CI: cut the run from ~24 min to ~14 min

.github/scripts/shard-assign.sh

@@ -0,0 +1,165 @@
+#!/usr/bin/env bash
+#
+# Prints, one per line, the test .csproj paths assigned to shard $SHARD_INDEX of
+# $SHARD_TOTAL.
+#
+# 🚨 Used by BOTH jobs in dotnet-test.yml and they MUST agree:
+#   * `build` calls it once per shard to pack that shard's test bins into its OWN
+#     artifact (so a shard downloads ~1/6 of the output instead of all 3.3 GB);
+#   * `test` calls it to decide which projects to run.
+# If the two ever disagreed, a shard would run a project whose bin it never
+# downloaded. That is why the assignment lives in one file instead of being
+# duplicated in two `run:` blocks.
+#
+# Portable on purpose: no `declare -A`, so it runs on the runner's bash 5 AND on
+# a stock macOS bash 3.2 — you can verify a change locally before pushing.
+#   SHARD_INDEX=0 SHARD_TOTAL=6 .github/scripts/shard-assign.sh
+#
+# ── Balancing ────────────────────────────────────────────────────────────────
+# Greedy LPT: heaviest first onto the currently least-loaded shard, ties to the
+# lowest shard id. Explicit and ORDER-INDEPENDENT — the original
+# `counter % SHARD_TOTAL` over a sorted csproj list silently depended on locale
+# byte order (C-locale sorts MeshWeaver.AI.Test BEFORE MeshWeaver.Acme.Test,
+# 'I' 0x49 < 'c' 0x63), which stacked AI + Orleans — two of the three
+# ALC-heaviest projects — onto shard 0 and made it the ~19-minute long pole of
+# every run.
+#
+# Weights are wall-clock SECONDS, the MAX over two green runs (30903428924 and
+# 30903158378, both 2026-08-04) so a shard is sized for the bad case, not the
+# average. The per-project `[CI] <name> exit=` markers in the test job's log ARE
+# the measurement: take the delta between each `::group::<name>` and its marker.
+# Re-measure when a project's runtime changes materially — the previous table
+# (2026-07-13) had drifted far enough to cost ~100 s of long pole (Monolith
+# 200→345, Data 25→73, PluginTester 60→8, Persistence 165→97).
+#
+# The floor for ANY sharding is the heaviest single project: today
+# Hosting.Monolith.Test at 345 s. Adding shards below that buys nothing.
+#
+# Unlisted projects get DEFAULT_WEIGHT — a deliberate over-estimate, since an
+# unlisted project is a NEW one whose cost nobody has measured yet.
+#
+# ── Splitting a heavyweight across shards ────────────────────────────────────
+# An optional THIRD column splits one project into N parts, each weighted 1/N and
+# scheduled independently — so the halves land on DIFFERENT shards, i.e. different
+# runners. That matters twice over: it lowers the floor (no amount of sharding can
+# beat the heaviest single project), and it introduces no shared-resource contention,
+# because two runners share nothing. `maxParallelThreads: 1` is per-process and stays
+# intact.
+#
+# A split entry prints as `<csproj>#<part>/<parts>`; the test job turns that into an
+# `-class` filter list by enumerating the assembly's classes and taking every Nth.
+# The BUILD job strips the suffix, so a split project's bin is packed into every shard
+# that runs one of its parts.
+set -euo pipefail
+
+: "${SHARD_INDEX:?SHARD_INDEX must be set}"
+: "${SHARD_TOTAL:?SHARD_TOTAL must be set}"
+
+DEFAULT_WEIGHT=10
+
+# "<seconds> <project-name>", heaviest first.
+WEIGHTS=$(cat <<'EOF'
+345 MeshWeaver.Hosting.Monolith.Test 2
+263 MeshWeaver.AI.Test 2
+239 MeshWeaver.Hosting.Orleans.Test
+130 MeshWeaver.Hosting.PostgreSql.Test
+104 MeshWeaver.Threading.Test
+97 MeshWeaver.Persistence.Test
+91 MeshWeaver.Content.Test
+73 MeshWeaver.FutuRe.Test
+73 MeshWeaver.Data.Test
+62 MeshWeaver.Acme.Test
+53 MeshWeaver.Security.Test
+51 MeshWeaver.GitSync.Test
+49 MeshWeaver.Autocomplete.Test
+49 MeshWeaver.Query.Test
+33 MeshWeaver.Auth.Test
+31 MeshWeaver.Graph.Test
+30 MeshWeaver.PluginCatalog.Test
+27 MeshWeaver.NodeOperations.Test
+26 MeshWeaver.InstanceSync.Test
+22 MeshWeaver.Messaging.Hub.Test
+18 MeshWeaver.Layout.Test
+15 MeshWeaver.Markdown.Test
+15 MeshWeaver.Import.Test
+14 MeshWeaver.Courses.Test
+12 MeshWeaver.PathResolution.Test
+12 MeshWeaver.ContentCollections.Indexing.Graph.Test
+12 MeshWeaver.MemexTemplate.Test
+9 MeshWeaver.Northwind.Test
+8 MeshWeaver.PluginTester.Test
+8 MeshWeaver.PythonDemo.Test
+7 MeshWeaver.ContentCollections.Indexing.PostgreSql.Test
+6 MeshWeaver.AccessControl.Test
+5 MeshWeaver.Hosting.Grpc.Test
+5 MeshWeaver.Todo.Test
+4 MeshWeaver.MathDemo.Test
+4 MeshWeaver.Hosting.Test
+3 Memex.Portal.Shared.Test
+3 MeshWeaver.Social.Test
+3 MeshWeaver.Hosting.Sqlite.Test
+3 MeshWeaver.Hosting.Blazor.Test
+3 MeshWeaver.ContentCollections.Test
+3 MeshWeaver.Documentation.Test
+2 MeshWeaver.Serialization.Test
+2 MeshWeaver.Markdown.Export.Test
+1 MeshWeaver.TestDomain
+1 MeshWeaver.Data.TestDomain
+1 MeshWeaver.Hub.Fixture
+1 MeshWeaver.AI.Test.FakeCli
+1 MeshWeaver.Portal.E2E.Test
+1 MeshWeaver.Search.Test
+1 MeshWeaver.Reactive.Assertions.Test
+1 MeshWeaver.DataSetReader.Test
+1 MeshWeaver.Markdown.Collaboration.Test
+1 MeshWeaver.Maui.E2E.Test
+1 MeshWeaver.Maui.Abstractions.Test
+1 MeshWeaver.Maui.Integration.Test
+1 MeshWeaver.PluginImage.Test
+1 MeshWeaver.Hosting.Snowflake.Test
+1 MeshWeaver.Connection.SignalR.Test
+1 MeshWeaver.Speech.Test
+1 MeshWeaver.ContentCollections.Indexing.Test
+1 MeshWeaver.Kernel.Test
+EOF
+)
+
+weights_file=$(mktemp)
+trap 'rm -f "$weights_file"' EXIT
+printf '%s\n' "$WEIGHTS" > "$weights_file"
+
+# Only Cosmos is excluded — it needs the Cosmos emulator, which is heavy to set
+# up on a runner. Everything else runs (PostgreSql via Testcontainers on the
+# pre-installed Docker, Orleans via in-proc TestCluster, Acme/FutuRe via dynamic
+# Code-piece compilation).
+#
+# The weights arrive as a FILE, not `awk -v` — macOS's awk rejects a -v value
+# containing newlines ("newline in string"), so the -v form silently worked on
+# the runner while failing for anyone verifying a change locally.
+find test -name '*.csproj' ! -path '*Cosmos*' ! -path '*/bin/*' \
+  | awk -v dflt="$DEFAULT_WEIGHT" '
+      FNR == NR { if (NF >= 2) { weight[$2] = $1; if (NF >= 3) parts[$2] = $3 } next }
+      {
+        name = $0; sub(/.*\//, "", name); sub(/\.csproj$/, "", name)
+        w = (name in weight ? weight[name] : dflt)
+        n = (name in parts ? parts[name] : 1)
+        if (n <= 1) { printf "%06d %s %s\n", w, name, $0; next }
+        # Each part is its own schedulable unit at 1/N the weight.
+        for (i = 1; i <= n; i++)
+          printf "%06d %s#%d/%d %s#%d/%d\n", int(w / n), name, i, n, $0, i, n
+      }' "$weights_file" - \
+  | sort -k1,1nr -k2,2 \
+  | awk -v idx="$SHARD_INDEX" -v total="$SHARD_TOTAL" '
+      BEGIN { for (i = 0; i < total; i++) loads[i] = 0 }
+      {
+        best = 0
+        for (i = 1; i < total; i++) if (loads[i] < loads[best]) best = i
+        loads[best] += $1 + 0
+        if (best == idx) print $3
+      }
+      END {
+        # Diagnostics on stderr — stdout is the machine-readable csproj list.
+        s = ""
+        for (i = 0; i < total; i++) s = s " " loads[i]
+        printf "shard-assign: shard %s/%s, weighted loads:%s\n", idx, total, s > "/dev/stderr"
+      }'