Re: [PATCH v2] exec: Print absolute paths for command location queries

On 6/13/26 02:47, Herbert Xu wrote:
> Kerin Millar <[email protected]> wrote:
>> POSIX requires that, when reporting the location of a utility found by
>> searching PATH (or one named with a slash), the pathname written by
>> type, command -v and command -V be absolute:
>>
>>     Executable utilities, regular built-in utilities, command_names
>>     including a <slash> character, and any implementation-provided
>>     functions that are found using the PATH variable [...] shall be
>>     written as absolute pathnames.
>>
>> Presently, dash fails to conform in this regard. Address this issue by
>> prefixing relative pathnames with the logical current working directory,
>> provided that it still resolves to the current directory, and with the
>> physical current working directory otherwise. If the current working
>> directory cannot be determined, print the relative pathname instead.
>>
>> Link: https://lore.kernel.org/dash/[email protected]/
>> Reported-by: Christoph Anton Mitterer <[email protected]>
>> Suggested-by: Harald van Dijk <[email protected]>
>> Signed-off-by: Kerin Millar <[email protected]>
>> ---
>> src/cd.c   | 40 ++++++++++++++++++++++++++++++++++++----
>> src/cd.h   |  1 +
>> src/exec.c | 30 ++++++++++++++++++++++++++----
>> 3 files changed, 63 insertions(+), 8 deletions(-)
> 
> Even bash doesn't do this:
> 
> $ bash -o posix -c 'cd /; command -v bin/bash'
> bin/bash
> $

You're overlooking the "that are found using the PATH variable" from the 
spec. Because you included a / in the command, it is not looked up from 
PATH. Modifying your test to make sure PATH is used, we can see that 
bash does do this in POSIX mode:

$ bash -c 'cd /; PATH=bin command -v bash'
bin/bash
$ bash -o posix -c 'cd /; PATH=bin command -v bash'
/bin/bash

Cheers,
Harald van Dijk