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FesTransaction.Commit - Update event handlers NullReferenceException [DNET476] #466

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firebird-automations opened this issue Dec 19, 2012 · 9 comments
Closed

FesTransaction.Commit - Update event handlers NullReferenceException [DNET476] #466

firebird-automations opened this issue Dec 19, 2012 · 9 comments
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@cincuranet
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component: ado.net provider fix-version: 5.0.0.0 priority: major resolution: fixed/done type: bug

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@firebird-automations
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Submitted by: devvvy (devvvy)

Relate to DNET689

Attachments:
firebird_commit_nullref.patch

Votes: 1

Stack:
> FirebirdSql.Data.FirebirdClient.dll!FirebirdSql.Data.Client.Native.FesTransaction.Commit() Line 249 C#⁠
FirebirdSql.Data.FirebirdClient.dll!FirebirdSql.Data.FirebirdClient.FbTransaction.Commit() Line 169 + 0xc bytes C#⁠
...

I ran into a (System.NullReferenceException: Object reference not set to an instance of an object) from FesTransaction.Commit, and I have no clue what's happenning... as my code from BeginTransaction to Commit is not-threaded...

public void Commit()
{
this.CheckTransactionState();

		lock \(this\.db\)
		\{
			// Clear the status vector
			this\.ClearStatusVector\(\);

			int trHandle = this\.handle;

			db\.FbClient\.isc\_commit\_transaction\(this\.statusVector, ref trHandle\);

			this\.handle = trHandle;

			this\.db\.ParseStatusVector\(this\.statusVector\);

			this\.db\.TransactionCount\-\-;

			if \(this\.Update \!= null\)
			\{
                this\.Update\(this, new EventArgs\(\)\); <\-\- Blows up here, this\.Update == null\!?\!? Suspect this is a threading issue? Any idea how this happenned? \(Nothing in my code references FesTransaction\.Update and whole BeginTransaction/Commit is not\-threaded\)
			\}

			this\.state = TransactionState\.NoTransaction;
		\}
	\}
@firebird-automations
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Commented by: devvvy (devvvy)

I suspect I fixed the issue by putting a lock around all places where this.Transaction.Update is decremented and/or set to null:

lock (FirebirdSql.Data.Client.Native.FesTransaction.UpdateSyncRoot)
{
this.Transaction.Update -= this.TransactionUpdate;
this.TransactionUpdate = null;
}

And also in FesTransaction.Commit,

public void Commit()
{
...
lock (FirebirdSql.Data.Client.Native.FesTransaction.UpdateSyncRoot)
{
if (this.Update != null)
{
// CAUTION: I suspect there's some threading issue this.Update becomes null sometimes ...
this.Update(this, new EventArgs());
}
}
}
...
}

Can anyone confirm if this is a proper fix please? Thank you very much.

@firebird-automations
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Commented by: @cincuranet

Can you confirm the issue is still happening with latest version (3.x)?

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Commented by: devvvy (devvvy)

sorry i don't think i will have time to upgrade for coming few months.

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Commented by: Jean-Pierre Schober (jpschober)

I run into the same problem and can confirm that it still exists in release 3.0.2.
It seems to be a threading problem regarding the Update event handler. I have attached a patch that should fix this.

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Modified by: Jean-Pierre Schober (jpschober)

Attachment: firebird_commit_nullref.patch [ 12310 ]

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Modified by: @cincuranet

Link: This issue relate to DNET689 [ DNET689 ]

@firebird-automations
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Modified by: @cincuranet

status: Open [ 1 ] => In Progress [ 3 ]

@firebird-automations
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Modified by: @cincuranet

status: In Progress [ 3 ] => Resolved [ 5 ]

resolution: Fixed [ 1 ]

Fix Version: 5.0.5.0 [ 10760 ]

@firebird-automations
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Modified by: @cincuranet

Fix Version: 5.0.0.0 [ 10744 ]

Fix Version: 5.0.5.0 [ 10760 ] =>

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component: ado.net provider fix-version: 5.0.0.0 priority: major resolution: fixed/done type: bug
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