Preserve the expected cgen path when the generated layer is absent

[brondani]

Fixes

• Running generator and creating a *.cgen.yml file does not refresh CMSIS View or diagnostics vscode-cmsis-solution#394

Changes

• Preserve the expected cgen path when a generated layer file is absent. The missing cgen is registered as a clayer before context processing returns an error. This allows the generated *.cbuild-idx.yml file to identify the missing generator output while conversion still fails with the existing diagnostic.
• Extended ExternalGenerator_NoCgenFile test case to verify that the missing cgen path is listed under clayers in the generated cbuild index.

Risk

Low. The successful generator-import path is unchanged; only missing cgen handling and its partial index output are affected.

Checklist

• 🤖 This change is covered by unit tests (if applicable).
• 🤹 Manual testing has been performed (if necessary).
• 🛡️ Security impacts have been considered (if relevant).
• 📖 Documentation updates are complete (if required).
• 🧠 Third-party dependencies and TPIP updated (if required).

[Copilot]

Pull request overview

This PR improves how projmgr reports missing external-generator output by keeping the expected *.cgen.yml path in the generated *.cbuild-idx.yml even when the generated layer file is absent, while still failing conversion with the existing diagnostic.

Changes:

• Register the missing generator-import (.cgen.yml) as a context clayer before returning failure so the cbuild index can surface the missing path.
• Adjust generated-layer processing to add the generator-import clayer to the context before failing.
• Extend the ExternalGenerator_NoCgenFile unit test to assert the missing cgen path appears under clayers in the generated cbuild index.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
tools/projmgr/src/ProjMgrExtGenerator.cpp	On missing cgen file, logs the error and stores the expected path so it can be emitted into the cbuild index.
tools/projmgr/src/ProjMgrWorker.cpp	Ensures the generator-import clayer is registered in the context before returning failure for missing cgen.
tools/projmgr/test/src/ProjMgrUnitTests.cpp	Verifies the missing cgen path is present in the generated extgen.cbuild-idx.yml under clayers.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[github-actions]

Test Results

  2 files   -    37   14 suites   - 107   14m 8s ⏱️ - 4m 31s
475 tests  -   451  475 ✅  - 434  0 💤  - 17  0 ❌ ±0 
950 runs   - 1 041  950 ✅  - 990  0 💤  - 51  0 ❌ ±0 

Results for commit 21fc875. ± Comparison against base commit 633c10f.

This pull request removes 451 tests.

AuxCmdTests ‑ MkdirCmdTest
AuxCmdTests ‑ RmdirCmdTest
AuxCmdTests ‑ TouchCmdTest
BuildSystemGeneratorTests ‑ GenAuditFile
BuildSystemGeneratorTests ‑ GenAuditFile_WithOut_Existing_Audit_File
BuildSystemGeneratorTests ‑ GenAuditFile_With_Existing_Audit_File
BuildSystemGeneratorTests ‑ GetString
BuildSystemGeneratorTests ‑ StrConv
BuildSystemGeneratorTests ‑ StrNorm
CBuildGCCTests ‑ Asm
…