Describe the split Gradle legs in comments and docs

The PR-tier comment and docs/testing/README.md still described an
agent + hosted leg per line. Say which job the old leg outlasted, and
rename the tier test's tuple to match its rows.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01L25ziyhTM91GYbb3nbj1XY

Author: claude

.github/workflows/ci.yml

@@ -1336,9 +1336,9 @@ jobs:
           # Lines that run both capstones run them in one leg (one Maven
           # install; the run step loops over `suite`).
           - {os: ubuntu-latest, suite: e2e_redirect_maven_build e2e_vendor_maven_build, jvm_tool: maven, maven: '3.9.16'}
-          # Real-Gradle capstones, PR tier: one leg per Gradle line x {agent +
-          # hosted, vendor + multi-project} on ubuntu, each on its line's LTS
-          # JDK. Every other OS x line x mode cell (and the JDK-ceiling,
+          # Real-Gradle capstones, PR tier: legs per Gradle line x {agent,
+          # hosted (three shards), vendor + multi-project} on ubuntu, each on
+          # its line's LTS JDK. Every other OS x line x mode cell (and the JDK-ceiling,
           # configuration-cache, Isolated Projects and real-Central rows) runs
           # in gradle-compatibility.yml. `suite` lists every binary the leg
           # runs (space-separated); the libtest filters select by the prefix
@@ -1353,8 +1353,8 @@ jobs:
           # names, and a catch-all that `--skip`s exactly those words, so a
           # new test always lands in some leg (test_ci_gradle_prefixes.py
           # keeps the skip list in sync). The agent suites get a leg of their
-          # own: run before `gradle_hosted_[345]` in one leg they took 4.3-6.2
-          # min, past coverage on slow hosts.
+          # own: sharing one with `gradle_hosted_[345]`, that leg took 4.3-6.2
+          # min and often outlasted the `coverage` job, setting `ci-ok`.
           - {os: ubuntu-latest, suite: 'e2e_gradle_discovery_build e2e_gradle_agent_build', jvm_tool: gradle, gradle: '9.8.0', java: '21', test_filter: '--ignored gradle_agent_'}
           - {os: ubuntu-latest, suite: e2e_redirect_gradle_build, jvm_tool: gradle, gradle: '9.8.0', java: '21', test_filter: '--ignored gradle_hosted_3 gradle_hosted_4 gradle_hosted_5'}
           # Real-sbt hosted (socket-patch.sbt) + vendored

docs/testing/README.md

@@ -55,7 +55,7 @@ reach Maven Central.
 
 | Tier | Where | Cells |
 | --- | --- | --- |
-| PR | `ci.yml` `e2e` job | ubuntu × {6.9.4 / JDK 11, 7.6.6 / JDK 17, 8.14.3 / JDK 21, 9.8.0 / JDK 21} × {agent + hosted, vendored + multi-project}, plus Windows 8.14.3 multi-project |
+| PR | `ci.yml` `e2e` job | ubuntu × {6.9.4 / JDK 11, 7.6.6 / JDK 17, 8.14.3 / JDK 21, 9.8.0 / JDK 21} × {agent, hosted (three shards), vendored + multi-project}, plus Windows 8.14.3 multi-project |
 | Full | [`gradle-compatibility.yml`](../../.github/workflows/gradle-compatibility.yml) (path-filtered PRs, nightly, manual) | {ubuntu, macOS arm64, Windows} × the four lines × {agent, hosted, vendored} = 36 cells; JDK ceilings (6.9 on 15, 7.6 on 19, 8.14 on 24); `--configuration-cache` (9.8.0 hosted and vendored); Isolated Projects (9.8.0 hosted, recording only); real Maven Central (8.14.3, #511 and #487) |
 
 Every full-tier cell uploads JSON probe reports (Gradle and JDK version, resolved jar

scripts/tests/test_ci_e2e_tiers.py

@@ -128,7 +128,7 @@ def test_bundle_reads_cargo_json(self):
 # HostedShards checks every hosted test runs in exactly one of them).
 HOSTED_SHARD_1 = ["gradle_hosted_3", "gradle_hosted_4", "gradle_hosted_5"]
 HOSTED_SHARD_2 = ["gradle_hosted_" + c for c in "bcdeflmnop"]
-AGENT_HOSTED = (
+AGENT_AND_HOSTED_SHARDS = (
     ("e2e_gradle_discovery_build e2e_gradle_agent_build", "--ignored gradle_agent_"),
     ("e2e_redirect_gradle_build", " ".join(["--ignored", *HOSTED_SHARD_1])),
     ("e2e_redirect_gradle_build", " ".join(["--ignored", *HOSTED_SHARD_2])),
@@ -171,7 +171,7 @@ def test_pr_rows_are_the_lean_table(self):
         gradle = [r for r in rows("e2e") if r.get("jvm_tool") == "gradle"]
         want = []
         for line, java in GRADLE_LINES.items():
-            for suite, test_filter in (*AGENT_HOSTED, VENDOR):
+            for suite, test_filter in (*AGENT_AND_HOSTED_SHARDS, VENDOR):
                 row = {"os": "ubuntu-latest", "suite": suite, "jvm_tool": "gradle", "gradle": line,
                        "java": java, "test_filter": test_filter}
                 # The allowance lasts only while a suite of the row is unlanded.