maintainers/scripts/nix-diff.sh

   1 #!/usr/bin/env nix-shell
   2 #! nix-shell -i bash -p coreutils gnugrep gnused
   3
   4 ################################################################################
   5 # nix-diff.sh                                                                  #
   6 ################################################################################
   7 # This script "diffs" Nix profile generations.                                 #
   8 #                                                                              #
   9 # Example:                                                                     #
  10 ################################################################################
  11 # > nix-diff.sh 90 92                                                          #
  12 # + gnumake-4.2.1                                                              #
  13 # + gnumake-4.2.1-doc                                                          #
  14 # - htmldoc-1.8.29                                                             #
  15 ################################################################################
  16 # The example shows that as of generation 92 and since generation 90,          #
  17 # gnumake-4.2.1 and gnumake-4.2.1-doc have been installed, while               #
  18 # htmldoc-1.8.29 has been removed.                                             #
  19 #                                                                              #
  20 # The example above shows the default, minimal output mode of this script.     #
  21 # For more features, run `nix-diff.sh -h` for usage instructions.              #
  22 ################################################################################
  23
  24 usage() {
  25     cat <<EOF
  26 usage: nix-diff.sh [-h | [-p profile | -s] [-q] [-l] [range]]
  27 -h:         print this message before exiting
  28 -q:         list the derivations installed in the parent generation
  29 -l:         diff every available intermediate generation between parent and
  30             child
  31 -p profile: specify the Nix profile to use
  32             * defaults to ~/.nix-profile
  33 -s:         use the system profile
  34             * equivalent to: -p /nix/var/nix/profiles/system
  35 profile:    * should be something like /nix/var/nix/profiles/default, not a
  36               generation link like /nix/var/nix/profiles/default-2-link
  37 range:      the range of generations to diff
  38             * the following patterns are allowed, where A, B, and N are positive
  39               integers, and G is the currently active generation:
  40                 A..B => diffs from generation A to generation B
  41                 ~N   => diffs from the Nth newest generation (older than G) to G
  42                 A    => diffs from generation A to G
  43             * defaults to ~1
  44 EOF
  45 }
  46
  47 usage_tip() {
  48     echo 'run `nix-diff.sh -h` for usage instructions' >&2
  49     exit 1
  50 }
  51
  52 while getopts :hqlp:s opt; do
  53     case $opt in
  54         h)
  55             usage
  56             exit
  57             ;;
  58         q)
  59             opt_query=1
  60             ;;
  61         l)
  62             opt_log=1
  63             ;;
  64         p)
  65             opt_profile=$OPTARG
  66             ;;
  67         s)
  68             opt_profile=/nix/var/nix/profiles/system
  69             ;;
  70         \?)
  71             echo "error: invalid option -$OPTARG" >&2
  72             usage_tip
  73             ;;
  74     esac
  75 done
  76 shift $((OPTIND-1))
  77
  78 if [ -n "$opt_profile" ]; then
  79     if ! [ -L "$opt_profile" ]; then
  80         echo "error: expecting \`$opt_profile\` to be a symbolic link" >&2
  81         usage_tip
  82     fi
  83 else
  84     opt_profile=$(readlink ~/.nix-profile)
  85     if (( $? != 0 )); then
  86         echo 'error: unable to dereference `~/.nix-profile`' >&2
  87         echo 'specify the profile manually with the `-p` flag' >&2
  88         usage_tip
  89     fi
  90 fi
  91
  92 list_gens() {
  93     nix-env -p "$opt_profile" --list-generations \
  94         | sed -r 's:^\s*::' \
  95         | cut -d' ' -f1
  96 }
  97
  98 current_gen() {
  99     nix-env -p "$opt_profile" --list-generations \
 100         | grep -E '\(current\)\s*$' \
 101         | sed -r 's:^\s*::' \
 102         | cut -d' ' -f1
 103 }
 104
 105 neg_gen() {
 106     local i=0 from=$1 n=$2 tmp
 107     for gen in $(list_gens | sort -rn); do
 108         if ((gen < from)); then
 109             tmp=$gen
 110             ((i++))
 111             ((i == n)) && break
 112         fi
 113     done
 114     if ((i < n)); then
 115         echo -n "error: there aren't $n generation(s) older than" >&2
 116         echo " generation $from" >&2
 117         return 1
 118     fi
 119     echo $tmp
 120 }
 121
 122 match() {
 123     argv=("$@")
 124     for i in $(seq $(($#-1))); do
 125         if grep -E "^${argv[$i]}\$" <(echo "$1") >/dev/null; then
 126             echo $i
 127             return
 128         fi
 129     done
 130     echo 0
 131 }
 132
 133 case $(match "$1" '' '[0-9]+' '[0-9]+\.\.[0-9]+' '~[0-9]+') in
 134     1)
 135         diffTo=$(current_gen)
 136         diffFrom=$(neg_gen $diffTo 1)
 137         (($? == 1)) && usage_tip
 138         ;;
 139     2)
 140         diffFrom=$1
 141         diffTo=$(current_gen)
 142         ;;
 143     3)
 144         diffFrom=${1%%.*}
 145         diffTo=${1##*.}
 146         ;;
 147     4)
 148         diffTo=$(current_gen)
 149         diffFrom=$(neg_gen $diffTo ${1#*~})
 150         (($? == 1)) && usage_tip
 151         ;;
 152     0)
 153         echo 'error: invalid invocation' >&2
 154         usage_tip
 155         ;;
 156 esac
 157
 158 dirA="${opt_profile}-${diffFrom}-link"
 159 dirB="${opt_profile}-${diffTo}-link"
 160
 161 declare -a temp_files
 162 temp_length() {
 163     echo -n ${#temp_files[@]}
 164 }
 165 temp_make() {
 166     temp_files[$(temp_length)]=$(mktemp)
 167 }
 168 temp_clean() {
 169     rm -f ${temp_files[@]}
 170 }
 171 temp_name() {
 172     echo -n "${temp_files[$(($(temp_length)-1))]}"
 173 }
 174 trap 'temp_clean' EXIT
 175
 176 temp_make
 177 versA=$(temp_name)
 178 refs=$(nix-store -q --references "$dirA")
 179 (( $? != 0 )) && exit 1
 180 echo "$refs" \
 181     | grep -v env-manifest.nix \
 182     | sort \
 183           > "$versA"
 184
 185 print_tag() {
 186     local gen=$1
 187     nix-env -p "$opt_profile" --list-generations \
 188         | grep -E "^\s*${gen}" \
 189         | sed -r 's:^\s*::' \
 190         | sed -r 's:\s*$::'
 191 }
 192
 193 if [ -n "$opt_query" ]; then
 194     print_tag $diffFrom
 195     cat "$versA" \
 196         | sed -r 's:^[^-]+-(.*)$:    \1:'
 197
 198     print_line=1
 199 fi
 200
 201 if [ -n "$opt_log" ]; then
 202     gens=$(for gen in $(list_gens); do
 203                ((diffFrom < gen && gen < diffTo)) && echo $gen
 204            done)
 205     # Force the $diffTo generation to be included in this list, instead of using
 206     # `gen <= diffTo` in the preceding loop, so we encounter an error upon the
 207     # event of its nonexistence.
 208     gens=$(echo "$gens"
 209            echo $diffTo)
 210 else
 211     gens=$diffTo
 212 fi
 213
 214 temp_make
 215 add=$(temp_name)
 216 temp_make
 217 rem=$(temp_name)
 218 temp_make
 219 out=$(temp_name)
 220
 221 for gen in $gens; do
 222
 223     [ -n "$print_line" ] && echo
 224
 225     temp_make
 226     versB=$(temp_name)
 227
 228     dirB="${opt_profile}-${gen}-link"
 229     refs=$(nix-store -q --references "$dirB")
 230     (( $? != 0 )) && exit 1
 231     echo "$refs" \
 232         | grep -v env-manifest.nix \
 233         | sort \
 234               > "$versB"
 235
 236     in=$(comm -3 -1 "$versA" "$versB")
 237     sed -r 's:^[^-]*-(.*)$:\1+:' <(echo "$in") \
 238         | sort -f \
 239                > "$add"
 240
 241     un=$(comm -3 -2 "$versA" "$versB")
 242     sed -r 's:^[^-]*-(.*)$:\1-:' <(echo "$un") \
 243         | sort -f \
 244                > "$rem"
 245
 246     cat "$rem" "$add" \
 247         | sort -f \
 248         | sed -r 's:(.*)-$:- \1:' \
 249         | sed -r 's:(.*)\+$:\+ \1:' \
 250         | grep -v '^$' \
 251               > "$out"
 252
 253     if [ -n "$opt_query" -o -n "$opt_log" ]; then
 254
 255         lines=$(wc -l "$out" | cut -d' ' -f1)
 256         tag=$(print_tag "$gen")
 257         (( $? != 0 )) && exit 1
 258         if [ $lines -eq 0 ]; then
 259             echo "$tag   (no change)"
 260         else
 261             echo "$tag"
 262         fi
 263         cat "$out" \
 264             | sed 's:^:    :'
 265
 266         print_line=1
 267
 268     else
 269         echo "diffing from generation $diffFrom to $diffTo"
 270         cat "$out"
 271     fi
 272
 273     versA=$versB
 274
 275 done
 276
 277 exit 0