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feat: refresh diagnostics and CodeLens when cdk.out changes - #1630

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megha-narayanan merged 3 commits into
aws:feat/cdk-lspfrom
megha-narayanan:feat/explorer-cdkout-watcher
Jun 16, 2026
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feat: refresh diagnostics and CodeLens when cdk.out changes#1630
megha-narayanan merged 3 commits into
aws:feat/cdk-lspfrom
megha-narayanan:feat/explorer-cdkout-watcher

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@megha-narayanan megha-narayanan commented Jun 15, 2026

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The LSP currently reads cdk.out once at startup and never refreshes. After this PR, any
rewrite of cdk.out refreshes the editor's diagnostics and CodeLenses
automatically.

  • New lib/core/assembly-watcher.ts: a chokidar-backed watcher with a debounced
    200ms onChange, filtered to manifest.json, tree.json,
    validation-report.json. RWLock marker files (synth.lock,
    read.<pid>.<n>.lock) are excluded. Throws from onChange route through
    onError rather than leaking from the timer. Lives in lib/core/ so the web
    explorer can reuse it.
  • refreshFromAssembly is now the single fan-out for new assembly data:
    rebuild cachedIndex, publish empty diagnostics for URIs that no longer have
    violations (clearing resolved squiggles), republish current diagnostics, and
    send workspace/codeLens/refresh (gated on workspace.codeLens.refreshSupport).
  • When the validation report fails to load, last-good diagnostics are preserved,
    matching the existing contract for 'error' and 'not-found' reads.
  • Watcher started in onInitialized after the initial refresh, closed in
    onShutdown.
    Fixes #

Checklist

  • This change contains a major version upgrade for a dependency and I confirm all breaking changes are addressed
    • Release notes for the new version:

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

@megha-narayanan
feat(cdk-explorer): refresh diagnostics and CodeLens when cdk.out cha…
9cda94e 
…nges

The LSP read cdk.out once at startup and never refreshed. This PR makes
the editor live: any time cdk.out is rewritten (an external `cdk synth`,
`cdk watch`, or a future in-process synth), diagnostics and CodeLenses
update automatically.

* New `lib/core/assembly-watcher.ts`: a chokidar-backed watcher that fires
  a debounced (200ms) onChange when `manifest.json`, `tree.json`, or
  `validation-report.json` changes. RWLock marker files (`synth.lock`,
  `read.<pid>.<n>.lock`) are filtered out. Throws from onChange are
  forwarded to onError rather than leaking from the timer. The module is
  LSP-agnostic, ready for the future web server consumer.

* `refreshFromAssembly` is now the single 'new data -> all surfaces
  update' path: it rebuilds `cachedIndex`, publishes empty arrays for
  URIs that no longer have violations (so resolved squiggles disappear
  from the editor), republishes current diagnostics, and sends
  `workspace/codeLens/refresh` (gated on the client's
  `workspace.codeLens.refreshSupport` capability).

* When the validation report fails to load, last-good diagnostics are
  preserved instead of being wiped. This matches the existing contract
  for `'error'` and `'not-found'` reads.

* Watcher lifecycle: started in `onInitialized` after the initial
  refresh, closed in `onShutdown`.

Manual synth and auto-synth-on-save are deferred to follow-up PRs; this
PR delivers freshness for any external producer.

`chokidar@^4` is now a direct cdk-explorer dep (added via projen).
It was already in the bundled graph through toolkit-lib, so this is a
promotion, not a net-new bundled dependency.
@github-actions github-actions Bot added the p2 label Jun 15, 2026
@aws-cdk-automation
aws-cdk-automation requested a review from a team June 15, 2026 18:31
@megha-narayanan
refactor(cdk-explorer): use filename constants and drop unused violat…
46e55e5 
…ionsError

* Export `MANIFEST_FILE` from `cloud-assembly-api` (was private). Add
  `TREE_FILE` as a local export of `assembly-watcher.ts`. aws-cdk-lib's
  TreeMetadata hard-codes `tree.json` rather than importing a shared
  constant, so `TREE_FILE` is a consumer-side label only.

* Reader, watcher, fixtures, and tests now use the constants instead of
  repeating filename literals. Non-signal-file paths in the watcher test
  stay literal so they continue to exercise the rejection path.

* Drop `AssemblyData.violationsError` and the if-guard around the
  publish/clear loop. The producer writes `validation-report.json`
  synchronously, so a corrupt file is unreachable through normal synth
  flow. A failed load surfaces via the existing `warnings` array; the
  rare partial-write race resolves on the next watcher tick.
@megha-narayanan
megha-narayanan marked this pull request as ready for review June 15, 2026 19:29
@rix0rrr rix0rrr self-assigned this Jun 16, 2026
@megha-narayanan
Merge remote-tracking branch 'upstream/feat/cdk-lsp' into feat/explor…
a574f3e 
…er-cdkout-watcher

# Conflicts:
#	packages/@aws-cdk/cdk-explorer/test/lsp/server.test.ts
@megha-narayanan
megha-narayanan merged commit 5afd770 into aws:feat/cdk-lsp Jun 16, 2026
7 of 8 checks passed
@megha-narayanan
megha-narayanan deleted the feat/explorer-cdkout-watcher branch June 16, 2026 18:30
@megha-narayanan megha-narayanan mentioned this pull request Jun 16, 2026
Merged
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megha-narayanan added a commit to megha-narayanan/aws-cdk-cli that referenced this pull request Jun 22, 2026
@megha-narayanan
Merge upstream/feat/cdk-lsp into feat/explorer-path-containment
82242fa 
Integrates the aws#1630 cdk.out watcher with the async assembly read path. readAssembly and buildConstructTreeAsync stay async; the watcher onChange refreshes via the async path with its rejection routed to console.error. aws#1630's watcher tests now await the async refresh (triggerWatcher settles the fire-and-forget refresh), and the sync readAssembly test doubles were made async to match the Promise-only seam.
@megha-narayanan megha-narayanan mentioned this pull request Jun 29, 2026
Merged
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megha-narayanan added a commit that referenced this pull request Jun 30, 2026
@megha-narayanan
feat: synth triggering (#1634)
8762f7b 
Adds manual synth and auto-synth-on-save to the CDK LSP. The cdk.out
watcher (landed in #1630) handles all diagnostics/lens refreshes --
these commands just add new ways to produce a fresh assembly.

Features:
↻ Synth now CodeLens at the top of any CDK source file (only when
auto-synth is off)
▶ Enable auto-synth / ⏹ Disable auto-synth toggle
Auto-synth starts disabled
When auto-synth is on, saving any non-ignored file in the project
triggers a synth
All feedback/output goes to the Output panel, no popups

Design decisions (the important ones):

Concurrent synths are supressed: if a save fires during a slow synth,
that save is skipped. The next save picks it up.
cdk.json is read once at startup. Changing it requires an LSP restart.
The toggle/synth lenses only appear on files that already have L1
resource lenses. Files with no CDK resources see nothing.
Toggle state resets to disabled on LSP restart (not persisted).

NOTE: One thing not in this PR (but must land before prod) is a
workspace trust gate. We should verify with the user that they trust
this workspace before running any synth. I may need to set up some way
to preserve this between sessions.

Open questions / things I need some feedback on:
- Is "auto-synth" the right name? Alternatives: "synth on save", "live
synth"?
- Where should the toggle live? Line 0 of a CDK file works for LSP-only,
but it's only visible when you're in a file with constructs. Status bar
item would be better UX but needs a client extension. Is there a better
alternative?
- Should synth failures (app compile errors) be more visible than the
Output panel? A diagnostic on the first line of the failing file, for
example?
- If the app has context lookups and no cached cdk.context.json, synth
fails with an auth/context error. Should the error message detect this
and suggest running cdk synth in terminal first?

<img width="809" height="161" alt="Screenshot 2026-06-16 at 3 41 01 PM"
src="https://github.com/user-attachments/assets/b542927c-0206-462f-8464-2c43f19bbe0b"
/>
<img width="771" height="166" alt="Screenshot 2026-06-16 at 3 41 10 PM"
src="https://github.com/user-attachments/assets/52695e76-2e1d-4fc8-ada7-d1ce338512cf"
/>

### Checklist
- [ ] This change contains a major version upgrade for a dependency and
I confirm all breaking changes are addressed
  - Release notes for the new version:

---
By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache-2.0 license
fossamagna pushed a commit to fossamagna/aws-cdk-cli that referenced this pull request Jul 17, 2026
@megha-narayanan @github-actions @otaviomacedo
feat: integrate lsp feature branch (aws#1681)
c4e4ee9 
Merges the`feat/cdk-lsp' branch into `main`. The change is additive and
introduces no behavior change to existing CLI commands.

- New `@aws-cdk/cdk-explorer` package containing the Language Server
under `lib/lsp` (server, diagnostics, CodeLens, template locator,
position mapping).
- Extends `@aws-cdk/cloud-assembly-api` with two parsing modules
consumed by the server: `construct-tree.ts` (builds the construct tree
from a cloud assembly) and `template-ranges.ts` (resolves a logical ID
or property to its byte range in the template).

Capabilities (folds in aws#1559, aws#1593, aws#1592, aws#1617, aws#1624, aws#1630, aws#1631,
aws#1662, aws#1634, aws#1674):

- Diagnostics: surfaces synth errors and policy-validation violations in
the editor, mapped back to the source.
- Surfaces CFN resources and adds CodeLens navigation from a construct
to its template resource.
- Navigation between construct source and the synthesized template in
both directions.
- Live refresh: diagnostics and CodeLens update when `cdk.out` changes.
- Reads are constrained to the project directory, and template reads run
off the LSP event loop.

This PR is the server and parsing foundation. It does not add a shipped
CLI command or the web explorer.

### Checklist
- [ ] This change contains a major version upgrade for a dependency and
I confirm all breaking changes are addressed
  - Release notes for the new version:

---
By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache-2.0 license

---------

Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Otavio Macedo <288203+otaviomacedo@users.noreply.github.com>
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