Re: [PATCH/RFC] Makefile: dedup list of files obtained from ls-files

[Ramsay Jones <ramsay@ramsayjones.plus.com>]

On 22/04/2019 15:49, Jeff King wrote:
> On Sun, Apr 21, 2019 at 10:19:04PM +0900, Junio C Hamano wrote:
> 
>>    I am not fan of adding the "| sort -u" of the whole thing,
>>    because there is no need to dedup the output of the $(FIND) side
>>    of the alternative, but "(ls-files | sort -u) || (find)" would
>>    obviously not work.  If we truly care, perhaps we should add a
>>    new option to ls-files to show each path only once, unless it is
>>    showing the stage number (i.e. "ls-files -s" or "ls-files -u"),
>>    but this gets the problem go away without code change, hence this
>>    RFC ;-)
> 
> FWIW, after reading your commit message my thoughts immediately turned
> to "why can't ls-files have a mode that outputs each just once", but
> then ended up at the same place as your patch: it's not that hard to
> just de-dup the output.

My immediate thought was "that is simply a bug, no?" :-D

I haven't used 'git ls-files' that much, so it's no great surprise
that I had not noticed it odd behaviour!

So, this evening, I decided to have a little play:

  $ git status
  On branch master
  You have unmerged paths.
    (fix conflicts and run "git commit")
    (use "git merge --abort" to abort the merge)
  
  Changes to be committed:
  
  	new file:   d
  
  Unmerged paths:
    (use "git add <file>..." to mark resolution)
  
  	both modified:   a
  
  Changes not staged for commit:
    (use "git add/rm <file>..." to update what will be committed)
    (use "git checkout -- <file>..." to discard changes in working directory)
  
  	modified:   b
  	deleted:    c
  
  Untracked files:
    (use "git add <file>..." to include in what will be committed)
  
  	e
  
  $ git ls-files
  a
  a
  a
  b
  c
  d
  $ git ls-files -c
  a
  a
  a
  b
  c
  d
  $ git ls-files -m
  a
  a
  a
  b
  c
  $ git ls-files -d
  c
  $ git ls-files -u
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  $ git ls-files -s
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  100644 4f2e6529203aa6d44b5af6e3292c837ceda003f9 0	b
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  100644 72ad562535b8551cdd6659e8fb6c7cf6830e6a07 0	d
  $ git ls-files -sd
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  100644 4f2e6529203aa6d44b5af6e3292c837ceda003f9 0	b
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  100644 72ad562535b8551cdd6659e8fb6c7cf6830e6a07 0	d
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  $ git ls-files -su
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  $ git ls-files -sm
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  100644 4f2e6529203aa6d44b5af6e3292c837ceda003f9 0	b
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  100644 72ad562535b8551cdd6659e8fb6c7cf6830e6a07 0	d
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  100644 4f2e6529203aa6d44b5af6e3292c837ceda003f9 0	b
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  $ git ls-files -sdu
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  $ git ls-files -sdum
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  100644 4f2e6529203aa6d44b5af6e3292c837ceda003f9 0	b
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  $ git ls-files -sdumo
  e
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  100644 4ef30bbfe26431a69c3820d3a683df54d688f2ec 1	a
  100644 af72a79d2a6bd4b252b0aca22dba9946f7eedf86 2	a
  100644 f8829dfb9bf82721903d239ef069fb5de395f3e7 3	a
  100644 4f2e6529203aa6d44b5af6e3292c837ceda003f9 0	b
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  100644 a296d0bb611188cabb256919f36bc30117cca005 0	c
  $ 

Er, ... well, I obviously don't have a clue how it is supposed
to work. This just looks broken to me. :(

> So the patch itself looks good to me (though I agree that Eric's
> suggestion to de-dup inside "make" is better still).

Agreed.

ATB,
Ramsay Jones