port & root

[Rainer Müller]

On 2018-04-05 19:39, Joshua Root wrote:
> On 2018-4-6 03:25 , Rainer Müller wrote:
>> On 2018-04-05 19:14, Joshua Root wrote:
>>> My guess is that this is a bug in Tcl's file command. Deleting a
>>> nonexistent file is not supposed to be considered an error. But by
>>> starting two instances of port(1) at the same time, a race condition
>>> arises. The 'file delete' command probably checks whether the file
>>> exists, returns TCL_OK if not, and then attempts to delete the file. If
>>> the file has been deleted by the other running instance (or indeed
>>> anything else) between these two steps, then the actual deletion fails,
>>> and it incorrectly returns an error.
>>
>> You are right. We hit a race condition in the implementation of 'file
>> delete' in Tcl.
>>
>> It is missing another check for ENOENT here, as done in line 381:
>>
>> https://github.com/macports/macports-base/blob/4b13207d9f7f9aba1cc9eba266b3071318637a8c/vendor/tcl8.5.19/generic/tclFCmd.c#L415
> 
> Still seems broken in 8.6 at first glance too.

I filed a patch with Tcl upstream:
https://core.tcl.tk/tcl/tktview?name=27b6822849

Rainer