Re: [PATCH] Ensure restore_term works correctly with DUPLEX

From: Phillip Wood <phillip.wood123@gmail.com>
Date: Jun 23, 2025, 09:42 UTC
Message-ID: <d6e22dba-637b-4b5d-bd88-25fa320e22ff@gmail.com>
In-Reply-To: <ckzjxolc5jthge62zcm5abnssefwntc3ryu6sumpvrdontmyyq@d4ahvg5umked>

On 19/06/2025 00:43, Carlo Marcelo Arenas Belón wrote:

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> On Thu, Jun 19, 2025 at 08:38:29AM -0800, James Duley wrote:
>> On Wed, 18 Jun 2025 at 22:07, Carlo Marcelo Arenas Belón
>> <carenas@gmail.com> wrote:
>>>
>> I thought about something like that, but I figured:
>> * restore_term is only called if save_term is successful
>> * hconout is always invalid before save_term is called
> 
> but it is not always set to invalid at the end of restore_term()
> so it can't be relied upon either.

Are you sure about that? It looks to me like the only time we don't reset hconout is when we use stty in which case I think hconout is already set to the invalid handle value.

>> * 0 might be a valid cmode_out that should be restored
> 
> cmode_out == 0 is not a valid mode that should be restored,

cmode_out is a bitfield. The documentation for SetConsoleMode() says the mode parameter "can be one or more of the following values" which implies zero is not a valid mode. It seems very hacky to be relying on that when we can just check if the output handle is valid though.

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> and
> indeed the original code was (ab)using that fact to decide if
> SetConsoleMode(hcounout) would be called at all (as a proxy to
> know if DUPLEX was used or not), hence why it is a bug not to
> update it, as you pointed out and found unexpectally, sorry
> about that.
> 
>> This is my first patch so I didn't realize git-for-windows had a
>> separate fork. That makes sense now because I couldn't find where
>> save_term was called from in this repo. To test this works I had
>> downloaded the artifacts from
>> https://github.com/git/git/actions/runs/15692373534/job/44210362705
>> but is that right? If I should submit this patch to the git-for-windows
>> fork, please let me know. Or, if someone, who knows what they're
>> doing, wants to pick this up, they're more than welcome.
> 
> You are going to need to get the Git for Windows SDK installed to
> be able to apply this patch and build your own version of GfW.
> 
> IMHO getting the change that makes "cmode_out" reliable again (which
> would include both our changes) should be a good start regardless,
> and at least that change could be submitted here.

Yes, this change should absolutely be submitted here as it is fixing code that is upstream of git-for-windows.

Thanks

Phillip

> 
> Carlo
>