Andrew's git - gitweb.git/blob - contrib/hooks/post-receive-email

   1#!/bin/sh
   2#
   3# Copyright (c) 2007 Andy Parkins
   4#
   5# An example hook script to mail out commit update information.  This hook
   6# sends emails listing new revisions to the repository introduced by the
   7# change being reported.  The rule is that (for branch updates) each commit
   8# will appear on one email and one email only.
   9#
  10# This hook is stored in the contrib/hooks directory.  Your distribution
  11# will have put this somewhere standard.  You should make this script
  12# executable then link to it in the repository you would like to use it in.
  13# For example, on debian the hook is stored in
  14# /usr/share/git-core/contrib/hooks/post-receive-email:
  15#
  16#  chmod a+x post-receive-email
  17#  cd /path/to/your/repository.git
  18#  ln -sf /usr/share/git-core/contrib/hooks/post-receive-email hooks/post-receive
  19#
  20# This hook script assumes it is enabled on the central repository of a
  21# project, with all users pushing only to it and not between each other.  It
  22# will still work if you don't operate in that style, but it would become
  23# possible for the email to be from someone other than the person doing the
  24# push.
  25#
  26# To help with debugging and use on pre-v1.5.1 git servers, this script will
  27# also obey the interface of hooks/update, taking its arguments on the
  28# command line.  Unfortunately, hooks/update is called once for each ref.
  29# To avoid firing one email per ref, this script just prints its output to
  30# the screen when used in this mode.  The output can then be redirected if
  31# wanted.
  32#
  33# Config
  34# ------
  35# hooks.mailinglist
  36#   This is the list that all pushes will go to; leave it blank to not send
  37#   emails for every ref update.
  38# hooks.announcelist
  39#   This is the list that all pushes of annotated tags will go to.  Leave it
  40#   blank to default to the mailinglist field.  The announce emails lists
  41#   the short log summary of the changes since the last annotated tag.
  42# hooks.envelopesender
  43#   If set then the -f option is passed to sendmail to allow the envelope
  44#   sender address to be set
  45# hooks.emailprefix
  46#   All emails have their subjects prefixed with this prefix, or "[SCM]"
  47#   if emailprefix is unset, to aid filtering
  48# hooks.showrev
  49#   The shell command used to format each revision in the email, with
  50#   "%s" replaced with the commit id.  Defaults to "git rev-list -1
  51#   --pretty %s", displaying the commit id, author, date and log
  52#   message.  To list full patches separated by a blank line, you
  53#   could set this to "git show -C %s; echo".
  54#   To list a gitweb/cgit URL *and* a full patch for each change set, use this:
  55#     "t=%s; printf 'http://.../?id=%%s' \$t; echo;echo; git show -C \$t; echo"
  56#   Be careful if "..." contains things that will be expanded by shell "eval"
  57#   or printf.
  58# hooks.emailmaxlines
  59#   The maximum number of lines that should be included in the generated
  60#   email body. If not specified, there is no limit.
  61#   Lines beyond the limit are suppressed and counted, and a final
  62#   line is added indicating the number of suppressed lines.
  63# hooks.diffopts
  64#   Alternate options for the git diff-tree invocation that shows changes.
  65#   Default is "--stat --summary --find-copies-harder". Add -p to those
  66#   options to include a unified diff of changes in addition to the usual
  67#   summary output.
  68#
  69# Notes
  70# -----
  71# All emails include the headers "X-Git-Refname", "X-Git-Oldrev",
  72# "X-Git-Newrev", and "X-Git-Reftype" to enable fine tuned filtering and
  73# give information for debugging.
  74#
  75
  76# ---------------------------- Functions
  77
  78#
  79# Function to prepare for email generation. This decides what type
  80# of update this is and whether an email should even be generated.
  81#
  82prep_for_email()
  83{
  84        # --- Arguments
  85        oldrev=$(git rev-parse $1)
  86        newrev=$(git rev-parse $2)
  87        refname="$3"
  88
  89        # --- Interpret
  90        # 0000->1234 (create)
  91        # 1234->2345 (update)
  92        # 2345->0000 (delete)
  93        if expr "$oldrev" : '0*$' >/dev/null
  94        then
  95                change_type="create"
  96        else
  97                if expr "$newrev" : '0*$' >/dev/null
  98                then
  99                        change_type="delete"
 100                else
 101                        change_type="update"
 102                fi
 103        fi
 104
 105        # --- Get the revision types
 106        newrev_type=$(git cat-file -t $newrev 2> /dev/null)
 107        oldrev_type=$(git cat-file -t "$oldrev" 2> /dev/null)
 108        case "$change_type" in
 109        create|update)
 110                rev="$newrev"
 111                rev_type="$newrev_type"
 112                ;;
 113        delete)
 114                rev="$oldrev"
 115                rev_type="$oldrev_type"
 116                ;;
 117        esac
 118
 119        # The revision type tells us what type the commit is, combined with
 120        # the location of the ref we can decide between
 121        #  - working branch
 122        #  - tracking branch
 123        #  - unannoted tag
 124        #  - annotated tag
 125        case "$refname","$rev_type" in
 126                refs/tags/*,commit)
 127                        # un-annotated tag
 128                        refname_type="tag"
 129                        short_refname=${refname##refs/tags/}
 130                        ;;
 131                refs/tags/*,tag)
 132                        # annotated tag
 133                        refname_type="annotated tag"
 134                        short_refname=${refname##refs/tags/}
 135                        # change recipients
 136                        if [ -n "$announcerecipients" ]; then
 137                                recipients="$announcerecipients"
 138                        fi
 139                        ;;
 140                refs/heads/*,commit)
 141                        # branch
 142                        refname_type="branch"
 143                        short_refname=${refname##refs/heads/}
 144                        ;;
 145                refs/remotes/*,commit)
 146                        # tracking branch
 147                        refname_type="tracking branch"
 148                        short_refname=${refname##refs/remotes/}
 149                        echo >&2 "*** Push-update of tracking branch, $refname"
 150                        echo >&2 "***  - no email generated."
 151                        return 1
 152                        ;;
 153                *)
 154                        # Anything else (is there anything else?)
 155                        echo >&2 "*** Unknown type of update to $refname ($rev_type)"
 156                        echo >&2 "***  - no email generated"
 157                        return 1
 158                        ;;
 159        esac
 160
 161        # Check if we've got anyone to send to
 162        if [ -z "$recipients" ]; then
 163                case "$refname_type" in
 164                        "annotated tag")
 165                                config_name="hooks.announcelist"
 166                                ;;
 167                        *)
 168                                config_name="hooks.mailinglist"
 169                                ;;
 170                esac
 171                echo >&2 "*** $config_name is not set so no email will be sent"
 172                echo >&2 "*** for $refname update $oldrev->$newrev"
 173                return 1
 174        fi
 175
 176        return 0
 177}
 178
 179#
 180# Top level email generation function.  This calls the appropriate
 181# body-generation routine after outputting the common header.
 182#
 183# Note this function doesn't actually generate any email output, that is
 184# taken care of by the functions it calls:
 185#  - generate_email_header
 186#  - generate_create_XXXX_email
 187#  - generate_update_XXXX_email
 188#  - generate_delete_XXXX_email
 189#  - generate_email_footer
 190#
 191# Note also that this function cannot 'exit' from the script; when this
 192# function is running (in hook script mode), the send_mail() function
 193# is already executing in another process, connected via a pipe, and
 194# if this function exits without, whatever has been generated to that
 195# point will be sent as an email... even if nothing has been generated.
 196#
 197generate_email()
 198{
 199        # Email parameters
 200        # The email subject will contain the best description of the ref
 201        # that we can build from the parameters
 202        describe=$(git describe $rev 2>/dev/null)
 203        if [ -z "$describe" ]; then
 204                describe=$rev
 205        fi
 206
 207        generate_email_header
 208
 209        # Call the correct body generation function
 210        fn_name=general
 211        case "$refname_type" in
 212        "tracking branch"|branch)
 213                fn_name=branch
 214                ;;
 215        "annotated tag")
 216                fn_name=atag
 217                ;;
 218        esac
 219
 220        if [ -z "$maxlines" ]; then
 221                generate_${change_type}_${fn_name}_email
 222        else
 223                generate_${change_type}_${fn_name}_email | limit_lines $maxlines
 224        fi
 225
 226        generate_email_footer
 227}
 228
 229generate_email_header()
 230{
 231        # --- Email (all stdout will be the email)
 232        # Generate header
 233        cat <<-EOF
 234        To: $recipients
 235        Subject: ${emailprefix}$projectdesc $refname_type $short_refname ${change_type}d. $describe
 236        X-Git-Refname: $refname
 237        X-Git-Reftype: $refname_type
 238        X-Git-Oldrev: $oldrev
 239        X-Git-Newrev: $newrev
 240
 241        This is an automated email from the git hooks/post-receive script. It was
 242        generated because a ref change was pushed to the repository containing
 243        the project "$projectdesc".
 244
 245        The $refname_type, $short_refname has been ${change_type}d
 246        EOF
 247}
 248
 249generate_email_footer()
 250{
 251        SPACE=" "
 252        cat <<-EOF
 253
 254
 255        hooks/post-receive
 256        --${SPACE}
 257        $projectdesc
 258        EOF
 259}
 260
 261# --------------- Branches
 262
 263#
 264# Called for the creation of a branch
 265#
 266generate_create_branch_email()
 267{
 268        # This is a new branch and so oldrev is not valid
 269        echo "        at  $newrev ($newrev_type)"
 270        echo ""
 271
 272        echo $LOGBEGIN
 273        show_new_revisions
 274        echo $LOGEND
 275}
 276
 277#
 278# Called for the change of a pre-existing branch
 279#
 280generate_update_branch_email()
 281{
 282        # Consider this:
 283        #   1 --- 2 --- O --- X --- 3 --- 4 --- N
 284        #
 285        # O is $oldrev for $refname
 286        # N is $newrev for $refname
 287        # X is a revision pointed to by some other ref, for which we may
 288        #   assume that an email has already been generated.
 289        # In this case we want to issue an email containing only revisions
 290        # 3, 4, and N.  Given (almost) by
 291        #
 292        #  git rev-list N ^O --not --all
 293        #
 294        # The reason for the "almost", is that the "--not --all" will take
 295        # precedence over the "N", and effectively will translate to
 296        #
 297        #  git rev-list N ^O ^X ^N
 298        #
 299        # So, we need to build up the list more carefully.  git rev-parse
 300        # will generate a list of revs that may be fed into git rev-list.
 301        # We can get it to make the "--not --all" part and then filter out
 302        # the "^N" with:
 303        #
 304        #  git rev-parse --not --all | grep -v N
 305        #
 306        # Then, using the --stdin switch to git rev-list we have effectively
 307        # manufactured
 308        #
 309        #  git rev-list N ^O ^X
 310        #
 311        # This leaves a problem when someone else updates the repository
 312        # while this script is running.  Their new value of the ref we're
 313        # working on would be included in the "--not --all" output; and as
 314        # our $newrev would be an ancestor of that commit, it would exclude
 315        # all of our commits.  What we really want is to exclude the current
 316        # value of $refname from the --not list, rather than N itself.  So:
 317        #
 318        #  git rev-parse --not --all | grep -v $(git rev-parse $refname)
 319        #
 320        # Get's us to something pretty safe (apart from the small time
 321        # between refname being read, and git rev-parse running - for that,
 322        # I give up)
 323        #
 324        #
 325        # Next problem, consider this:
 326        #   * --- B --- * --- O ($oldrev)
 327        #          \
 328        #           * --- X --- * --- N ($newrev)
 329        #
 330        # That is to say, there is no guarantee that oldrev is a strict
 331        # subset of newrev (it would have required a --force, but that's
 332        # allowed).  So, we can't simply say rev-list $oldrev..$newrev.
 333        # Instead we find the common base of the two revs and list from
 334        # there.
 335        #
 336        # As above, we need to take into account the presence of X; if
 337        # another branch is already in the repository and points at some of
 338        # the revisions that we are about to output - we don't want them.
 339        # The solution is as before: git rev-parse output filtered.
 340        #
 341        # Finally, tags: 1 --- 2 --- O --- T --- 3 --- 4 --- N
 342        #
 343        # Tags pushed into the repository generate nice shortlog emails that
 344        # summarise the commits between them and the previous tag.  However,
 345        # those emails don't include the full commit messages that we output
 346        # for a branch update.  Therefore we still want to output revisions
 347        # that have been output on a tag email.
 348        #
 349        # Luckily, git rev-parse includes just the tool.  Instead of using
 350        # "--all" we use "--branches"; this has the added benefit that
 351        # "remotes/" will be ignored as well.
 352
 353        # List all of the revisions that were removed by this update, in a
 354        # fast-forward update, this list will be empty, because rev-list O
 355        # ^N is empty.  For a non-fast-forward, O ^N is the list of removed
 356        # revisions
 357        fast_forward=""
 358        rev=""
 359        for rev in $(git rev-list $newrev..$oldrev)
 360        do
 361                revtype=$(git cat-file -t "$rev")
 362                echo "  discards  $rev ($revtype)"
 363        done
 364        if [ -z "$rev" ]; then
 365                fast_forward=1
 366        fi
 367
 368        # List all the revisions from baserev to newrev in a kind of
 369        # "table-of-contents"; note this list can include revisions that
 370        # have already had notification emails and is present to show the
 371        # full detail of the change from rolling back the old revision to
 372        # the base revision and then forward to the new revision
 373        for rev in $(git rev-list $oldrev..$newrev)
 374        do
 375                revtype=$(git cat-file -t "$rev")
 376                echo "       via  $rev ($revtype)"
 377        done
 378
 379        if [ "$fast_forward" ]; then
 380                echo "      from  $oldrev ($oldrev_type)"
 381        else
 382                #  1. Existing revisions were removed.  In this case newrev
 383                #     is a subset of oldrev - this is the reverse of a
 384                #     fast-forward, a rewind
 385                #  2. New revisions were added on top of an old revision,
 386                #     this is a rewind and addition.
 387
 388                # (1) certainly happened, (2) possibly.  When (2) hasn't
 389                # happened, we set a flag to indicate that no log printout
 390                # is required.
 391
 392                echo ""
 393
 394                # Find the common ancestor of the old and new revisions and
 395                # compare it with newrev
 396                baserev=$(git merge-base $oldrev $newrev)
 397                rewind_only=""
 398                if [ "$baserev" = "$newrev" ]; then
 399                        echo "This update discarded existing revisions and left the branch pointing at"
 400                        echo "a previous point in the repository history."
 401                        echo ""
 402                        echo " * -- * -- N ($newrev)"
 403                        echo "            \\"
 404                        echo "             O -- O -- O ($oldrev)"
 405                        echo ""
 406                        echo "The removed revisions are not necessarily gone - if another reference"
 407                        echo "still refers to them they will stay in the repository."
 408                        rewind_only=1
 409                else
 410                        echo "This update added new revisions after undoing existing revisions.  That is"
 411                        echo "to say, the old revision is not a strict subset of the new revision.  This"
 412                        echo "situation occurs when you --force push a change and generate a repository"
 413                        echo "containing something like this:"
 414                        echo ""
 415                        echo " * -- * -- B -- O -- O -- O ($oldrev)"
 416                        echo "            \\"
 417                        echo "             N -- N -- N ($newrev)"
 418                        echo ""
 419                        echo "When this happens we assume that you've already had alert emails for all"
 420                        echo "of the O revisions, and so we here report only the revisions in the N"
 421                        echo "branch from the common base, B."
 422                fi
 423        fi
 424
 425        echo ""
 426        if [ -z "$rewind_only" ]; then
 427                echo "Those revisions listed above that are new to this repository have"
 428                echo "not appeared on any other notification email; so we list those"
 429                echo "revisions in full, below."
 430
 431                echo ""
 432                echo $LOGBEGIN
 433                show_new_revisions
 434
 435                # XXX: Need a way of detecting whether git rev-list actually
 436                # outputted anything, so that we can issue a "no new
 437                # revisions added by this update" message
 438
 439                echo $LOGEND
 440        else
 441                echo "No new revisions were added by this update."
 442        fi
 443
 444        # The diffstat is shown from the old revision to the new revision.
 445        # This is to show the truth of what happened in this change.
 446        # There's no point showing the stat from the base to the new
 447        # revision because the base is effectively a random revision at this
 448        # point - the user will be interested in what this revision changed
 449        # - including the undoing of previous revisions in the case of
 450        # non-fast-forward updates.
 451        echo ""
 452        echo "Summary of changes:"
 453        git diff-tree $diffopts $oldrev..$newrev
 454}
 455
 456#
 457# Called for the deletion of a branch
 458#
 459generate_delete_branch_email()
 460{
 461        echo "       was  $oldrev"
 462        echo ""
 463        echo $LOGBEGIN
 464        git show -s --pretty=oneline $oldrev
 465        echo $LOGEND
 466}
 467
 468# --------------- Annotated tags
 469
 470#
 471# Called for the creation of an annotated tag
 472#
 473generate_create_atag_email()
 474{
 475        echo "        at  $newrev ($newrev_type)"
 476
 477        generate_atag_email
 478}
 479
 480#
 481# Called for the update of an annotated tag (this is probably a rare event
 482# and may not even be allowed)
 483#
 484generate_update_atag_email()
 485{
 486        echo "        to  $newrev ($newrev_type)"
 487        echo "      from  $oldrev (which is now obsolete)"
 488
 489        generate_atag_email
 490}
 491
 492#
 493# Called when an annotated tag is created or changed
 494#
 495generate_atag_email()
 496{
 497        # Use git for-each-ref to pull out the individual fields from the
 498        # tag
 499        eval $(git for-each-ref --shell --format='
 500        tagobject=%(*objectname)
 501        tagtype=%(*objecttype)
 502        tagger=%(taggername)
 503        tagged=%(taggerdate)' $refname
 504        )
 505
 506        echo "   tagging  $tagobject ($tagtype)"
 507        case "$tagtype" in
 508        commit)
 509
 510                # If the tagged object is a commit, then we assume this is a
 511                # release, and so we calculate which tag this tag is
 512                # replacing
 513                prevtag=$(git describe --abbrev=0 $newrev^ 2>/dev/null)
 514
 515                if [ -n "$prevtag" ]; then
 516                        echo "  replaces  $prevtag"
 517                fi
 518                ;;
 519        *)
 520                echo "    length  $(git cat-file -s $tagobject) bytes"
 521                ;;
 522        esac
 523        echo " tagged by  $tagger"
 524        echo "        on  $tagged"
 525
 526        echo ""
 527        echo $LOGBEGIN
 528
 529        # Show the content of the tag message; this might contain a change
 530        # log or release notes so is worth displaying.
 531        git cat-file tag $newrev | sed -e '1,/^$/d'
 532
 533        echo ""
 534        case "$tagtype" in
 535        commit)
 536                # Only commit tags make sense to have rev-list operations
 537                # performed on them
 538                if [ -n "$prevtag" ]; then
 539                        # Show changes since the previous release
 540                        git rev-list --pretty=short "$prevtag..$newrev" | git shortlog
 541                else
 542                        # No previous tag, show all the changes since time
 543                        # began
 544                        git rev-list --pretty=short $newrev | git shortlog
 545                fi
 546                ;;
 547        *)
 548                # XXX: Is there anything useful we can do for non-commit
 549                # objects?
 550                ;;
 551        esac
 552
 553        echo $LOGEND
 554}
 555
 556#
 557# Called for the deletion of an annotated tag
 558#
 559generate_delete_atag_email()
 560{
 561        echo "       was  $oldrev"
 562        echo ""
 563        echo $LOGBEGIN
 564        git show -s --pretty=oneline $oldrev
 565        echo $LOGEND
 566}
 567
 568# --------------- General references
 569
 570#
 571# Called when any other type of reference is created (most likely a
 572# non-annotated tag)
 573#
 574generate_create_general_email()
 575{
 576        echo "        at  $newrev ($newrev_type)"
 577
 578        generate_general_email
 579}
 580
 581#
 582# Called when any other type of reference is updated (most likely a
 583# non-annotated tag)
 584#
 585generate_update_general_email()
 586{
 587        echo "        to  $newrev ($newrev_type)"
 588        echo "      from  $oldrev"
 589
 590        generate_general_email
 591}
 592
 593#
 594# Called for creation or update of any other type of reference
 595#
 596generate_general_email()
 597{
 598        # Unannotated tags are more about marking a point than releasing a
 599        # version; therefore we don't do the shortlog summary that we do for
 600        # annotated tags above - we simply show that the point has been
 601        # marked, and print the log message for the marked point for
 602        # reference purposes
 603        #
 604        # Note this section also catches any other reference type (although
 605        # there aren't any) and deals with them in the same way.
 606
 607        echo ""
 608        if [ "$newrev_type" = "commit" ]; then
 609                echo $LOGBEGIN
 610                git show --no-color --root -s --pretty=medium $newrev
 611                echo $LOGEND
 612        else
 613                # What can we do here?  The tag marks an object that is not
 614                # a commit, so there is no log for us to display.  It's
 615                # probably not wise to output git cat-file as it could be a
 616                # binary blob.  We'll just say how big it is
 617                echo "$newrev is a $newrev_type, and is $(git cat-file -s $newrev) bytes long."
 618        fi
 619}
 620
 621#
 622# Called for the deletion of any other type of reference
 623#
 624generate_delete_general_email()
 625{
 626        echo "       was  $oldrev"
 627        echo ""
 628        echo $LOGBEGIN
 629        git show -s --pretty=oneline $oldrev
 630        echo $LOGEND
 631}
 632
 633
 634# --------------- Miscellaneous utilities
 635
 636#
 637# Show new revisions as the user would like to see them in the email.
 638#
 639show_new_revisions()
 640{
 641        # This shows all log entries that are not already covered by
 642        # another ref - i.e. commits that are now accessible from this
 643        # ref that were previously not accessible
 644        # (see generate_update_branch_email for the explanation of this
 645        # command)
 646
 647        # Revision range passed to rev-list differs for new vs. updated
 648        # branches.
 649        if [ "$change_type" = create ]
 650        then
 651                # Show all revisions exclusive to this (new) branch.
 652                revspec=$newrev
 653        else
 654                # Branch update; show revisions not part of $oldrev.
 655                revspec=$oldrev..$newrev
 656        fi
 657
 658        other_branches=$(git for-each-ref --format='%(refname)' refs/heads/ |
 659            grep -F -v $refname)
 660        git rev-parse --not $other_branches |
 661        if [ -z "$custom_showrev" ]
 662        then
 663                git rev-list --pretty --stdin $revspec
 664        else
 665                git rev-list --stdin $revspec |
 666                while read onerev
 667                do
 668                        eval $(printf "$custom_showrev" $onerev)
 669                done
 670        fi
 671}
 672
 673
 674limit_lines()
 675{
 676        lines=0
 677        skipped=0
 678        while IFS="" read -r line; do
 679                lines=$((lines + 1))
 680                if [ $lines -gt $1 ]; then
 681                        skipped=$((skipped + 1))
 682                else
 683                        printf "%s\n" "$line"
 684                fi
 685        done
 686        if [ $skipped -ne 0 ]; then
 687                echo "... $skipped lines suppressed ..."
 688        fi
 689}
 690
 691
 692send_mail()
 693{
 694        if [ -n "$envelopesender" ]; then
 695                /usr/sbin/sendmail -t -f "$envelopesender"
 696        else
 697                /usr/sbin/sendmail -t
 698        fi
 699}
 700
 701# ---------------------------- main()
 702
 703# --- Constants
 704LOGBEGIN="- Log -----------------------------------------------------------------"
 705LOGEND="-----------------------------------------------------------------------"
 706
 707# --- Config
 708# Set GIT_DIR either from the working directory, or from the environment
 709# variable.
 710GIT_DIR=$(git rev-parse --git-dir 2>/dev/null)
 711if [ -z "$GIT_DIR" ]; then
 712        echo >&2 "fatal: post-receive: GIT_DIR not set"
 713        exit 1
 714fi
 715
 716projectdesc=$(sed -ne '1p' "$GIT_DIR/description" 2>/dev/null)
 717# Check if the description is unchanged from it's default, and shorten it to
 718# a more manageable length if it is
 719if expr "$projectdesc" : "Unnamed repository.*$" >/dev/null
 720then
 721        projectdesc="UNNAMED PROJECT"
 722fi
 723
 724recipients=$(git config hooks.mailinglist)
 725announcerecipients=$(git config hooks.announcelist)
 726envelopesender=$(git config hooks.envelopesender)
 727emailprefix=$(git config hooks.emailprefix || echo '[SCM] ')
 728custom_showrev=$(git config hooks.showrev)
 729maxlines=$(git config hooks.emailmaxlines)
 730diffopts=$(git config hooks.diffopts)
 731: ${diffopts:="--stat --summary --find-copies-harder"}
 732
 733# --- Main loop
 734# Allow dual mode: run from the command line just like the update hook, or
 735# if no arguments are given then run as a hook script
 736if [ -n "$1" -a -n "$2" -a -n "$3" ]; then
 737        # Output to the terminal in command line mode - if someone wanted to
 738        # resend an email; they could redirect the output to sendmail
 739        # themselves
 740        prep_for_email $2 $3 $1 && PAGER= generate_email
 741else
 742        while read oldrev newrev refname
 743        do
 744                prep_for_email $oldrev $newrev $refname || continue
 745                generate_email $maxlines | send_mail
 746        done
 747fi