catch situations where PKGMAN_Exec returns fail

[ThomasBreuer]

InstallPackageFromGit( url ) calls PKGMAN_Exec, and expects that the result is a record.
Thus GAP runs into an error if PKGMAN_Exec returns fail.

[mtorpey]

Thanks for this! I guess this will be an easy fix.

[mtorpey]

Actually when looking into this, I'm having trouble reproducing the issue. Do you know of a common time when PKGMAN_Exec returns fail?

[fingolfin]

Does it handle case were git is not present on the user's machine? What happens if git is given an invalid URL (i.e. serves a 404; or serves an "access denied") ?

[ThomasBreuer]

The problem was indeed with git, but it was more subtle.
It disappears if one uses PathSystemProgram instead of Filename and DirectoriesSystemPrograms, see issue gap-system/gap/issues/5752 and the solution gap-system/gap/pull/5754.

[fingolfin]

So what shall we do then? Change PKGMAN_Exec to use PathSystemProgram if available (and otherwise fall back to existing code) ? Or should it also be changed to return a boolean? Or what?

[ThomasBreuer]

Actually the problem was fixed with #126, thus the issue can be closed.

As soon as PathSystemProgram becomes available in GAP, the code duplication can be removed, but that is another topic.