Fix bugs, remove dead code, upgrade to net8.0, add unit tests

[Copilot]

Multiple bugs and code quality issues identified in code review across Program.cs, Crawler.cs, Assembly.cs, and AssemblyExtension.cs. Also upgrades the project from EOL net6.0 to net8.0 and adds a unit test suite.

Bugs

• Program.cs: Fixed misleading error message for unexpected args; wired up unused path param in InnerLoop() to auto-parse on startup; fixed "itemsfound" typo; removed dead "s" menu case and its no-op CreateSymLinkForAssembly() body; changed FileMode.OpenOrCreate → FileMode.Create to prevent stale file content
• Crawler.cs: Fixed shallow dict copy losing OrdinalIgnoreCase comparer — new Dictionary<...>(sortedAssemblies_all, StringComparer.OrdinalIgnoreCase); added break after Remove(key) in inner loop to prevent KeyNotFoundException on continued iteration

Code Quality

• Assembly.cs: Added readonly to FileSize, PublicKeyToken, FrameworkVersion, IsManaged; removed unused using System.Security.Cryptography; removed dead /* NOTES */ C/C++ block; added Debug.WriteLine to swallowed catch in GetAssemblyName(); removed dead IsReadyToRun() (always false) and unreachable GetPublicKey()
• Crawler.cs / AssemblyExtension.cs: Removed unused using System.Text / using System.Threading.Tasks; use .Count property on materialized List<T> instead of .Count() LINQ; removed all dead commented-out CreateSymlinks, constants, and helper methods
• AssemblyCrawler.csproj: Upgraded TargetFramework from net6.0 → net8.0; bumped System.Reflection.Metadata to 8.0.0

Unit Tests

Added src/AssemblyCrawler.Tests (xUnit, net8.0) covering:

• StringExtension.GetStableHashCode() — stability and collision avoidance
• AssemblyInfo — managed vs. non-managed construction, GetHashCode() consistency
• AssemblyExtension — IsManagedAssembly(), SortByHashCode() grouping
• Crawler — Crawl() populates counts, double-crawl guard, Sort() before crawl, .resources.dll exclusion

Original prompt

Code Review Fixes

Address the following issues found during code review of the assembly crawling code in pieandcakes/AssemblyCrawler. The source code lives under src/AssemblyCrawler/.

🔴 Bugs to Fix

1. Program.cs line 16 — Inverted argument check: if (args.Length > 0) rejects all arguments. The program takes no arguments and uses an interactive loop, so the check is backwards — it should reject when arguments are passed unexpectedly. Actually, since the program is fully interactive (no args needed), the error message "Argument count not correct" is misleading. Fix: if the intent is to accept zero arguments, keep the > 0 check but fix the error message to say something like "This program does not accept command-line arguments.". Alternatively, if a path argument should be supported, wire it up to InnerLoop.

2. Program.cs line 26 — path parameter in InnerLoop is unused: InnerLoop(string? path = null) accepts a path but never uses it. Either remove the parameter or wire it up so that if a path is provided, it auto-parses that directory.

3. Program.cs line 253 — Missing space in output: $"{keyItemCount} itemsfound..." should be $"{keyItemCount} items found...".

4. Program.cs line 133 — Hidden menu option "s": The "s" case for CreateSymLinkForAssembly() is handled in the switch but is not listed in the printed menu options. Since CreateSymLinkForAssembly() is entirely commented out (no-op), remove the dead "s" case from the switch.

5. Crawler.cs line 125 — Shallow copy of dictionary loses case-insensitive comparer: sortedAssemblies_managed = new Dictionary<...>(sortedAssemblies_all) creates a new dictionary using the default comparer instead of StringComparer.OrdinalIgnoreCase. Fix: pass the comparer explicitly, e.g. new Dictionary<string, Dictionary<string, List<AssemblyInfo>>>(sortedAssemblies_all, StringComparer.OrdinalIgnoreCase).

6. Crawler.cs lines 130-136 — Potential InvalidOperationException / KeyNotFoundException: When iterating sortedAssemblies_managed inner keys, if the first entry's IsManaged is false, the outer key is removed mid-iteration. But the inner foreach loop continues to access sortedAssemblies_managed[key] which was just removed. Fix: add a break after sortedAssemblies_managed.Remove(key) to exit the inner loop after removing the outer key.

🟡 Code Quality / Maintainability Fixes

7. Assembly.cs lines 47-51 — Inconsistent readonly on Lazy fields: FName, AName, AssemblyVersion, FileVersion are readonly, but FileSize, PublicKeyToken, FrameworkVersion, IsManaged are not, even though none are reassigned after construction. Add readonly to FileSize, PublicKeyToken, FrameworkVersion, and IsManaged.

8. Assembly.cs line 9 — Unused using: Remove using System.Security.Cryptography;.

9. Assembly.cs lines 12-37 — Large dead block comment: Remove the /* NOTES ... */ block of C/C++ pseudocode.

10. Assembly.cs line 95 — Empty catch block silently swallows exceptions: In GetAssemblyName(), add at minimum a Debug.WriteLine or similar so failures are not silently lost.

11. Assembly.cs line 186 — GetPublicKey() is never called: Remove the unused GetPublicKey() method.

12. Assembly.cs lines 166-183 — IsReadyToRun() always returns false: The body is entirely commented out. Remove this dead method.

13. Crawler.cs lines 61-62 — Unnecessary LINQ .Count() on materialized list: files is already a List<T>, so use .Count property instead of .Count() LINQ extension. For assemblyFiles, enumerate it once into a list first, then use .Count.

14. Crawler.cs lines 142-246 — Large blocks of commented-out code: Remove dead CreateSymlinks method, unused AssemblyCacheFolderName and PreCacheFileName constants, and unused CreateDirectoryIfNotExists and MakeSymLink methods (they are only used by the commented-out code).

15. Program.cs line 181 — FileMode.OpenOrCreate may leave stale data: Change to FileMode.Create so old content is truncated.

16. AssemblyExtension.cs lines 7-8 — Unused using statements: Remove using System.Text; and using System.Threading.Tasks;.

17. Crawler.cs lines 7-8 — Unused using statements: Remove using System.Text; and using System.Threading.Tasks;.

18. AssemblyCrawler.csproj — Targets outdated net6.0: .NET 6 is end-of-life. Update TargetFramework to net8.0 and update System.Reflection.Metadata package to the latest stable version compatible with net8.0.

🧪 Unit Tests

Add a new test project (e.g. src/AssemblyCrawler.Tests/AssemblyCrawler.Tests.csproj) using xUnit or MSTest. Add it to the solution file src/AssemblyCrawler.sln. Write tests covering the following:

• Crawler class:
  • Test that Crawl() on a valid directory populates AssemblyList, TotalFileCount, and TotalAssemblyCount.
  • Te...

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