From: Paul-Sebastian Ungureanu Date: Thu, 28 Jun 2018 16:17:58 GMT Subject: Re: [PATCH v6 3/4] stash: convert branch to builtin Message-ID: <5677e7cd-a0f9-194c-a7bd-5eea48c56e3d@gmail.com> In-Reply-To: Hello, On 27.06.2018 21:39, Junio C Hamano wrote: > This is primarily because cmd_$foo() is designed to be replacement > of "main()" in usual programs---it is allowed to assume the global > variables it uses have their initial values and nobody cares the > state it leaves behind when it returns. Argument parser may flip > bits in file-scope static variables to record which options are > seen, assuming that these variables are initialized to all-zero, and > that assumption would not hold for the second call to cmd_$foo(), > etc. cmd_$foo() also is allowed to call die() when there is an > unrecoverable error condition in the context of carrying out $foo; a > scripted Porcelain that used $foo as a building block to implement a > larger operation (e.g. "stash" that used "checkout" to switch to a > different branch) may want to react to the failure and do something > extra (i.e. "git checkout || do something more"). > > Using run_command() interface would not cause any of these problems; > the subcommand will run in a clean environment, and the caller can > react to its failure. > Thank you a lot for this great explanation. When I will submit a new iteration, I will make sure to replace calls of `cmd_$foo()` with `run_command()` (or with API, if possible). Best regards, Paul Ungureanu