refactor(strcase,BREAKING!): adopt STYLE2024 case conversion rules

[Kybxd]

Motivation

The internal/strcase package was forked long ago from iancoleman/strcase and produced names that diverge from the Protobuf STYLE2024 and Edition 2024: features.enforce_naming_style guide:

• It inserted underscores at letter↔digit boundaries (Tier1 → tier_1), which STYLE2024 explicitly forbids.
• It treated all-caps acronyms as a single token (JSONData → various forms depending on the acronym table) instead of as ordinary words.
• It carried a long tail of unused helpers (ToLowerCamel, ToKebab, ToDelimited, …) inherited from upstream.

Meanwhile downstream code (protogen, confgen) kept patching around these rough edges with ad-hoc prefix logic and ToCamel/ToPascal swaps. This MR reworks the package to STYLE2024 in one place, removes the workarounds at call sites, and regenerates the affected test fixtures.

What changes

internal/strcase — core rewrite

• New chunk-based PascalCase / snake_case algorithm in camel.go / snake.go. STYLE2024 invariants:

  • Underscores only appear before a letter (Tier1 → tier1, never tier_1).
  • Acronyms are ordinary words (GetDnsRequest / dns_request, userID → user_id).

• Public API trimmed to the four conversions actually needed:

  Function	Result
  ToPascal(s)	AnyKindOfString
  ToCamel(s)	anyKindOfString
  ToSnake(s)	any_kind_of_string
  ToScreamingSnake(s)	ANY_KIND_OF_STRING

  ToCamel now produces anyKindOfString (i.e. previous ToLowerCamel semantics). ToLowerCamel, ToKebab, ToScreamingKebab, ToDelimited, ToScreamingDelimited, ToSnakeWithIgnore are removed.

• New helper EnumValue(enumName, value) (enum_value.go) producing STYLE2024-compliant enum value names: prefixes with UPPER_SNAKE_CASE(enumName), normalizes the value, and inserts a leading V when the value would otherwise start with a digit. Examples:

  EnumValue("DeviceTier", "Tier1")           -> "DEVICE_TIER_TIER1"
  EnumValue("DeviceTier", "1")               -> "DEVICE_TIER_V1"
  EnumValue("ItemType",   "EQUIP")           -> "ITEM_TYPE_EQUIP"
  EnumValue("ItemType",   "ITEM_TYPE_EQUIP") -> "ITEM_TYPE_EQUIP"
  

• doc.go / README.md rewritten to describe the STYLE2024 contract and the (now smaller) public surface.

• Tests rewritten against the new rules; new enum_value_test.go covers EnumValue plus an acronym-context regression case.

Call sites updated to use the new API

• internal/confgen (util.go, table_parser.go, document_parser.go): default field/column/node name derivation switches from ToCamel to ToPascal so the proto field hero_id continues to map to the sheet/document name HeroId under the new rules.
• internal/protogen/exporter.go: union enum value names go through EnumValue("Type", field.Name); when an explicit message type is not provided, the type name is derived via ToPascal(field.Name).
• internal/protogen/sheet_mode.go: enum value naming for sheet-mode enums goes through EnumValue(ws.Name, value.Name); the ad-hoc prefix-prepend logic is removed.
• internal/tools/cmd/ecode/main.go: directly uses ToCamel for the Go field name (replaces the previous PascalCase + manual lower-first hack).

Options — deprecation

options.ProtoOutputOption.EnumValueWithPrefix is deprecated and now a no-op. STYLE2024 mandates the enum-name prefix unconditionally, so the option no longer makes sense. The field is kept for config-schema backward compatibility; updated godoc reflects this. The functional test setup (test/functest/util.go) drops its usage.

Breaking changes

This MR will change generated .proto content for any sheet whose names contain digit-letter junctions, all-caps acronyms, or rely on the ad-hoc enum prefix toggle. Concretely:

• Sheet/file names with digit junctions normalize differently:
  • csv__bom__utf_8_bom.proto → csv__bom__utf8_bom.proto
  • excel__metasheet__merger_1.proto → excel__metasheet__merger1.proto
  • excel__metasheet__scatter_1.proto → excel__metasheet__scatter1.proto
• Field / enum value spellings inside generated protos shift to the STYLE2024 form (see updated golden files under test/functest/proto/default/*).
• EnumValueWithPrefix = false no longer suppresses the prefix; downstream users relying on the unprefixed form must regenerate.
• Removed strcase symbols (ToLowerCamel, ToKebab, ToDelimited, …): no internal user remains, but external embedders of internal/strcase (if any) need to migrate to the four supported conversions.

[codecov]

Codecov Report

❌ Patch coverage is 93.45794% with 21 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.09%. Comparing base (ffb15fb) to head (1307232).

Files with missing lines	Patch %	Lines
internal/strcase/camel.go	88.46%	5 Missing and 4 partials ⚠️
internal/protogen/sheet_mode.go	50.00%	3 Missing and 1 partial ⚠️
internal/protogen/exporter.go	76.92%	1 Missing and 2 partials ⚠️
internal/protogen/protogen.go	50.00%	1 Missing and 2 partials ⚠️
internal/strcase/enum_value.go	90.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #405      +/-   ##
==========================================
+ Coverage   74.83%   75.09%   +0.25%     
==========================================
  Files          88       90       +2     
  Lines        9372     9536     +164     
==========================================
+ Hits         7014     7161     +147     
- Misses       1785     1795      +10     
- Partials      573      580       +7     

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[wenchy]

Due to Edition 2024: features.enforce_naming_style

Values available:

STYLE2024: Enforces strict adherence to the style guide for naming.
STYLE_LEGACY: Applies the pre-Edition 2024 level of style guide enforcement.

So if tableau support the new naming style, it shoud be enabled by config options.

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf CI / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	May 27, 2026, 8:46 AM