[Mono-dev] a set of tests to find out the difference between .Net and Mono implementation (Mono-devel-list Digest, Vol 113, Issue 25)

[Jo Shields]

On 16/09/14 12:31, Marek Safar wrote:
>> Linux, it's not. i do not think this is a Mono issue, but will it be better
>> to help set the execute permission if Process.Start calls a non-executable
>> file? or at least provide a more friendly exception, current the error
>> message is 'Cannot find the specified file', which is confusing.
>>
> We cannot just set the execution permission but reporting more useful
> exception is good idea. Could you fill bug/enhancement report for this.

There are a few use-cases to consider, if we want to automate any kind 
of best effort.

If you really mean to execute an ELF binary which lacks execute 
permissions, call "/lib/ld-linux.so.2 thing"

If you really mean to execute any kind of script (i.e. a file whose 
first two characters are "#!") then call "/bin/sh thing"

If you really mean to execute an arbitrary file 
(Process.Start("foo.xlsx") will open foo.xlsx in Excel, on Windows, for 
example) then call "/usr/bin/xdg-open thing" - this is probably the most 
useful use-case, and is also valid when thing is a URL, opening in the 
default browser.

Only after those three cases are exhausted unsuccessfully is "just throw 
an exception" the best option. We already recently gained support for 
Process.Start("monoassembly.exe") without needing binfmt-tools, which is 
handy. Of the three cases I listed above, I'd say #3 is quite important 
for user tools behaving in a coherent cross-platform manner, #2 is nice 
to have, and #1 is so unlikely to ever be needed as to be useless.