfg predicates, compat.libarchive, names two that never match one
target. No descriptor grammar changed, so min_mcpp does not move.

Author: Sunrisepeak

.github/workflows/validate.yml

@@ -357,7 +357,21 @@ env:
   # every member and platform.
   #
   # `index.toml` min_mcpp does not move: no descriptor grammar changed.
-  MCPP_VERSION: "2026.9.28.1"
+  # ── 2026-09-28: raised 2026.9.28.1 -> 2026.9.28.2 ─────────────────────────
+  #
+  # 2026.9.28.2 (mcpp-community/mcpp#730) changes four things a member's build
+  # can see: on Windows the files beside a program are decided by one runtime
+  # placement resolver, which places the toolset's C++ runtime over an older
+  # copy a dependency ships and states that copy once as a packaging fault; on
+  # Windows every action runs with the toolset's runtime directory first on
+  # PATH, so each action re-runs once after the raise; a GNU-dialect compile
+  # on Windows writes a depfile, so those members rebuild once; and matching
+  # conditional tables apply in order of selector specificity. The one
+  # descriptor with two `target_cfg` predicates, compat.libarchive, names two
+  # that never match one target (linux, macos), so no descriptor's flags move.
+  #
+  # `index.toml` min_mcpp does not move: no descriptor grammar changed.
+  MCPP_VERSION: "2026.9.28.2"
 
 jobs:
   lint:

index.toml

@@ -115,7 +115,12 @@
 # descriptor grammar. An engine from this release on that a later floor
 # leaves below min_mcpp reports the floor as a closing tip of the command that
 # refreshed the index, not as an error at the start of every command.
+# ── 2026-09-28: latest_mcpp -> 2026.9.28.2, min_mcpp unchanged ─────────────
+#
+# Moved in the pull request that moves validate.yml's pin to 2026.9.28.2,
+# which runs every member on every platform with it. The release changes no
+# descriptor grammar.
 [index]
 spec        = "1"
 min_mcpp    = "2026.9.18.3"
-latest_mcpp = "2026.9.28.1"
+latest_mcpp = "2026.9.28.2"