Fix pre-existing static constructor race

NinoFloris · NinoFloris · commit 33edcfd2665d · 2026-04-08T00:08:06.000+02:00
diff --git a/src/Npgsql/TypeMapping/GlobalTypeMapper.cs b/src/Npgsql/TypeMapping/GlobalTypeMapper.cs
@@ -48,12 +48,20 @@ internal IEnumerable<PgTypeInfoResolverFactory> GetPluginResolverFactories()
 
     internal void AddGlobalTypeMappingResolvers(PgTypeInfoResolverFactory[] factories, Func<PgTypeInfoResolverChainBuilder>? builderFactory = null, bool overwrite = false)
     {
-        // Good enough logic to prevent SlimBuilder overriding the normal Builder.
-        if (overwrite || factories.Length > _typeMappingResolvers.Length)
+        _lock.EnterWriteLock();
+        try
         {
-            _builderFactory = builderFactory;
-            _typeMappingResolvers = factories;
-            ResetTypeMappingCache();
+            // Prevent SlimBuilder from overriding the normal Builder.
+            if (overwrite || factories.Length > _typeMappingResolvers.Length)
+            {
+                _builderFactory = builderFactory;
+                _typeMappingResolvers = factories;
+                ResetTypeMappingCache();
+            }
+        }
+        finally
+        {
+            _lock.ExitWriteLock();
         }
     }
 
@@ -67,12 +75,15 @@ PgSerializerOptions TypeMappingOptions
     {
         get
         {
-            if (_typeMappingOptions is not null)
-                return _typeMappingOptions;
+            if (Volatile.Read(ref _typeMappingOptions) is { } options)
+                return options;
 
-            _lock.EnterReadLock();
+            _lock.EnterWriteLock();
             try
             {
+                if (_typeMappingOptions is not null)
+                    return _typeMappingOptions;
+
                 var builder = _builderFactory?.Invoke() ?? new();
                 builder.AppendResolverFactory(_userTypeMapper);
                 foreach (var factory in _pluginResolverFactories)
@@ -90,7 +101,7 @@ PgSerializerOptions TypeMappingOptions
             }
             finally
             {
-                _lock.ExitReadLock();
+                _lock.ExitWriteLock();
             }
         }
     }

Original file line number	Diff line number	Diff line change
`@@ -48,12 +48,20 @@ internal IEnumerable<PgTypeInfoResolverFactory> GetPluginResolverFactories()`
`48`	`48`
`49`	`49`	`internal void AddGlobalTypeMappingResolvers(PgTypeInfoResolverFactory[] factories, Func<PgTypeInfoResolverChainBuilder>? builderFactory = null, bool overwrite = false)`
`50`	`50`	`{`
`51`		`- // Good enough logic to prevent SlimBuilder overriding the normal Builder.`
`52`		`- if (overwrite \|\| factories.Length > _typeMappingResolvers.Length)`
	`51`	`+ _lock.EnterWriteLock();`
	`52`	`+ try`
`53`	`53`	`{`
`54`		`- _builderFactory = builderFactory;`
`55`		`- _typeMappingResolvers = factories;`
`56`		`- ResetTypeMappingCache();`
	`54`	`+ // Prevent SlimBuilder from overriding the normal Builder.`
	`55`	`+ if (overwrite \|\| factories.Length > _typeMappingResolvers.Length)`
	`56`	`+ {`
	`57`	`+ _builderFactory = builderFactory;`
	`58`	`+ _typeMappingResolvers = factories;`
	`59`	`+ ResetTypeMappingCache();`
	`60`	`+ }`
	`61`	`+ }`
	`62`	`+ finally`
	`63`	`+ {`
	`64`	`+ _lock.ExitWriteLock();`
`57`	`65`	`}`
`58`	`66`	`}`
`59`	`67`
`@@ -67,12 +75,15 @@ PgSerializerOptions TypeMappingOptions`
`67`	`75`	`{`
`68`	`76`	`get`
`69`	`77`	`{`
`70`		`- if (_typeMappingOptions is not null)`
`71`		`- return _typeMappingOptions;`
	`78`	`+ if (Volatile.Read(ref _typeMappingOptions) is { } options)`
	`79`	`+ return options;`
`72`	`80`
`73`		`- _lock.EnterReadLock();`
	`81`	`+ _lock.EnterWriteLock();`
`74`	`82`	`try`
`75`	`83`	`{`
	`84`	`+ if (_typeMappingOptions is not null)`
	`85`	`+ return _typeMappingOptions;`
	`86`	`+`
`76`	`87`	`var builder = _builderFactory?.Invoke() ?? new();`
`77`	`88`	`builder.AppendResolverFactory(_userTypeMapper);`
`78`	`89`	`foreach (var factory in _pluginResolverFactories)`
`@@ -90,7 +101,7 @@ PgSerializerOptions TypeMappingOptions`
`90`	`101`	`}`
`91`	`102`	`finally`
`92`	`103`	`{`
`93`		`- _lock.ExitReadLock();`
	`104`	`+ _lock.ExitWriteLock();`
`94`	`105`	`}`
`95`	`106`	`}`
`96`	`107`	`}`