NET-589 Create rule S7131: You should not release a write lock when a read lock has been acquired and vice versa

rules/S7131/csharp/metadata.json

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+{
+  "title": "You should not release a write lock when a read lock has been acquired",
+  "type": "BUG",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "1h"
+  },
+  "tags": [
+  ],
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-7131",
+  "sqKey": "S7131",
+  "scope": "All",
+  "defaultQualityProfiles": ["Sonar way"],
+  "quickfix": "infeasible",
+  "code": {
+    "impacts": {
+      "RELIABILITY": "HIGH"
+    },
+    "attribute": "LOGICAL"
+  }
+}

rules/S7131/csharp/rule.adoc

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+
+When using https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlock[ReaderWriterLock] and https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim[ReaderWriterLockSlim] for managing read and write locks, you should not release a read lock while holding a write lock and vice versa, otherwise you might have unexpected behavior.
+The locks should be always correctly paired so that the shared resource is accessed safely.
+
+This rule raises if:
+
+* you acquire https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlock.acquirewriterlock[ReaderWriterLock.AcquireWriterLock] or https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlock.upgradetowriterlock[ReaderWriterLock.UpgradeToWriterLock] and then use https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlock.releasereaderlock[ReaderWriterLock.ReleaseReaderLock] before releasing the writerlock
+* you acquire https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim.enterwritelock[ReaderWriterLockSlim.EnterWriteLock] or https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim.tryenterwritelock[ReaderWriterLockSlim.TryEnterWriteLock] and then use https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim.exitreadlock[ReaderWriterLockSlim.ExitReadLock] before you release it
+* you acquire https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlock.acquirereaderlock[ReaderWriterLock.AcquireReaderLock] or https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlock.downgradefromwriterlock[ReaderWriterLock.DowngradeFromWriterLock] and then use https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlock.releasewriterlock[ReaderWriterLock.ReleaseWriterLock] before releasing the reader lock
+* or you acquire https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim.enterreadlock[ReaderWriterLockSlim.EnterReadLock], https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim.tryenterreadlock[ReaderWriterLockSlim.TryEnterReadLock], https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim.enterupgradeablereadlock[ReaderWriterLockSlim.EnterUpgradeableReadLock] or https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim.tryenterupgradeablereadlock[ReaderWriterLockSlim.TryEnterUpgradeableReadLock] and then use https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim.exitwritelock[ReaderWriterLockSlim.ExitWriteLock] before you release it.
+
+
+== Why is this an issue?
+
+If you use the `ReaderWriterLockSlim` class, you will get a https://learn.microsoft.com/en-us/dotnet/api/system.threading.lockrecursionexception[lockrecursionexception].
+In the case of `ReaderWriterLock`, you'll get a runtime exception for trying to release a lock that is not owned by the calling thread.
+
+
+=== Code examples
+
+==== Noncompliant code example
+
+[source,csharp,diff-id=1,diff-type=noncompliant]
+----
+class Example
+{
+    private static ReaderWriterLock rwLock = new ReaderWriterLock();
+    private static int sharedResource = 0;
+
+    static void Writer()
+    {
+        try
+        {
+            rwLock.AcquireWriterLock(2000);
+            sharedResource++;
+        }
+        finally
+        {
+            rwLock.ReleaseReaderLock(); // Noncompliant, will throw runtime exception
+            rwLock.ReleaseWriterLock();
+        }
+    }
+
+    static void Reader()
+    {
+        try
+        {
+            rwLock.AcquireReaderLock(2000);
+        }
+        finally
+        {
+            rwLock.ReleaseWriterLock(); // Noncompliant, will throw runtime exception
+            rwLock.ReleaseReaderLock();
+        }
+    }
+}
+----
+
+==== Compliant solution
+
+[source,csharp,diff-id=1,diff-type=compliant]
+----
+class Example
+{
+    private static ReaderWriterLock rwLock = new ReaderWriterLock();
+    private static int sharedResource = 0;
+
+    static void Writer()
+    {
+        try
+        {
+            rwLock.AcquireWriterLock(2000);
+            sharedResource++;
+        }
+        finally
+        {
+            rwLock.ReleaseWriterLock();
+        }
+    }
+
+    static void Reader()
+    {
+        try
+        {
+            rwLock.AcquireReaderLock(2000);
+        }
+        finally
+        {
+            rwLock.ReleaseReaderLock();
+        }
+    }
+}
+----
+
+== Resources
+
+=== Documentation
+
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlock[ReaderWriterLock Class]
+* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/api/system.threading.readerwriterlockslim[ReaderWriterLockSlim]
+
+include::../rspecator.adoc[]

rules/S7131/message.adoc

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+=== Message
+
+You should not release this xxx lock as a xxx lock has been acquired.
+

rules/S7131/metadata.json

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+{
+}

rules/S7131/rspecator.adoc

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+ifdef::env-github,rspecator-view[]
+
+'''
+== Implementation Specification
+(visible only on this page)
+
+include::message.adoc[]
+
+endif::env-github,rspecator-view[]