summaryrefslogtreecommitdiff
path: root/gitsub.sh
blob: 4df47fd5a85b6b882ee66fbebcfb4e0efb67f7dd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
#! /bin/sh
#
# Copyright (C) 2019 Free Software Foundation, Inc.
# Written by Bruno Haible <bruno@clisp.org>, 2019.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

# Program that manages the subdirectories of a git checkout of a package
# that come from other packages (called "dependency packages").
#
# This program is similar in spirit to 'git submodule', with three
# essential differences:
#
#   1) Its options are easy to remember, and do not require knowledge of
#      'git submodule'.
#
#   2) The developer may choose to work on a different checkout for each
#      dependency package.  This is important when the developer is
#      preparing simultaneous changes to the package and the dependency
#      package, or is using the dependency package in several packages.
#
#      The developer indicates this different checkout by setting the
#      environment variable <SUBDIR>_SRCDIR (e.g. GNULIB_SRCDIR) to point to it.
#
#   3) The package maintainer may choose to use or not use git submodules.
#
#      The advantages of management through a git submodule are:
#        - Changes to the dependency package cannot suddenly break your package.
#          In other words, when there is an incompatible change that will cause
#          a breakage, you can fix things at your pace; you are not forced to
#          cope with such breakages in an emergency.
#        - When you need to make a change as a response to a change in the
#          dependency package, your co-developers cannot accidentally mix things
#          up (for example, use a combination of your newest change with an
#          older version of the dependency package).
#
#      The advantages of management without a git submodule (just as a plain
#      subdirectory, let's call it a "subcheckout") are:
#        - The simplicity: you are conceptually always using the newest revision
#          of the dependency package.
#        - You don't have to remember to periodially upgrade the dependency.
#          Upgrading the dependency is an implicit operation.

# This program is meant to be copied to the top-level directory of the package,
# together with a configuration file.  The configuration is supposed to be
# named '.gitmodules' and to define:
# * The git submodules, as described in "man 5 gitmodules" or
#   <https://git-scm.com/docs/gitmodules>.  For example:
#
#       [submodule "gnulib"]
#               url = git://git.savannah.gnu.org/gnulib.git
#               path = gnulib
#
#   You don't add this piece of configuration to .gitmodules manually.  Instead,
#   you would invoke
#     $ git submodule add --name "gnulib" -- git://git.savannah.gnu.org/gnulib.git gnulib
#
# * The subdirectories that are not git submodules, in a similar syntax.  For
#   example:
#
#       [subcheckout "gnulib"]
#               url = git://git.savannah.gnu.org/gnulib.git
#               path = gnulib
#
# Here the URL is the one used for anonymous checkouts of the dependency
# package. If the developer needs a checkout with write access, they can
# either set the GNULIB_SRCDIR environment variable to point to that checkout
# or modify the gnulib/.git/config file to enter a different URL.

scriptname="$0"
scriptversion='2019-04-01'
nl='
'
IFS=" ""	$nl"

# func_usage
# outputs to stdout the --help usage message.
func_usage ()
{
  echo "\
Usage: gitsub.sh pull [SUBDIR]
       gitsub.sh upgrade [SUBDIR]
       gitsub.sh checkout SUBDIR REVISION

Operations:

gitsub.sh pull [GIT_OPTIONS] [SUBDIR]
        You should perform this operation after 'git clone ...' and after
        every 'git pull'.
        It brings your checkout in sync with what the other developers of
        your package have committed and pushed.
        If an environment variable <SUBDIR>_SRCDIR is set, with a non-empty
        value, nothing is done for this SUBDIR.
        Supported GIT_OPTIONS (for expert git users) are:
          --reference <repository>
          --depth <depth>
          --recursive
        If no SUBDIR is specified, the operation applies to all dependencies.

gitsub.sh upgrade [SUBDIR]
        You should perform this operation periodically, to ensure currency
        of the dependency package revisions that you use.
        This operation pulls and checks out the changes that the developers
        of the dependency package have committed and pushed.
        If an environment variable <SUBDIR>_SRCDIR is set, with a non-empty
        value, nothing is done for this SUBDIR.
        If no SUBDIR is specified, the operation applies to all dependencies.

gitsub.sh checkout SUBDIR REVISION
        Checks out a specific revision for a dependency package.
        If an environment variable <SUBDIR>_SRCDIR is set, with a non-empty
        value, this operation fails.

This script requires the git program in the PATH and an internet connection.
"
}

# func_version
# outputs to stdout the --version message.
func_version ()
{
  year=`echo "$scriptversion" | sed -e 's/^\(....\)-.*/\1/'`
  echo "\
gitsub.sh (GNU gnulib) $scriptversion
Copyright (C) 2019-$year Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
"
  printf "Written by %s.\n" "Bruno Haible"
}

# func_fatal_error message
# outputs to stderr a fatal error message, and terminates the program.
# Input:
# - scriptname               name of this program
func_fatal_error ()
{
  echo "$scriptname: *** $1" 1>&2
  echo "$scriptname: *** Stop." 1>&2
  exit 1
}

# func_warning message
# Outputs to stderr a warning message,
func_warning ()
{
  echo "gitsub.sh: warning: $1" 1>&2
}

# func_note message
# Outputs to stdout a note message,
func_note ()
{
  echo "gitsub.sh: note: $1"
}

# Unset CDPATH.  Otherwise, output from 'cd dir' can surprise callers.
(unset CDPATH) >/dev/null 2>&1 && unset CDPATH

# Command-line option processing.
mode=
while test $# -gt 0; do
  case "$1" in
    --help | --hel | --he | --h )
      func_usage
      exit $? ;;
    --version | --versio | --versi | --vers | --ver | --ve | --v )
      func_version
      exit $? ;;
    -- )
      # Stop option processing
      shift
      break ;;
    -* )
      echo "gitsub.sh: unknown option $1" 1>&2
      echo "Try 'gitsub.sh --help' for more information." 1>&2
      exit 1 ;;
    * )
      break ;;
  esac
done
if test $# = 0; then
  echo "gitsub.sh: missing operation argument" 1>&2
  echo "Try 'gitsub.sh --help' for more information." 1>&2
  exit 1
fi
case "$1" in
  pull | upgrade | checkout )
    mode="$1"
    shift ;;
  *)
    echo "gitsub.sh: unknown operation '$1'" 1>&2
    echo "Try 'gitsub.sh --help' for more information." 1>&2
    exit 1 ;;
esac
if { test $mode = upgrade && test $# -gt 1; } \
   || { test $mode = checkout && test $# -gt 2; }; then
  echo "gitsub.sh: too many arguments in '$mode' mode" 1>&2
  echo "Try 'gitsub.sh --help' for more information." 1>&2
  exit 1
fi
if test $# = 0 && test $mode = checkout; then
  echo "gitsub.sh: too few arguments in '$mode' mode" 1>&2
  echo "Try 'gitsub.sh --help' for more information." 1>&2
  exit 1
fi

# Read the configuration.
# Output:
# - subcheckout_names        space-separated list of subcheckout names
# - submodule_names          space-separated list of submodule names
if test -f .gitmodules; then
  subcheckout_names=`git config --file .gitmodules --get-regexp --name-only 'subcheckout\..*\.url' | sed -e 's/^subcheckout\.//' -e 's/\.url$//' | tr -d '\r' | tr '\n' ' '`
  submodule_names=`git config --file .gitmodules --get-regexp --name-only 'submodule\..*\.url' | sed -e 's/^submodule\.//' -e 's/\.url$//' | tr -d '\r' | tr '\n' ' '`
else
  subcheckout_names=
  submodule_names=
fi

# func_validate SUBDIR
# Verifies that the state on the file system is in sync with the declarations
# in the configuration file.
# Input:
# - subcheckout_names        space-separated list of subcheckout names
# - submodule_names          space-separated list of submodule names
# Output:
# - srcdirvar                Environment that the user can set
# - srcdir                   Value of the environment variable
# - path                     if $srcdir = "": relative path of the subdirectory
# - needs_init               if $srcdir = "" and $path is not yet initialized:
#                            true
# - url                      if $srcdir = "" and $path is not yet initialized:
#                            the repository URL
func_validate ()
{
  srcdirvar=`echo "$1" | LC_ALL=C sed -e 's/[^a-zA-Z0-9]/_/g' | LC_ALL=C tr '[a-z]' '[A-Z]'`"_SRCDIR"
  eval 'srcdir=$'"$srcdirvar"
  path=
  url=
  if test -n "$srcdir"; then
    func_note "Ignoring '$1' because $srcdirvar is set."
  else
    found=false
    needs_init=
    case " $subcheckout_names " in *" $1 "*)
      found=true
      # It ought to be a subcheckout.
      path=`git config --file .gitmodules "subcheckout.$1.path"`
      if test -z "$path"; then
        path="$1"
      fi
      if test -d "$path"; then
        if test -d "$path/.git"; then
          # It's a plain checkout.
          :
        else
          if test -f "$path/.git"; then
            # It's a submodule.
            func_fatal_error "Subdirectory '$path' is supposed to be a plain checkout, but it is a submodule."
          else
            func_warning "Ignoring '$path' because it exists but is not a git checkout."
          fi
        fi
      else
        # The subdir does not yet exist.
        needs_init=true
        url=`git config --file .gitmodules "subcheckout.$1.url"`
        if test -z "$url"; then
          func_fatal_error "Property subcheckout.$1.url is not defined in .gitmodules"
        fi
      fi
      ;;
    esac
    case " $submodule_names " in *" $1 "*)
      found=true
      # It ought to be a submodule.
      path=`git config --file .gitmodules "submodule.$1.path"`
      if test -z "$path"; then
        path="$1"
      fi
      if test -d "$path"; then
        if test -d "$path/.git" || test -f "$path/.git"; then
          # It's likely a submodule.
          :
        else
          path_if_empty=`find "$path" -prune -empty 2>/dev/null`
          if test -n "$path_if_empty"; then
            # The subdir is empty.
            needs_init=true
          else
            # The subdir is not empty.
            # It is important to report an error, because we don't want to erase
            # the user's files and 'git submodule update gnulib' sometimes reports
            # "fatal: destination path '$path' already exists and is not an empty directory."
            # but sometimes does not.
            func_fatal_error "Subdir '$path' exists but is not a git checkout."
          fi
        fi
      else
        # The subdir does not yet exist.
        needs_init=true
      fi
      # Another way to determine needs_init could be:
      # if git submodule status "$path" | grep '^-' > /dev/null; then
      #   needs_init=true
      # fi
      if test -n "$needs_init"; then
        url=`git config --file .gitmodules "submodule.$1.url"`
        if test -z "$url"; then
          func_fatal_error "Property submodule.$1.url is not defined in .gitmodules"
        fi
      fi
      ;;
    esac
    if ! $found; then
      func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
    fi
  fi
}

# func_cleanup_current_git_clone
# Cleans up the current 'git clone' operation.
# Input:
# - path
func_cleanup_current_git_clone ()
{
  rm -rf "$path"
  func_fatal_error "git clone failed"
}

# func_pull SUBDIR GIT_OPTIONS
# Implements the 'pull' operation.
func_pull ()
{
  func_validate "$1"
  if test -z "$srcdir"; then
    case " $subcheckout_names " in *" $1 "*)
      # It's a subcheckout.
      if test -d "$path"; then
        if test -d "$path/.git"; then
          (cd "$path" && git pull) || func_fatal_error "git operation failed"
        fi
      else
        # The subdir does not yet exist. Create a plain checkout.
        trap func_cleanup_current_git_clone 1 2 13 15
        git clone $2 "$url" "$path" || func_cleanup_current_git_clone
        trap - 1 2 13 15
      fi
      ;;
    esac
    case " $submodule_names " in *" $1 "*)
      # It's a submodule.
      if test -n "$needs_init"; then
        # Create a submodule checkout.
        git submodule init -- "$path" && git submodule update $2 -- "$path" || func_fatal_error "git operation failed"
      else
        # See https://stackoverflow.com/questions/1030169/easy-way-to-pull-latest-of-all-git-submodules
        # https://stackoverflow.com/questions/4611512/is-there-a-way-to-make-git-pull-automatically-update-submodules
        git submodule update "$path" || func_fatal_error "git operation failed"
      fi
      ;;
    esac
  fi
}

# func_upgrade SUBDIR
# Implements the 'upgrade' operation.
func_upgrade ()
{
  func_validate "$1"
  if test -z "$srcdir"; then
    if test -d "$path"; then
      case " $subcheckout_names " in *" $1 "*)
        # It's a subcheckout.
        if test -d "$path/.git"; then
          (cd "$path" && git pull) || func_fatal_error "git operation failed"
        fi
        ;;
      esac
      case " $submodule_names " in *" $1 "*)
        # It's a submodule.
        if test -z "$needs_init"; then
          (cd "$path" && git fetch && git merge origin/master) || func_fatal_error "git operation failed"
        fi
        ;;
      esac
    else
      # The subdir does not yet exist.
      func_fatal_error "Subdirectory '$path' does not exist yet. Use 'gitsub.sh pull' to create it."
    fi
  fi
}

# func_checkout SUBDIR REVISION
# Implements the 'checkout' operation.
func_checkout ()
{
  func_validate "$1"
  if test -z "$srcdir"; then
    if test -d "$path"; then
      case " $subcheckout_names " in *" $1 "*)
        # It's a subcheckout.
        if test -d "$path/.git"; then
          (cd "$path" && git checkout "$2") || func_fatal_error "git operation failed"
        fi
        ;;
      esac
      case " $submodule_names " in *" $1 "*)
        # It's a submodule.
        if test -z "$needs_init"; then
          (cd "$path" && git checkout "$2") || func_fatal_error "git operation failed"
        fi
        ;;
      esac
    else
      # The subdir does not yet exist.
      func_fatal_error "Subdirectory '$path' does not exist yet. Use 'gitsub.sh pull' to create it."
    fi
  fi
}

case "$mode" in
  pull )
    git_options=""
    while test $# -gt 0; do
      case "$1" in
        --reference=* | --depth=* | --recursive)
          git_options="$git_options $1"
          shift
          ;;
        --reference | --depth)
          git_options="$git_options $1 $2"
          shift; shift
          ;;
        *)
          break
          ;;
      esac
    done
    if test $# -gt 1; then
      echo "gitsub.sh: too many arguments in '$mode' mode" 1>&2
      echo "Try 'gitsub.sh --help' for more information." 1>&2
      exit 1
    fi
    if test $# = 0; then
      for sub in $subcheckout_names $submodule_names; do
        func_pull "$sub" "$git_options"
      done
    else
      valid=false
      for sub in $subcheckout_names $submodule_names; do
        if test "$sub" = "$1"; then
          valid=true
        fi
      done
      if $valid; then
        func_pull "$1" "$git_options"
      else
        func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
      fi
    fi
    ;;

  upgrade )
    if test $# = 0; then
      for sub in $subcheckout_names $submodule_names; do
        func_upgrade "$sub"
      done
    else
      valid=false
      for sub in $subcheckout_names $submodule_names; do
        if test "$sub" = "$1"; then
          valid=true
        fi
      done
      if $valid; then
        func_upgrade "$1"
      else
        func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
      fi
    fi
    ;;

  checkout )
    valid=false
    for sub in $subcheckout_names $submodule_names; do
      if test "$sub" = "$1"; then
        valid=true
      fi
    done
    if $valid; then
      func_checkout "$1" "$2"
    else
      func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
    fi
    ;;
esac