feat(boot): build 4.0.0-4.0.7 from a third layout era

[amondnet]

Closes #137

What

Spring Boot 4.0.0–4.0.7 were refused by eraFor. They sit between the two Boot eras: 4.0.0 moved the Antora component to documentation/, but the root-aggregate-content archive is not published until 4.0.8. The component path and the assembly moved apart, so neither existing era covered the eight releases between them.

This adds a third era for 4.0.0–<4.0.8: the 4.x component path with ADR-0004's synthesized assembly, against the inputs 4.x moved. Declared oldest first, the table is now 3.3.0-<4.0.0 synthesized, 4.0.0-<4.0.8 synthesized (4.x paths), >=4.0.8 archive.

Widening a neighbour cannot express this — the 3.x era's paths do not exist at these tags, and the archive era's assembly would merge a zip that 404s. Reasoning and measurements are recorded in ADR-0005; ADR-0004 is untouched and still governs 3.3–3.x.

Measured, not assumed (2026-09-17)

Question the issue asked first	Answer
Which 4.0.x jars ship META-INF/spring-configuration-metadata.json	103, measured two independent ways that agree exactly: the partials the 4.0.8 archive ships, and the artifacts publishing a 4.0.0 and 4.0.7 jar with the file. Of the 34 other v4.0.0 modules, 4 publish no jar and 30 publish one with no metadata — spring-boot-test among them, as in 3.x
Does the attributes properties file keep its shape	Yes — same key=value shape, and 4.0.0's file is byte-identical to 4.0.8's (123 entries against 3.5.16's 111)
Is the BOM script readable at platform/	Yes — same library(...)/links DSL

The regression risk the issue flagged

AntoraAsciidocAttributes.java changed with the restructure: 4.x reads Jackson 3 from the tools.jackson coordinates, keeps the 2.x line as a second Jackson 2 Bom behind a new version-jackson2-databind, and drops pulsar-client-reactive-api. Running the port's 3.x table against a 4.x BOM silently withholds four attributes the corpus links through.

So the addDependencyVersion table is split into era-scoped BOOT_3_MANAGED_VERSIONS / BOOT_4_MANAGED_VERSIONS, threaded through SynthesisSources into both synthesizeAttributes and versionSourceBoms so the BOM fetch and the synthesis cannot disagree about which coordinates exist.

It is era-scoped rather than a union because both lines manage com.fasterxml.jackson.core:jackson-databind — a union would emit version-jackson2-databind for 3.x, where upstream names no such attribute. (Gating each row on its library being declared in the BOM was tried first and dropped: right answer, wrong reason, since upstream resolves the coordinate without consulting the library.)

Verification

Ground truth. 4.0.8 is one patch above the range and shares the module split, the moved paths and the Jackson coordinates. Reconstructing it from its tag and diffing against the descriptor its own content archive ships:

• 876 of 876 attributes identical, 0 differing, 0 missing
• 24 extra, all the version-<spring-data-module>-docs/-javadoc pairs fix(boot): emit the two attribute sets the 3.x corpus still links through #199 added deliberately

End to end under --strict, with the 4.0.8 archive build as the control:

Counter	4.0.0	4.0.7	4.0.8 (archive)
exit code	0	0	0
pages	147	147	239
synthesized attributes	899	900	n/a
unresolved attribute references	2	2	2
unresolved configprop:	0	0	0
empty include-code:: groups	1	1	1

The two residues are the same two files in all three builds — tutorial/first-application and how-to/native-image/developing-your-first-application, whose [source,shell] blocks omit subs="attributes" upstream. The 92-page gap is the generated appendix, the same Gradle-output gap ADR-0004 accepted for 3.x.

3.x non-regression checked at 3.3.0 and 3.5.16: no version-jackson2-databind, Jackson values unchanged on the 2.x coordinates.

Done when

$ bun run scripts/detect-upstream-versions.ts --project boot
boot: skipping 1 version(s) with unpublished upstream artifacts: 4.1.0
boot: 8 missing GA version(s): 4.0.0, 4.0.1, 4.0.2, 4.0.3, 4.0.4, 4.0.5, 4.0.6, 4.0.7

Tests

421 pass, 0 fail (was 382). No test was weakened or deleted. Six tests encoded the old "4.0 gap" behaviour and were retargeted at boundaries that still exist — for example "an era ceiling is exclusive" now asserts that 4.0.0 selects the 4.x era and 4.0.8 the archive era, instead of asserting 4.0.0 is refused. New coverage: era selection at 4.0.0/4.0.7/4.0.8, the 103-artifact metadata set, and versionSourceBoms resolving a different BOM set per era table.

bun test, bunx tsc --noEmit -p . and bun run lint are clean.

Out of scope

Releasing the eight versions and recording them in catalog.json is a separate step, to be done after merge. Tag pushes must go three at a time — GitHub creates no push event for the fourth and later tags in one push (#61).

---

Summary by cubic

Adds a third layout era so Spring Boot 4.0.0–4.0.7 become buildable; previously they were refused because 4.0.0 moved the Antora component to documentation/ while the content archive stayed unpublished until 4.0.8. The new era reconstructs the generated half from the tag's 4.x paths, and the managed-version attribute port is split era-scoped so 4.x's renamed Jackson coordinates register without leaking a version-jackson2-databind attribute into 3.x output.

New Features

• The synthesized era reads the moved inputs (documentation/…, platform/spring-boot-dependencies/build.gradle) plus 103 spring-boot-* metadata jars; reconstructing 4.0.8 from them reproduces all 876 attributes of its shipped descriptor, 0 differing.
• These releases omit the generated appendix (147 pages against 4.0.8's 239), the same gap ADR-0004 accepted for 3.x.
• 3.3.0 and 3.5.16 are regression-checked clean: no version-jackson2-databind, Jackson values unchanged on the 2.x coordinates.
• detect-upstream-versions.ts now lists 4.0.0–4.0.7; 4.1.0 stays blocked by the availability gate because its zip is unpublished.
• Reasoning and measurements are recorded in ADR-0006.

Migration

• Releasing the eight versions and recording them in catalog.json is a separate step after merge.
• Push release tags three at a time — GitHub creates no push event for the fourth and later tags in one push (ci(release): add a workflow_dispatch recovery path for an existing tag #61).

^{Written for commit 12258e0. Summary will update on new commits.}

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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🟢 Metrics 11 complexity · 0 duplication

Metric	Results
Complexity	11
Duplication	0

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[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge, with the previous synthesis-testing gap addressed and no new actionable issues identified.

Summary

Adds a third Spring Boot layout era, enabling 4.0.0–4.0.7 through synthesis from the relocated documentation inputs and 103 metadata jars.

• Uses era-specific managed-version tables for both BOM selection and attribute synthesis.
• Preserves the 3.x synthesis path and the archive-based assembly from 4.0.8 onward.
• The latest change addresses the previous testing finding: synthesis assertions distinguish Jackson 2 and Jackson 3 coordinates and ensure 3.x does not emit version-jackson2-databind.
• No new actionable issues were identified.

_{Reviews (3) · Last reviewed commit: "chore(tests): apply review suggestions o..."}

[codecov]

Codecov Report

❌ Patch coverage is 94.90446% with 8 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
scripts/fetch-upstream.ts	0.00%	8 Missing ⚠️

📢 Thoughts on this report? Let us know!

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud