fix(devcontainer): preserve readonly compose mounts

[heyarny]

Summary

• Preserve readonly and ro mount options when devcontainer mounts are converted into generated Docker Compose service volumes.
• Add coverage for compose-mode mount conversion so readonly and ro become read-only volumes while valued options like readonly=true remain unsupported.

Root Cause

config.Mount stores mount options that are not modeled directly in Other. The non-compose Docker path serializes those options back into the mount string, but the compose override path rebuilt ServiceVolumeConfig with only Type, Source, and Target, dropping readonly/ro before Docker Compose saw them.

Validation

• go test ./pkg/devcontainer/...

Fixes #766.

Summary by CodeRabbit

• Bug Fixes

  • Fixed Docker Compose configuration generation to preserve read-only mount intent. Mounts specified as readonly, ro, or readonly=true are now correctly marked as read-only in the generated service volumes.

• Tests

  • Added coverage validating that read-only mount options are retained across multiple formats and generate the expected volume ReadOnly settings.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 1c0d457a-e1e9-462c-b758-dbc815ddc728

📥 Commits

Reviewing files that changed from the base of the PR and between a8a4145 and 88f0444.

📒 Files selected for processing (2)

• pkg/devcontainer/compose.go
• pkg/devcontainer/compose_test.go

🚧 Files skipped from review as they are similar to previous changes (2)

• pkg/devcontainer/compose.go
• pkg/devcontainer/compose_test.go

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📝 Walkthrough

Walkthrough

generateDockerComposeUpProject in compose.go now sets ServiceVolumeConfig.ReadOnly for each mount by calling a new helper isReadOnlyMount, which checks mount.Other for "readonly" or "ro". A new test verifies all three common read-only option forms produce the correct ReadOnly values on the generated Compose volumes.

Changes

Read-only mount propagation for Docker Compose devcontainers

Layer / File(s)	Summary
Read-only mount detection and volume wiring pkg/devcontainer/compose.go	readOnlyMountOption constant defines "readonly" for option detection; isReadOnlyMount helper inspects mount.Other for "readonly" or "ro" tokens; generateDockerComposeUpProject calls isReadOnlyMount to populate ReadOnly on each ServiceVolumeConfig.
Test coverage for read-only mount option forms pkg/devcontainer/compose_test.go	TestGenerateDockerComposeUpProjectPreservesReadOnlyMountOptions exercises readonly, ro, and readonly=true option forms, asserting 3 volumes with the first two read-only and the third writable.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix(devcontainer): preserve readonly compose mounts' clearly summarizes the main change—preserving readonly mount options in Docker Compose devcontainer configurations.
Linked Issues check	✅ Passed	The PR fully addresses the requirements from issue #766 by implementing readonly mount option preservation and adding corresponding test coverage.
Out of Scope Changes check	✅ Passed	All changes are directly related to preserving readonly mount options during devcontainer mount conversion to Docker Compose ServiceVolumeConfig.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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