🌟 [Major]: New PowerShell module v1.0.0 with complete YAML 1.2.2 command suite

[Marius Storhaug (MariusStorhaug)]

Yaml v1.0.0 is the first public release of a new PowerShell module for the PowerShell Gallery, delivering a complete YAML 1.2.2 command suite for parsing, validating, formatting, merging, reading, writing, and targeted entry removal with no third-party runtime dependencies. This is the module go-live, so there are no breaking changes for existing consumers; the module targets PowerShell 7.6/Core.

New: Complete YAML 1.2.2 command suite

The module provides end-to-end YAML handling with ConvertFrom-Yaml, ConvertTo-Yaml, Test-Yaml, Import-Yaml, Export-Yaml, Format-Yaml, Merge-Yaml, and Remove-YamlEntry.

Command	User outcome
ConvertFrom-Yaml	Parse YAML text into PowerShell objects
ConvertTo-Yaml	Serialize PowerShell objects into YAML text
Test-Yaml	Validate YAML syntax and structure without object construction
Import-Yaml	Read YAML files directly into PowerShell objects
Export-Yaml	Write PowerShell objects directly to YAML files
Format-Yaml	Normalize YAML text with representation-preserving, idempotent output
Merge-Yaml	Deep-merge two or more YAML streams with configurable policy
Remove-YamlEntry	Remove entries by RFC 6901 JSON Pointer path

New: Native YAML 1.2.2 engine with no third-party dependencies

Parsing and serialization are implemented entirely in PowerShell — no YamlDotNet or other runtime dependency. The engine enforces bounded parse, clone, merge, removal, and emit work budgets, avoids arbitrary .NET type activation, and uses iterative graph traversal to stay stable on large or adversarial inputs. Duplicate YAML mapping keys are rejected by design to prevent ambiguous data projection.

New: YAML 1.2.2 conformance across the pipeline

The scanner, parser, constructor, serializer, and emitter are validated against the YAML 1.2.2 specification, including edge cases around BOM handling, NBSP behavior, flow scalars, and tag decoding.

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Technical details

• Consolidates the full YAML draft-stack delivery into release/v1.0.0, including prior preparatory PR slices (Draft: repository-owned YAML processor (Core 7.6+ conformance zero-fail) #37, 🪲 [Fix]: Escaped YAML tags preserve their exact identity #39, Harden YAML engine and conformance accounting #40, 🚀 [Feature]: YAML files can be imported and exported directly #41, 🚀 [Feature]: YAML streams can now be normalized safely #42, 🚀 [Feature]: YAML streams can now be merged without representation loss #45, 🚀 [Feature]: YAML entries can now be removed without representation loss #46).
• Implements a fully owned PowerShell YAML 1.2.2 pipeline (scanner -> parser/composer -> constructor -> projector -> serializer -> emitter) with no YamlDotNet dependency.
• Conformance baseline uses the 402-input yaml-test-suite corpus plus chapter 2 fixtures under tests/fixtures/yaml-spec-1.2.2/chapter-02/.
• This PR uses Major as the explicit release framing for the bootstrap integration merge to main that cuts v1.0.0; it is the module go-live, not a compatibility break against a prior release.

Standards and framework alignment pass (Pass A)

Changed surface	Standards checked	Framework docs checked	Result
src/functions/public/**, src/functions/private/**	MSX Coding Standards: PowerShell/Functions, Naming	PSModule Standards, Process-PSModule repository structure, module bootstrap	Aligned
tests/**	MSX Coding Standards: PowerShell/Testing	PSModule Standards, Process-PSModule build-test-pack-publish	Fixed in this PR
.github/workflows/**, .github/PSModule.yml, .github/linters/**	MSX Coding Standards: GitHub Actions	Process-PSModule repository structure and build-test-pack-publish	Aligned
README.md, examples/**	MSX Coding Standards: Documentation	PSModule Repository-Defaults, PSModule Standards	Aligned
Repository baseline files (CONTRIBUTING.md, SECURITY.md, SUPPORT.md, CODE_OF_CONDUCT.md, AGENTS.md, CLAUDE.md, .github/copilot-instructions.md, .github/pull_request_template.md)	MSX Ways of Working: Repository Standard	PSModule Repository-Defaults (required common files, managed distribution guidance)	Fixed in this PR

Issue convergence sweep (Pass B)

• Sweep scope: existing PR-linked candidates (#2, #4, #5, #7, #8, #20, #21, #22, #24, #25, #26, #27, #29, #43, #44) plus targeted open-issue searches by command names, YAML chapter-2/conformance terms, and representation-preserving file/merge/removal terms.
• Dedupe note: PSModule/Yaml#1 is a pull request, not an issue leaf, and PSModule/Yaml#3 is already closed historical work.

Convergence evidence by closed issue

• PSModule/Yaml#2 — core conversion surface delivered via ConvertFrom-Yaml and ConvertTo-Yaml, with coverage in tests/ConvertFrom-Yaml.Tests.ps1 and tests/ConvertTo-Yaml.Tests.ps1.
• PSModule/Yaml#4 — Test-Yaml delivered and covered in tests/Test-Yaml.Tests.ps1.
• PSModule/Yaml#5 — deterministic stream formatting delivered via Format-Yaml, covered in tests/Format-Yaml.Tests.ps1.
• PSModule/Yaml#7 and PSModule/Yaml#27 — flow sequence/mapping parsing delivered and covered in parser behavior tests and tests/Specification.Tests.ps1 chapter-2 examples.
• PSModule/Yaml#8 — multiline literal/folded scalar support delivered and covered in tests/ConvertFrom-Yaml.Tests.ps1 and chapter-2 examples.
• PSModule/Yaml#20 — chapter-2 compliance harness delivered in tests/Specification.Tests.ps1 (examples 2.01 through 2.28).
• PSModule/Yaml#21 — multi-document stream support delivered and validated in chapter-2 stream examples and command tests.
• PSModule/Yaml#22 — anchors/aliases support delivered and verified in tests/ConvertFrom-Yaml.Tests.ps1 and merge/removal behavior suites.
• PSModule/Yaml#24 — explicit tag and !! handling delivered and covered across conversion/specification tests.
• PSModule/Yaml#25 — complex mapping key handling delivered (including hashtable-safe paths) and covered in conversion/specification tests.
• PSModule/Yaml#26 — core-schema numeric forms and special floats delivered and covered in tests/ConvertFrom-Yaml.Tests.ps1, tests/ConvertTo-Yaml.Tests.ps1, and tests/Specification.Tests.ps1.
• PSModule/Yaml#29 — file I/O commands delivered via Import-Yaml and Export-Yaml, covered in tests/Import-Yaml.Tests.ps1 and tests/Export-Yaml.Tests.ps1.
• PSModule/Yaml#43 — representation-preserving merge delivered via Merge-Yaml, covered in tests/Merge-Yaml.Tests.ps1.
• PSModule/Yaml#44 — representation-preserving entry removal delivered via Remove-YamlEntry, covered in tests/Remove-YamlEntry.Tests.ps1.

Relevant issues (or links)

• Fixes Add ConvertFrom-Yaml and ConvertTo-Yaml functions #2
• Closes Add Test-Yaml function to validate YAML content #4
• Closes Add deterministic YAML stream formatting #5
• Closes Support inline (flow-sequence) arrays #7
• Closes Support multiline block scalar strings #8
• Closes Add YAML 1.2.2 Chapter 2 spec-compliance test harness #20
• Closes Support multi-document YAML streams #21
• Closes Support anchors and aliases #22
• Closes Support tags and !! shorthand #24
• Closes Support complex mapping keys #25
• Closes Support core-schema integer and float forms #26
• Closes Support flow mappings #27
• Closes Add Import-Yaml and Export-Yaml file I/O functions #29
• Closes Add representation-preserving YAML stream merging #43
• Closes Add representation-preserving YAML entry removal #44
• Support timestamp parsing #23 (partially convergent: explicit !!timestamp handling is delivered; implicit core-schema timestamp resolution remains open by design)
• Preserve comments through ConvertFrom-Yaml/ConvertTo-Yaml round-trip #28 (not convergent: comment-preserving ConvertFrom-Yaml | ConvertTo-Yaml round-trip is not delivered in this diff)
• Replace PowerShell operators with .NET methods for parsing and serialization performance #30 (partially convergent: parser/emitter hardening and budget controls shipped, but full operator-to-.NET substitution scope remains open)

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