threads / discuss / 43327

Re: For all you darcs lovers: git-hunk-commit

Subject: Re: For all you darcs lovers: git-hunk-commit

## tl;dr

5 messages between Dec 5, 2006 and Dec 8, 2006.

replies: 4people: 3as markdown or json

Johannes Schindelin· Dec 5, 2006, 18:48 UTC · lore

For all you darcs lovers: git-hunk-commit

Hi,

I was inspired by Han-Wen. This script allows you to commit selected hunks from the current modifications.

It has two modes: darcs mode (--darcs) and normal mode (without arguments).

In darcs mode, all hunks are presented one by one, and you are asked if you want to commit this or not. If you make a mistake: ^C and back to start. I do not really know darcs, so this might not be how it works -- I did not find any good documentation how a "darcs record" looks like.

Normal mode shows you the list of modified files, and lets you choose one. Then it shows you how many hunks there are, and lets you pick one for inspection, after which you are asked if you want it or not.

Normal mode is chattier, but if you know which (of those thousands) hunk you want to commit, it is faster. Besides, it was easier to debug.

Note that this script uses no temporary files, but rather bash array variables.

Ciao, Dscho

#!/bin/bash

# Copyright (C) 2006 Johannes E. Schindelin # Distributed under the same license as git.

# Use this command to commit just a few hunks of the current output # of "git diff". For your security, it only works when the index matches # HEAD.

# ensure that this is a git repository . git-sh-setup

# the index must match the HEAD
if [ -n "$(git diff --index --name-only HEAD)" ]; then
	echo "The staging area (AKA index) is already dirty."
	exit 1
fi
# read the names of all modified files into the array "modified"
declare -a modified
filenr=1
while read -d $'\0' file; do
	modified[$filenr]="$file"
	filenr=$(($filenr+1))
done < <(git ls-files --modified -z)
if [ ${#modified[*]} = 0 ]; then
	echo "No modified files."
	exit 1
fi
declare -a hunks

# interactively show the hunks of a file and ask if they should be committed. # 1st parameter is the index into the modified file list. # 2nd parameter should be "true" for darcs mode, empty otherwise. # Darcs mode means that all hunks are presented one after another. # Normal mode means user can specify hunks interactively.

select_hunks () {
	local index=$1
	local darcs_mode=$2
	local filename=${modified[$index]}
	local -a diff
	local -a hunk_start
	local current_hunks=${hunks[$index]}
	local lineno
	local hunkno
	local action
	local i
	local active
	lineno=1
	hunkno=0
	while read line; do
		diff[$lineno]="$line"
		case "$line" in
		@@*)
			hunk_start[$hunkno]=$lineno
			hunkno=$(($hunkno+1))
			;;
		esac
		lineno=$(($lineno+1))
	done < <(git diff "$filename")
	hunk_start[$hunkno]=$lineno
	action=""
	while [ "$action" != commit -a "$action" != abort ]; do
		case "$darcs_mode" in
		'')
			echo
			echo "Current hunks: ($current_hunks) of $hunkno hunks"
			echo "To show (and decide on) a hunk type in the number."
			echo "To commit the current hunks, say 'commit', else 'abort'."
			echo
			echo -n "Your choice? "
			read action
			;;
		[1-9]*)
			darcs_mode=$(($darcs_mode+1))
			if [ $darcs_mode -gt $hunkno ]; then
				action=commit
			else
				action=$darcs_mode
			fi
			;;
		*)
			darcs_mode=1
			action=1
			;;
		esac
		case "$action" in
		c) action=commit;;
		q|a) action=abort;;
		commit|abort) ;;
		[1-9]*)
			echo
			for ((i=${hunk_start[$(($action-1))]}; i<${hunk_start[$action]}; i++)); do
				if [ -n "$darcs_mode" -a $i = ${hunk_start[0]} ]; then
					echo "File: $filename"
				fi
				echo ${diff[$i]}
			done | less -FS
			active=$(echo $current_hunks,$action | tr , '\n' | sort | uniq -u | tr '\n' , | sed -e "s/^,//" -e "s/,$//")
			if [ ${#active} -lt ${#current_hunks} ]; then
				i=yes
			else
				i=no
			fi
			echo
			while [ -n "$action" -a "$action" != yes -a "$action" != no -a -n "$action" ]; do
				echo -n "Commit this hunk (default is $i)? "
				read action
				case "$action" in
				y) action=yes;;
				n) action=no;;
				esac
			done
			if [ -n "$action" -a $i != "$action" ]; then
				current_hunks=$active
			fi
			;;
		*) echo "Unknown command: $action";;
		esac
	done
	if [ "$action" = commit ]; then
		hunks[$index]=$current_hunks
	fi
}

# Apply the hunks saved in the array hunks for the specified file. # This means that the diff is rewritten to skip the unwanted hunks.

apply_hunks () {
	local index=$1
	local filename=${modified[$index]}
	local -a current_hunks
	local lineno
	local lineno2
	local linediff
	local hunkno
	local i
	local active
	i=0
	while read hunkno; do
		current_hunks[$i]=$hunkno
		i=$(($i+1))
	done < <(echo ${hunks[$index]} | tr , '\n')
	linediff=0
	hunkno=0
	i=0
	active=true
	while read line
	do
		case "$line" in
		@@*)
			hunkno=$(($hunkno+1))
			if [ $hunkno = "${current_hunks[$i]}" ]; then
				active=true
				i=$(($i+1))
				if [ $linediff -ne 0 ]; then
					lineno=$(echo "$line" | sed "s/^.*+\([0-9]*\)[, ].*$/\1/")
					lineno2=$(($lineno+$linediff))
					line="$(echo "$line" | sed "s/+$lineno/+$lineno2/")"
				fi
			else
				active=
				lineno=$(echo "$line" | sed -n "s/^.*-[0-9]*,\([0-9]*\) .*$/\1/p")
				if [ -z "$lineno" ]; then
					lineno=1
				fi
				lineno2=$(echo "$line" | sed -n "s/^.*+[0-9]*,\([0-9]*\) .*$/\1/p")
				if [ -z "$lineno2" ]; then
					lineno2=1
				fi
				linediff=$(($linediff+$lineno-$lineno2))
			fi
			;;
		esac
		if [ -n "$active" ]; then
			echo "$line"
		fi
	done < <(git diff "$filename")
}

darcs_mode= case "$1" in --darcs) darcs_mode=true;; esac

IFS=''
action=
i=
while [ "$action" != commit -a "$action" != abort ]; do
	case "$darcs_mode" in
	'')
		echo
		for ((i=1; i<$filenr; i++)); do
			echo -n "$i ${modified[$i]}"
			if [ -n "${hunks[$i]}" ]; then
				echo " (${hunks[$i]})"
			else
				echo
			fi
		done | less -FS
		echo
		echo "To put one or more hunks of a file into the staging area (AKA"
		echo "index), type in the number of the file."
		echo "To commit, say 'commit', to abort, say 'abort'."
		echo
		echo -n "Your choice? "
		read action
		;;
	true)
		if [ -z "$i" ]; then
			i=1
		else
			i=$(($i+1))
		fi
		if [ $i -ge $filenr ]; then
			action=commit
		else
			action=$i
		fi
		;;
	esac
	case "$action" in
	c) action=commit;;
	q|a) action=abort;;
	commit|abort) ;;
	[0-9]*) select_hunks "$action" "$darcs_mode";;
	*) echo "Unknown command." ;;
	esac
done
if [ "$action" = commit ]; then
	for ((i=1; i<$filenr; i++)); do
		if [ -n "${hunks[$i]}" ]; then
			apply_hunks $i
		fi
	done | tee a123 | git apply --cached
	git commit
fi
Han-Wen Nienhuys· Dec 6, 2006, 00:19 UTC · re: Johannes Schindelin · lore
Johannes Schindelin escreveu:
> I was inspired by Han-Wen. This script allows you to commit selected hunks 
Wow!
> In darcs mode, all hunks are presented one by one, and you are asked if 
> you want to commit this or not. If you make a mistake: ^C and back to 
> start. I do not really know darcs, so this might not be how it works -- I 
> did not find any good documentation how a "darcs record" looks like.

This is the interactive interface for commits in Darcs. It uses the same interface for pushing and pulling, where I mostly use y/n/a/d but sometimes the other letters too.

**** Shall I record this change? (1/?) [ynWsfqadjkc], or ? for help: ? How to use record... y: record this patch n: don't record it w: wait and decide later, defaulting to no

s: don't record the rest of the changes to this file f: record the rest of the changes to this file

d: record selected patches, skipping all the remaining patches a: record all the remaining patches q: cancel record

j: skip to next patch k: back up to previous patch c: calculate number of patches h or ?: show this help

<Space>: accept the current default (which is capitalized) ****

If you want to get a feel for it, grab darcs and run
  darcs init
  echo hello > hello
  darcs add
  darcs record
  

For a really neat implementation of per-hunk commits, try running darcsum in Emacs

> done < <(git ls-files --modified -z)
> 	done < <(git diff "$filename")
> 	done < <(echo ${hunks[$index]} | tr , '\n')
am I running the wrong bash? it barf on this. Don't you mean $(echo ... )

Frankly, I am amazed that people write things in bash at all--I vowed never to write bash again a couple of years ago. If you start doing arrays and counting, wouldn't a more high-level language be suitable?

-- 
 Han-Wen Nienhuys - hanwen@xs4all.nl - http://www.xs4all.nl/~hanwen
Johannes Schindelin· Dec 6, 2006, 00:36 UTC · re: Han-Wen Nienhuys · lore
Hi,
On Wed, 6 Dec 2006, Han-Wen Nienhuys wrote:
Show 26 quoted lines
> This is the interactive interface for commits in Darcs. It uses the
> same interface for pushing and pulling, where I mostly use y/n/a/d but
> sometimes the other letters too.
> 
> 
> ****
> Shall I record this change? (1/?)  [ynWsfqadjkc], or ? for help: ?
> How to use record...
> y: record this patch
> n: don't record it
> w: wait and decide later, defaulting to no
> 
> s: don't record the rest of the changes to this file
> f: record the rest of the changes to this file
> 
> d: record selected patches, skipping all the remaining patches
> a: record all the remaining patches
> q: cancel record
> 
> j: skip to next patch
> k: back up to previous patch
> c: calculate number of patches
> h or ?: show this help
> 
> <Space>: accept the current default (which is capitalized)
> ****

All but "y" and "n" are unsupported in hunk-commit.bash... Do you use all of these?

> If you want to get a feel for it, grab darcs and run
I already grabbed darcs a long time ago. And run, I did.
Show 7 quoted lines
> > done < <(git ls-files --modified -z)
> 
> > 	done < <(git diff "$filename")
> 
> > 	done < <(echo ${hunks[$index]} | tr , '\n')
> 
> am I running the wrong bash? it barf on this. Don't you mean $(echo ... )

I hoped that I did not use a too new bash. Unfortunately, I seem to have been wrong. These constructs redirect the output of the command as input to the while loop, because

	bla | while ...; do blub; done

opens a subshell, so that all changes done in "blub" are lost as soon as the while loop is finished.

> Frankly, I am amazed that people write things in bash at all--I vowed 
> never to write bash again a couple of years ago.  If you start doing 
> arrays and counting, wouldn't a more high-level language be suitable?

Me, being one of the loudest proponents of C builtins on this list, I agree fully.

But in this case, bash was faster to script and debug, and unless people speak up, saying "I want that feature badly!", I do not plan to do anything with it.

Ciao, Dscho

Matthias Kestenholz· Dec 8, 2006, 08:55 UTC · re: Johannes Schindelin · lore
Hi,
On Wed, 2006-12-06 at 01:36 +0100, Johannes Schindelin wrote:
> But in this case, bash was faster to script and debug, and unless people 
> speak up, saying "I want that feature badly!", I do not plan to do 
> anything with it.

This feature is _very_ handy and I think it would be great if this became part of the default git distribution.

Thanks for writing this tool!
Matthias
Johannes Schindelin· Dec 8, 2006, 15:37 UTC · re: Matthias Kestenholz · lore
Hi,
On Fri, 8 Dec 2006, Matthias Kestenholz wrote:
Show 7 quoted lines
> On Wed, 2006-12-06 at 01:36 +0100, Johannes Schindelin wrote:
> > But in this case, bash was faster to script and debug, and unless people 
> > speak up, saying "I want that feature badly!", I do not plan to do 
> > anything with it.
> 
> This feature is _very_ handy and I think it would be great if this
> became part of the default git distribution.

Note that it requires a relatively new bash version ATM, because of the "while read line; do ...; done < <(cmd)" construct. I have another version which substitutes a temporary file for that, but I keep thinking that a graphical tool, such as git-gui, would be more appropriate. BTW I just did it in bash, because I wanted to learn about these famous bash arrays.

Ciao, Dscho

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