Re: [PATCH] maint: fix alphabetical order in .gitignore

[Pádraig Brady]

On 01/11/2013 08:47 AM, Bernhard Voelker wrote:
> On 01/02/2013 04:02 PM, Bernhard Voelker wrote:
> > If insert_vc_ignore is the only place where .gitignore
> > is sorted, why not fix it there, i.e. use some way to
> > add an entry without sorting the file?
>
> I found out that bootstrap tries to add the just-generated
> file "ABOUT-NLS" to .gitignore - which is already there.
>
> But today, insert_sorted_if_absent() changes .gitignore
> not only when the given entry is missing, but even if just
> the ordering would change.
>
> The following patch changes this behavior, and now
> insert_sorted_if_absent() only adds the entry - well, sorted
> again - only if the line count would change.
>
> The second patch fixes the sorting of current .gitignore
> (as in my initial patch).
>
> WDYT?
>
> Have a nice day,
> Berny
>
>
> > From 99c50676d4109e767926e9aa766e6e536dd3a716 Mon Sep 17 00:00:00 2001
> From: Bernhard Voelker <address@hidden>
> Date: Fri, 11 Jan 2013 09:12:31 +0100
> Subject: [PATCH 1/2] build: avoid unnecessary sorting of .gitignore
>
> During bootstrap, files may be created which are already included
> in .gitignore, but the test to add such a file relied on the
> sort order. Now, it just adds such a new entry and thus only
> changes the file if the line count would change.
>
> * bootstrap (insert_sorted_if_absent): Instead of comparing the
> sorted new file with the original, the function compares the line
> count, and only in case of a difference, the given file is changed.
> ---
>   bootstrap |    9 ++++++---
>   1 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/bootstrap b/bootstrap
> index 61a9cbd..e00639b 100755
> --- a/bootstrap
> +++ b/bootstrap
> @@ -306,10 +306,13 @@ insert_sorted_if_absent() {
>     file=$1
>     str=$2
>     test -f $file || touch $file
> -  echo "$str" | sort_patterns - $file | cmp -s - $file > /dev/null \
> -    || { echo "$str" | sort_patterns - $file > $file.bak \
> -      && mv $file.bak $file; } \
> +  linesold=$(wc -l < $file)
> +  linesnew=$(echo "$str" | sort_patterns - $file | wc -l)
> +  if [ $linesold != $linesnew ] ; then
> +    { echo "$str" | sort_patterns - $file > $file.bak \
> +    && mv $file.bak $file; } \
>       || exit 1
> +  fi
>   }
>
>   # Adjust $PATTERN for $VC_IGNORE_FILE and insert it with

Thanks for following this up.

One issue is if there were existing duplicate entries
in .gitignore, then the counts would be inaccurate.
That might be guarded with something like:

  duplicate_entries=$(sort .gitignore | uniq -d)
  if [ "$duplicate_entries" ] ; then
    echo "Error: Duplicate entries in .gitignore: " $duplicate_entries >&2
    exit 1
  fi

BTW changes to bootstrap go through gnulib first
and are synced from there, so when this is sorted
(no pun intended) I'll propose it to gnulib too.

thanks,
Pádraig.

p.s. While this removes the sorted requirement, it still
sorts the file on insertion. That's not a new restriction
but it does mess up/preclude the use of comments and separator
lines in .gitignore. In future it might be better to
auto generate something like this at the top of .gitignore:

## Inserted by bootstrap ##
entry1
blank_line_after_last_entry

To do that, you'd also have to remove existing
entries in .gitignore corresponding to the above section.