[leehack]

Summary

Batch integration PR for 0.19.5 (plan #1899), per doc/high_risk_pre_merge_readiness.md "Batch integration PR". Seven constituents, one commit each, cut from main at 33e00f5a7. #1798 is not included and lands on its own later. Do not squash-merge: rebase merge only.

Closes #1905. The other constituents carry no closing keyword (#1901, #1902 and #1907/#1909 use Refs); they are tracker items under #1861, #1898 and #174, which are not closed by this PR.

Constituents (commit order)

All are high-risk per classify_high_risk_changes.dart; each head below is the head that was audited. Evidence: /opt/UnitySrc/personal/llama/llamadart-evidence/pr-N/.

#	PR	Risk	Pinned head	Own diff against	Audit	Evidence
1	#1901 LiteRT-LM Web getContextSize reports the enforced limit	high (backendRuntime)	d2f58aaa5d8602bedfe3f66156954853aaf1bd00	d739cfdb8	independent audit: PASS, 0 P1/P2 (evaluator exit 2)	pr-1901/
2	#1902 pub_content_limits comment-only	high (releaseAutomation, comment-only)	d4fa3267a3d13bafc42a3d18a22ac5889a30704e	d739cfdb8	independent audit: PASS, 0 P1/P2 (comment-only route, exit 2)	pr-1902/
3	#1906 Qwen3-Coder / StepFun / Nemotron parity	high (structuredOutput)	61a3140d0ee37846d0dd775a621a408c5f8b64ea	33e00f5a7	independent audit: PASS on re-audit, 0 P1/P2 (exit 2)	pr-1906/
4	#1908 Seed-OSS parity	high (structuredOutput)	6e241a3617521805d000b33859740da3cb94bf7d	61a3140d0 (#1906 head)	independent audit: PASS on re-audit, 0 P1/P2 (exit 2)	pr-1908/
5	#1910 MiniMax M3 forced-open thought	high (structuredOutput)	99b9c89605808400e955de3ef4113cf52fb0360f	33e00f5a7	independent audit: PASS on re-audit, 0 P1/P2 (exit 2)	pr-1910/
6	#1907 LiteRT-LM JSON Schema contract	high (backendRuntime, regressionPolicy, structuredOutput)	18e3993fc84fdbe7a99f9e7e8d0f66330428d3ff	33e00f5a7	ACCEPT at 18e3993f (0 P1/P2); waiver below	pr-1907/
7	#1909 LiteRT-LM JSON Schema platforms	high (backendRuntime, regressionPolicy, structuredOutput)	bc5d97267c628aa0832c40c3657d207d31f49da9	18e3993fc (#1907 head)	independent audit: ACCEPT on re-audit, 0 P1/P2 (exit 2, bound to base 18e3993)	pr-1909/

The constituent PR bodies still say "audit pending" for some rows; the integration audit and this table are the record for the batch.

Maintainer waiver (#1907)

One-time waiver (2026-11-10) of the compiled_grammar_acceptance and compiled_grammar_rejection axes, conditional on the audit confirming #1907 compiles no grammar; the re-audit at 18e3993f confirmed it. The evaluator has no waiver flag, so it exits 1 (missingStructuredOutputEvidence) on exactly those two axes; all other axes are met. Details in the #1907 PR body.

Conflict resolutions

None. Every constituent diff applied onto the integration tree with git apply --3way and no conflicts, including the shared docs (template-engine-internals.md, both changelogs, support matrix, README, skills).

Verification that the tree is the union of the audited diffs: for each commit, the added/removed lines of git diff -U0 <base> <pinned head> equal those of the commit, except one added blank line after ## Unreleased in each changelog (it is added once by the first constituent that fills the section, so later PRs' own blank line is not repeated). Changelogs: each of the 6 bullets (#1901, #1906, #1908, #1910, #1907, #1909; #1902 has none) is exactly once under ## Unreleased in CHANGELOG.md and website/docs/changelog/recent-releases.md; released sections untouched.

Commit subjects are the PR titles with (#N) appended where the title did not already end in it; the body is (#N, audited head <sha>).

Production-readiness scope

• User-facing scope: see the constituents.
• Supported platforms/paths: native LiteRT-LM strict responseFormat widened per Widen native LiteRT-LM JSON Schema to Gemma 4, macOS GPU and the shared schema contract #1907/Gate native LiteRT-LM JSON Schema per qualified host and accelerator #1909; Web LiteRT-LM context size; template parsers for Qwen3-Coder, Nemotron, StepFun, Seed-OSS and MiniMax M3.
• Unsupported or intentionally unavailable paths: unchanged from the constituents; unsupported schema/host/accelerator combinations throw LlamaUnsupportedException.
• Out of scope / follow-ups: #1798 lands separately; plan #1899.

Completeness checklist

• Declared scope is fully implemented (each constituent as audited).
• Unsupported platform/option combinations fail loudly (per constituents).
• Docs, support matrices, examples and changelog entries updated by the constituents.
• Regression coverage per constituents.
• Validation coverage registry: per Widen native LiteRT-LM JSON Schema to Gemma 4, macOS GPU and the shared schema contract #1907/Gate native LiteRT-LM JSON Schema per qualified host and accelerator #1909; validation_coverage_test.dart passes in the VM suite.
• No secrets or signed URLs added.
• Follow-ups tracked: None beyond the above.

PR type guidance

• Feature/Bugfix PR: see the constituent PRs; this PR adds no code beyond their diffs.

Test Plan

Local, on the combined tree at a9c777252, Flutter 3.47.1:

• dart run tool/prepare_workspace.dart (clean tree after)
• dart format --output=none --set-exit-if-changed .
• dart analyze: no issues
• dart run tool/testing/check_platform_boundaries.dart
• dart test -p vm -j 1 --exclude-tags local-only --coverage=coverage: 13511 passed, 129 skipped, 6 failed; all 6 are in test/unit/tooling/windows_registry_qualification_test.dart and fail with ProcessException: pwsh: No such file or directory (PowerShell is not installed on this host; CI has it). Same 6 in dart test -p vm test/unit/tooling/.
• dart test -p chrome --exclude-tags local-only: pass
• coverage-lib: lcov 93.73%, threshold 70 met
• tool/testing/run_template_parity_suites.sh: pass
• Other: real-model smokes on the combined tree (integration audit): litert-lm-json-schema with Gemma 4 E2B, CPU and GPU, PASS. gguf-chat-features-smoke with Qwen3.5-2B Q4_K_M: required tool calls pass; toolCallWithThinkingBudget fails byte-identically on main 33e00f5a, so it is pre-existing and filed separately.

Matrix Evidence

Matrix row	Scope covered	Platform / model / backend	Result	Evidence / notes
static-format-analyze	format, analyzer, import boundaries	macOS host	PASS
root-vm	VM suite	macOS arm64	PASS except 6 pwsh-missing tests	see Test Plan
root-chrome	browser suite	Chrome	PASS
coverage-lib	lib coverage	macOS arm64	PASS	93.73%
high-risk-exact-head-independent-qa	integration audit	a9c77725	PASS	Fresh auditor session, 0 P1/P2. The combined tree equals the union of the audited diffs. No cross-constituent parse or stream changes. 43 mutation controls re-run and killed. Evaluator exit 2. llamadart-evidence/pr-1912/
structured-output-adversarial	per constituent		per constituent; #1907 waiver above	llamadart-evidence/pr-N/

Review Notes

• Independent review status: constituent audits as listed; integration audit PASS at a9c77725 (0 P1/P2).
• CI status / head SHA: all 35 non-skipped checks green (9 skipped), a9c77725258e8d69d48231b11047bda1f91b1ce0; no reruns.
• Unresolved review threads: 0 on Batch integration for 0.19.5: #1901 #1902 #1906 #1908 #1910 #1907 #1909 #1912 and on each of the seven constituents (verified by the integration audit).

High-risk regression review

git diff --name-only --no-renames origin/main...HEAD | dart run tool/testing/classify_high_risk_changes.dart:

Classification: high-risk
Surfaces: backendRuntime, regressionPolicy, releaseAutomation, structuredOutput
Required matrix: dart run tool/testing/test_matrix.dart --tier high-risk

• Classification: high-risk
• Implementation task: the seven constituent PRs; integration by lane-0195-integration
• Independent blocking QA task: integration audit PASS at a9c77725, 0 P1/P2, evaluator exit 2 (unverifiedPrerequisites)
• Exact head / current base: a9c77725258e8d69d48231b11047bda1f91b1ce0 / 33e00f5a7a85083664843c3d5fdec2f1e6dcab53
• Production-branch deletion, bypass, or miswire proof: per constituent evidence; none added here
• Affected-family real-model/artifact evidence: per constituent (llamadart-evidence/pr-N/)
• Explicit unavailable-family or other N/A evidence: Widen native LiteRT-LM JSON Schema to Gemma 4, macOS GPU and the shared schema contract #1907 compiled_grammar_* waiver above
• Known PR-caused P1 regressions: 0
• Unresolved review threads: 0

[github-actions]

Chat app preview removed for leehack/llamadart-chat-pr-1912.