Re: [PATCH 7/7] submodule.c: correctly handle nested submodules in is_submodule_modified

[Jonathan Nieder <jrnieder@gmail.com>]

Junio C Hamano wrote:

> Shouldn't this done as part of 4/7 where is_submodule_modified()
> starts reading from the porcelain v2 output?  4/7 does adjust for
> the change from double question mark (porcelain v1) to a single one
> for untracked, but at the same time it needs to prepare for these
> 'u' (unmerged), '1' (normal modification) and '2' (mods with rename)
> to appear in the output, no?
>
> IOW, with 4/7 and 7/7 done as separate steps, isn't the system
> broken between these steps?

No.  Both before and after patch 4, this code has to determine two
details from a submodule:

 1. Does it have untracked files?
 2. Does it have any modifications to tracked files (including
    submodules)?

Using porcelain v1 format, (1) is represented by a "??" line and (2)
is represented by any other line. Using porcelain v2 format, (1) is
represented by a "u" line and (2) is represented by any other line.

So patch 4 does not intend to change behavior.

This patch 7 is trying to do something more subtle.  Suppose I have a
superproject 'parent', with a submodule 'parent/sub', which itself
contains a submodule 'parent/sub/subsub'.  Now suppose I run, from
within 'parent':

	echo hi >sub/subsub/stray-file

Both before and after patch 4, if I run "git status" from 'parent'
then I will learn that "sub" was modified.  "git status" within 'sub'
would tell me that "subsub" has an untracked file.

But from the end user's point of view, even when running in "parent",
what I want to know is that there is an untracked file.  Treating it
as a modification instead of untracked file is confusing and does
not answer the user's actual question.  That is what patch 7 tries to
fix.

In other words, patch 7 is about changing that list of two questions
from before.  Something like

 1. Does it or any submodule contained within it have untracked files,
    that I could add with "git add -N --recurse-submodules"?

 2. Does it or any submodule contained within it have modified files,
    that I could add with "git add -u --recurse-submodules"?

 3. Does it or any submodule contained within it have a changed HEAD,
    that I could also add with "git add -u --recurse-submodules"?

Question (3) didn't come up before because when there are no nested
submodules, the diff machinery answers it (saving us from getting the
answer from the status --porcelain we recurse to).

Thanks and hope that helps,
Jonathan