Merge branch 'main' into fix/set-intersect-perf-final

Author: aw0lid

.github/copilot-instructions.md

@@ -20,11 +20,17 @@ Bootstrap contamination: early commits break compiler → later "fixes" still us
 ## Test
 
 Default: `-c Debug`
+
 Use `-c Release` for: EmittedIL tests, Optimizer tests, full component runs
-spot check: `dotnet test <proj> --filter "Name~X" -c Debug`
+
+spot check: `dotnet test <proj> [--filter-method|--filter-class] "<glob_pattern>" -c Debug`
+
 full component: `dotnet test tests/FSharp.Compiler.ComponentTests -c Release`
+
 IDE/service: `tests/FSharp.Compiler.Service.Tests`
+
 VS integration: `vsintegration/` (Windows only)
+
 update baselines: `TEST_UPDATE_BSL=1 <test command>`
 
 ## Spotcheck tests

.github/instructions/TypedTreePickle.instructions.md

@@ -67,7 +67,7 @@ It tests both directions:
 
 Also run the import regression tests:
 ```bash
-dotnet test tests/FSharp.Compiler.ComponentTests -c Release --filter "FullyQualifiedName~Import" /p:BUILDING_USING_DOTNET=true
+dotnet test tests/FSharp.Compiler.ComponentTests -c Release -- --filter-method "*Import*" /p:BUILDING_USING_DOTNET=true
 ```
 
 For a detailed example of what goes wrong when these rules are violated, see `docs/postmortems/regression-fs0229-bstream-misalignment.md`.

.github/skills/hypothesis-driven-debugging/SKILL.md

@@ -33,7 +33,7 @@ Before forming hypotheses, create the smallest possible reproduction:
 1. **Extract the failure**:
    ```bash
    # For test failures - run just the failing test
-   dotnet test --filter "FullyQualifiedName~YourTest"
+   dotnet test -- --filter-method "*YourTest*"
 
    # For build failures - try to isolate the problematic file
    # Create a minimal .fs file that reproduces the issue
@@ -49,7 +49,7 @@ Before forming hypotheses, create the smallest possible reproduction:
    ## Minimal Reproduction
 
    File: test-case.fs
-   Command: dotnet test --filter "FullyQualifiedName~TestName"
+   Command: dotnet test -- --filter-method "*TestName*"
    Expected: <expected behavior>
    Actual: <actual behavior>
    ```
@@ -170,7 +170,7 @@ Brief description of the failure/bug being investigated.
 2. **Run affected tests**:
    ```bash
    # For targeted testing
-   dotnet test --filter "FullyQualifiedName~AffectedTestSuite"
+   dotnet test -- --filter-class "*AffectedTestSuite*"
 
    # Record: Passed, Failed, Skipped, Time
    ```
@@ -190,7 +190,7 @@ Brief description of the failure/bug being investigated.
    - Errors: 0
 
    Tests:
-   - Command: dotnet test --filter "FullyQualifiedName~XmlDocTests"
+   - Command: dotnet test -- --filter-class "*XmlDocTests*"
    - Total: 61
    - Passed: 56
    - Failed: 0
@@ -205,7 +205,7 @@ Brief description of the failure/bug being investigated.
 
 ```bash
 # 1. Observe failure
-dotnet test --filter "FullyQualifiedName~XmlDocTests"
+dotnet test -- --filter-class "*XmlDocTests*"
 # Result: 15 tests failing
 
 # 2. Create minimal repro
@@ -234,7 +234,7 @@ dotnet fsc test-case.fs
 ./build.sh -c Release
 # 4m 44.9s, 0 errors
 
-dotnet test --filter "FullyQualifiedName~XmlDocTests"
+dotnet test -- --filter-class "*XmlDocTests*"
 # 61 total, 56 passed, 0 failed, 5 skipped, 2s
 
 # 7. Verify minimal repro

.github/skills/pr-build-status/SKILL.md

@@ -1,62 +1,177 @@
 ---
 name: pr-build-status
-description: "Retrieve Azure DevOps build information for GitHub Pull Requests, including build IDs, stage status, and failed jobs."
+description: "Retrieve and analyze Azure DevOps build failures for GitHub PRs. Use when CI fails. CRITICAL: Collect ALL errors from ALL platforms FIRST, write hypotheses to file, then fix systematically."
 metadata:
   author: dotnet-maui
-  version: "1.0"
+  version: "2.0"
 compatibility: Requires GitHub CLI (gh) authenticated with access to dotnet/fsharp repository.
 ---
 
 # PR Build Status Skill
 
-Retrieve Azure DevOps build information for GitHub Pull Requests.
+Retrieve and systematically analyze Azure DevOps build failures for GitHub PRs.
 
-## Tools Required
+## CRITICAL: Collect-First Workflow
 
-This skill uses `bash` together with `pwsh` (PowerShell 7+) to run the PowerShell scripts. No file editing or other tools are required.
+**DO NOT push fixes until ALL errors are collected and reproduced locally.**
 
-## When to Use
+LLMs tend to focus on the first error found and ignore others. This causes:
+- Multiple push/wait/fail cycles
+- CI results being overwritten before full analysis
+- Missing platform-specific failures (Linux vs Windows vs MacOS)
 
-- User asks about CI/CD status for a PR
-- User asks about failed checks or builds
-- User asks "what's failing on PR #XXXXX"
-- User wants to see test results
+### Mandatory Workflow
+
+```
+1. COLLECT ALL     → Get errors from ALL jobs across ALL platforms
+2. DOCUMENT        → Write CI_ERRORS.md with hypotheses per platform
+3. REPRODUCE       → Run each failing test LOCALLY (in isolation!)
+4. FIX             → Fix each issue, verify locally
+5. PUSH            → Only after ALL issues verified fixed
+```
 
 ## Scripts
 
 All scripts are in `.github/skills/pr-build-status/scripts/`
 
 ### 1. Get Build IDs for a PR
-```bash
+```powershell
 pwsh .github/skills/pr-build-status/scripts/Get-PrBuildIds.ps1 -PrNumber <PR_NUMBER>
 ```
 
-### 2. Get Build Status
-```bash
+### 2. Get Build Status (List ALL Failed Jobs)
+```powershell
+# Get overview of all stages and jobs
 pwsh .github/skills/pr-build-status/scripts/Get-BuildInfo.ps1 -BuildId <BUILD_ID>
-# For failed jobs only:
+
+# Get ONLY failed jobs (use this to see all failing platforms)
 pwsh .github/skills/pr-build-status/scripts/Get-BuildInfo.ps1 -BuildId <BUILD_ID> -FailedOnly
 ```
 
 ### 3. Get Build Errors and Test Failures
-```bash
-# Get all errors (build errors + test failures)
+```powershell
+# Get ALL errors (build errors + test failures) - USE THIS FIRST
 pwsh .github/skills/pr-build-status/scripts/Get-BuildErrors.ps1 -BuildId <BUILD_ID>
 
-# Get only build/compilation errors
-pwsh .github/skills/pr-build-status/scripts/Get-BuildErrors.ps1 -BuildId <BUILD_ID> -ErrorsOnly
+# Filter to specific job (after getting overview)
+pwsh .github/skills/pr-build-status/scripts/Get-BuildErrors.ps1 -BuildId <BUILD_ID> -JobFilter "*Linux*"
+pwsh .github/skills/pr-build-status/scripts/Get-BuildErrors.ps1 -BuildId <BUILD_ID> -JobFilter "*Windows*"
+pwsh .github/skills/pr-build-status/scripts/Get-BuildErrors.ps1 -BuildId <BUILD_ID> -JobFilter "*MacOS*"
+```
+
+### 4. Direct API Access (for detailed logs)
+```powershell
+# Get timeline with all jobs
+$uri = "https://dev.azure.com/dnceng-public/public/_apis/build/builds/<BUILD_ID>/timeline?api-version=7.1"
+Invoke-RestMethod -Uri $uri | Select-Object -ExpandProperty records | Where-Object { $_.result -eq "failed" }
 
-# Get only test failures
-pwsh .github/skills/pr-build-status/scripts/Get-BuildErrors.ps1 -BuildId <BUILD_ID> -TestsOnly
+# Get specific log content
+$logUri = "https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_apis/build/builds/<BUILD_ID>/logs/<LOG_ID>"
+Invoke-RestMethod -Uri $logUri | Select-String "Failed|Error|FAIL"
 ```
 
-## Workflow
+## Step-by-Step Analysis Procedure
+
+### Step 1: Get Failed Build ID
+```powershell
+pwsh .github/skills/pr-build-status/scripts/Get-PrBuildIds.ps1 -PrNumber XXXXX
+# Note the BuildId with FAILED state
+```
 
-1. Get build IDs: `scripts/Get-PrBuildIds.ps1 -PrNumber XXXXX`
-2. For each build, get status: `scripts/Get-BuildInfo.ps1 -BuildId YYYYY`
-3. For failed builds, get error details: `scripts/Get-BuildErrors.ps1 -BuildId YYYYY`
+### Step 2: List ALL Failed Jobs (Cross-Platform!)
+```powershell
+pwsh .github/skills/pr-build-status/scripts/Get-BuildInfo.ps1 -BuildId YYYYY -FailedOnly
+```
+**IMPORTANT**: Note jobs from EACH platform:
+- Linux jobs
+- Windows jobs  
+- MacOS jobs
+- Different test configurations (net10.0 vs net472, etc.)
+
+### Step 3: Get Errors Per Platform
+```powershell
+# Collect errors from EACH platform separately
+pwsh .github/skills/pr-build-status/scripts/Get-BuildErrors.ps1 -BuildId YYYYY -JobFilter "*Linux*"
+pwsh .github/skills/pr-build-status/scripts/Get-BuildErrors.ps1 -BuildId YYYYY -JobFilter "*Windows*"
+pwsh .github/skills/pr-build-status/scripts/Get-BuildErrors.ps1 -BuildId YYYYY -JobFilter "*MacOS*"
+```
+
+### Step 4: Write CI_ERRORS.md
+Create a file in session workspace with ALL findings:
+```markdown
+# CI Errors for PR #XXXXX - Build YYYYY
+
+## Failed Jobs Summary
+| Platform | Job Name | Error Type |
+|----------|----------|------------|
+| Linux    | ...      | Test       |
+| Windows  | ...      | Test       |
+
+## Hypothesis Per Platform
+
+### Linux/MacOS Failures
+- Error: "The type 'int' is not defined"
+- Hypothesis: Missing FSharp.Core reference in test setup
+- Reproduction: `dotnet test ... -f net10.0`
+
+### Windows Failures  
+- Error: "Expected cache hits for generic patterns"
+- Hypothesis: Flaky test assertion, passes with other tests
+- Reproduction: `dotnet test ... --filter "FullyQualifiedName~rigid generic"`
+
+## Reproduction Commands
+...
+
+## Fix Verification Checklist
+- [ ] Linux error reproduced locally
+- [ ] Windows error reproduced locally
+- [ ] Fix verified for Linux
+- [ ] Fix verified for Windows
+- [ ] Tests run IN ISOLATION (not just with other tests)
+```
+
+### Step 5: Reproduce Locally BEFORE Fixing
+```powershell
+# Run failing tests IN ISOLATION (critical!)
+dotnet test ... --filter "FullyQualifiedName~FailingTestName" -f net10.0
+
+# Run multiple times to check for flakiness
+for ($i = 1; $i -le 3; $i++) { dotnet test ... }
+```
+
+### Step 6: Fix and Verify
+Only after ALL issues reproduced:
+1. Fix each issue
+2. Verify each fix locally (run test in isolation!)
+3. Run full test suite
+4. Check formatting
+5. THEN push
+
+## Common Pitfalls
+
+### ❌ Mistake: Focus on First Error Only
+```
+See Linux error → Fix → Push → Wait → See Windows error → Fix → Push → ...
+```
+
+### ✅ Correct: Collect All First
+```
+See Linux error → See Windows error → See MacOS error → Document all → 
+Fix all → Verify all locally → Push once
+```
+
+### ❌ Mistake: Run Tests Together
+```
+dotnet test ... --filter "OverloadCacheTests"  # All 8 pass together
+```
+
+### ✅ Correct: Run Tests in Isolation
+```
+dotnet test ... --filter "FullyQualifiedName~specific test name"  # May fail alone!
+```
 
 ## Prerequisites
 
 - `gh` (GitHub CLI) - authenticated
-- `pwsh` (PowerShell 7+)
+- `pwsh` (PowerShell 7+)
+- Local build environment matching CI