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git/t/test-lib-functions.sh

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# Library of functions shared by all tests scripts, included by
# test-lib.sh.
#
# Copyright (c) 2005 Junio C Hamano
#
# 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 2 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 http://www.gnu.org/licenses/ .
# The semantics of the editor variables are that of invoking
# sh -c "$EDITOR \"$@\"" files ...
#
# If our trash directory contains shell metacharacters, they will be
# interpreted if we just set $EDITOR directly, so do a little dance with
# environment variables to work around this.
#
# In particular, quoting isn't enough, as the path may contain the same quote
# that we're using.
test_set_editor () {
FAKE_EDITOR="$1"
export FAKE_EDITOR
EDITOR='"$FAKE_EDITOR"'
export EDITOR
}
test_set_index_version () {
GIT_INDEX_VERSION="$1"
export GIT_INDEX_VERSION
}
test_decode_color () {
awk '
function name(n) {
if (n == 0) return "RESET";
if (n == 1) return "BOLD";
if (n == 30) return "BLACK";
if (n == 31) return "RED";
if (n == 32) return "GREEN";
if (n == 33) return "YELLOW";
if (n == 34) return "BLUE";
if (n == 35) return "MAGENTA";
if (n == 36) return "CYAN";
if (n == 37) return "WHITE";
if (n == 40) return "BLACK";
if (n == 41) return "BRED";
if (n == 42) return "BGREEN";
if (n == 43) return "BYELLOW";
if (n == 44) return "BBLUE";
if (n == 45) return "BMAGENTA";
if (n == 46) return "BCYAN";
if (n == 47) return "BWHITE";
}
{
while (match($0, /\033\[[0-9;]*m/) != 0) {
printf "%s<", substr($0, 1, RSTART-1);
codes = substr($0, RSTART+2, RLENGTH-3);
if (length(codes) == 0)
printf "%s", name(0)
else {
n = split(codes, ary, ";");
sep = "";
for (i = 1; i <= n; i++) {
printf "%s%s", sep, name(ary[i]);
sep = ";"
}
}
printf ">";
$0 = substr($0, RSTART + RLENGTH, length($0) - RSTART - RLENGTH + 1);
}
print
}
'
}
nul_to_q () {
perl -pe 'y/\000/Q/'
}
q_to_nul () {
perl -pe 'y/Q/\000/'
}
q_to_cr () {
tr Q '\015'
}
q_to_tab () {
tr Q '\011'
}
qz_to_tab_space () {
tr QZ '\011\040'
}
append_cr () {
sed -e 's/$/Q/' | tr Q '\015'
}
remove_cr () {
tr '\015' Q | sed -e 's/Q$//'
}
# In some bourne shell implementations, the "unset" builtin returns
# nonzero status when a variable to be unset was not set in the first
# place.
#
# Use sane_unset when that should not be considered an error.
sane_unset () {
unset "$@"
return 0
}
test_tick () {
if test -z "${test_tick+set}"
then
test_tick=1112911993
else
test_tick=$(($test_tick + 60))
fi
GIT_COMMITTER_DATE="$test_tick -0700"
GIT_AUTHOR_DATE="$test_tick -0700"
export GIT_COMMITTER_DATE GIT_AUTHOR_DATE
}
# Stop execution and start a shell. This is useful for debugging tests and
# only makes sense together with "-v".
#
# Be sure to remove all invocations of this command before submitting.
test_pause () {
if test "$verbose" = t; then
"$SHELL_PATH" <&6 >&3 2>&4
else
error >&5 "test_pause requires --verbose"
fi
}
# Call test_commit with the arguments "<message> [<file> [<contents> [<tag>]]]"
#
# This will commit a file with the given contents and the given commit
# message, and tag the resulting commit with the given tag name.
#
# <file>, <contents>, and <tag> all default to <message>.
test_commit () {
notick= &&
signoff= &&
while test $# != 0
do
case "$1" in
--notick)
notick=yes
;;
--signoff)
signoff="$1"
;;
*)
break
;;
esac
shift
done &&
file=${2:-"$1.t"} &&
echo "${3-$1}" > "$file" &&
git add "$file" &&
if test -z "$notick"
then
test_tick
fi &&
git commit $signoff -m "$1" &&
git tag "${4:-$1}"
}
# Call test_merge with the arguments "<message> <commit>", where <commit>
# can be a tag pointing to the commit-to-merge.
test_merge () {
test_tick &&
git merge -m "$1" "$2" &&
git tag "$1"
}
# This function helps systems where core.filemode=false is set.
# Use it instead of plain 'chmod +x' to set or unset the executable bit
# of a file in the working directory and add it to the index.
test_chmod () {
chmod "$@" &&
git update-index --add "--chmod=$@"
}
# Unset a configuration variable, but don't fail if it doesn't exist.
test_unconfig () {
git config --unset-all "$@"
config_status=$?
case "$config_status" in
5) # ok, nothing to unset
config_status=0
;;
esac
return $config_status
}
# Set git config, automatically unsetting it after the test is over.
test_config () {
test_when_finished "test_unconfig '$1'" &&
git config "$@"
}
test_config_global () {
test_when_finished "test_unconfig --global '$1'" &&
git config --global "$@"
}
write_script () {
{
echo "#!${2-"$SHELL_PATH"}" &&
cat
} >"$1" &&
chmod +x "$1"
}
# Use test_set_prereq to tell that a particular prerequisite is available.
# The prerequisite can later be checked for in two ways:
#
# - Explicitly using test_have_prereq.
#
# - Implicitly by specifying the prerequisite tag in the calls to
# test_expect_{success,failure,code}.
#
# The single parameter is the prerequisite tag (a simple word, in all
# capital letters by convention).
test_set_prereq () {
satisfied_prereq="$satisfied_prereq$1 "
}
satisfied_prereq=" "
test: allow prerequisite to be evaluated lazily The test prerequisite mechanism is a useful way to allow some tests in a test script to be skipped in environments that do not support certain features (e.g. it is pointless to attempt checking how well symbolic links are handled by Git on filesystems that do not support them). It is OK for commonly used prerequisites to be always tested during start-up of a test script by having a codeblock that tests a feature and calls test_set_prereq, but for an uncommon feature, forcing 90% of scripts to pay the same probing overhead for prerequisite they do not care about is wasteful. Introduce a mechanism to probe the prerequiste lazily. Changes are: - test_lazy_prereq () function, which takes the name of the prerequisite it probes and the script to probe for it, is added. This only registers the name of the prerequiste that can be lazily probed and the script to eval (without running). - test_have_prereq() function (which is used by test_expect_success and also can be called directly by test scripts) learns to look at the list of prerequisites that can be lazily probed, and the prerequisites that have already been probed that way. When asked for a prerequiste that can be but haven't been probed, the script registered with an earlier call to test_lazy_prereq is evaluated and the prerequisite is set. - test_run_lazy_prereq_() function is a helper to run the probe script with the same kind of sandbox as regular tests, helped by Jeff King. Update the codeblock to probe and set SYMLINKS prerequisite using the new mechanism as an example. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-07-27 00:50:45 +02:00
lazily_testable_prereq= lazily_tested_prereq=
# Usage: test_lazy_prereq PREREQ 'script'
test_lazy_prereq () {
lazily_testable_prereq="$lazily_testable_prereq$1 "
eval test_prereq_lazily_$1=\$2
}
test_run_lazy_prereq_ () {
script='
mkdir -p "$TRASH_DIRECTORY/prereq-test-dir" &&
(
cd "$TRASH_DIRECTORY/prereq-test-dir" &&'"$2"'
)'
say >&3 "checking prerequisite: $1"
say >&3 "$script"
test_eval_ "$script"
eval_ret=$?
rm -rf "$TRASH_DIRECTORY/prereq-test-dir"
if test "$eval_ret" = 0; then
say >&3 "prerequisite $1 ok"
else
say >&3 "prerequisite $1 not satisfied"
fi
return $eval_ret
}
test_have_prereq () {
# prerequisites can be concatenated with ','
save_IFS=$IFS
IFS=,
set -- $*
IFS=$save_IFS
total_prereq=0
ok_prereq=0
missing_prereq=
for prerequisite
do
case "$prerequisite" in
!*)
negative_prereq=t
prerequisite=${prerequisite#!}
;;
*)
negative_prereq=
esac
test: allow prerequisite to be evaluated lazily The test prerequisite mechanism is a useful way to allow some tests in a test script to be skipped in environments that do not support certain features (e.g. it is pointless to attempt checking how well symbolic links are handled by Git on filesystems that do not support them). It is OK for commonly used prerequisites to be always tested during start-up of a test script by having a codeblock that tests a feature and calls test_set_prereq, but for an uncommon feature, forcing 90% of scripts to pay the same probing overhead for prerequisite they do not care about is wasteful. Introduce a mechanism to probe the prerequiste lazily. Changes are: - test_lazy_prereq () function, which takes the name of the prerequisite it probes and the script to probe for it, is added. This only registers the name of the prerequiste that can be lazily probed and the script to eval (without running). - test_have_prereq() function (which is used by test_expect_success and also can be called directly by test scripts) learns to look at the list of prerequisites that can be lazily probed, and the prerequisites that have already been probed that way. When asked for a prerequiste that can be but haven't been probed, the script registered with an earlier call to test_lazy_prereq is evaluated and the prerequisite is set. - test_run_lazy_prereq_() function is a helper to run the probe script with the same kind of sandbox as regular tests, helped by Jeff King. Update the codeblock to probe and set SYMLINKS prerequisite using the new mechanism as an example. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-07-27 00:50:45 +02:00
case " $lazily_tested_prereq " in
*" $prerequisite "*)
;;
*)
case " $lazily_testable_prereq " in
*" $prerequisite "*)
eval "script=\$test_prereq_lazily_$prerequisite" &&
if test_run_lazy_prereq_ "$prerequisite" "$script"
then
test_set_prereq $prerequisite
fi
lazily_tested_prereq="$lazily_tested_prereq$prerequisite "
esac
;;
esac
total_prereq=$(($total_prereq + 1))
case "$satisfied_prereq" in
*" $prerequisite "*)
satisfied_this_prereq=t
;;
*)
satisfied_this_prereq=
esac
case "$satisfied_this_prereq,$negative_prereq" in
t,|,t)
ok_prereq=$(($ok_prereq + 1))
;;
*)
# Keep a list of missing prerequisites; restore
# the negative marker if necessary.
prerequisite=${negative_prereq:+!}$prerequisite
if test -z "$missing_prereq"
then
missing_prereq=$prerequisite
else
missing_prereq="$prerequisite,$missing_prereq"
fi
esac
done
test $total_prereq = $ok_prereq
}
test_declared_prereq () {
case ",$test_prereq," in
*,$1,*)
return 0
;;
esac
return 1
}
test_expect_failure () {
test_start_
test "$#" = 3 && { test_prereq=$1; shift; } || test_prereq=
test "$#" = 2 ||
error "bug in the test script: not 2 or 3 parameters to test-expect-failure"
export test_prereq
if ! test_skip "$@"
then
say >&3 "checking known breakage: $2"
if test_run_ "$2" expecting_failure
then
test_known_broken_ok_ "$1"
else
test_known_broken_failure_ "$1"
fi
fi
test_finish_
}
test_expect_success () {
test_start_
test "$#" = 3 && { test_prereq=$1; shift; } || test_prereq=
test "$#" = 2 ||
error "bug in the test script: not 2 or 3 parameters to test-expect-success"
export test_prereq
if ! test_skip "$@"
then
say >&3 "expecting success: $2"
if test_run_ "$2"
then
test_ok_ "$1"
else
test_failure_ "$@"
fi
fi
test_finish_
}
# test_external runs external test scripts that provide continuous
# test output about their progress, and succeeds/fails on
# zero/non-zero exit code. It outputs the test output on stdout even
# in non-verbose mode, and announces the external script with "# run
# <n>: ..." before running it. When providing relative paths, keep in
# mind that all scripts run in "trash directory".
# Usage: test_external description command arguments...
# Example: test_external 'Perl API' perl ../path/to/test.pl
test_external () {
test "$#" = 4 && { test_prereq=$1; shift; } || test_prereq=
test "$#" = 3 ||
error >&5 "bug in the test script: not 3 or 4 parameters to test_external"
descr="$1"
shift
export test_prereq
if ! test_skip "$descr" "$@"
then
# Announce the script to reduce confusion about the
# test output that follows.
say_color "" "# run $test_count: $descr ($*)"
# Export TEST_DIRECTORY, TRASH_DIRECTORY and GIT_TEST_LONG
# to be able to use them in script
export TEST_DIRECTORY TRASH_DIRECTORY GIT_TEST_LONG
# Run command; redirect its stderr to &4 as in
# test_run_, but keep its stdout on our stdout even in
# non-verbose mode.
"$@" 2>&4
if [ "$?" = 0 ]
then
if test $test_external_has_tap -eq 0; then
test_ok_ "$descr"
else
say_color "" "# test_external test $descr was ok"
test_success=$(($test_success + 1))
fi
else
if test $test_external_has_tap -eq 0; then
test_failure_ "$descr" "$@"
else
say_color error "# test_external test $descr failed: $@"
test_failure=$(($test_failure + 1))
fi
fi
fi
}
# Like test_external, but in addition tests that the command generated
# no output on stderr.
test_external_without_stderr () {
# The temporary file has no (and must have no) security
# implications.
tmp=${TMPDIR:-/tmp}
stderr="$tmp/git-external-stderr.$$.tmp"
test_external "$@" 4> "$stderr"
[ -f "$stderr" ] || error "Internal error: $stderr disappeared."
descr="no stderr: $1"
shift
say >&3 "# expecting no stderr from previous command"
if [ ! -s "$stderr" ]; then
rm "$stderr"
if test $test_external_has_tap -eq 0; then
test_ok_ "$descr"
else
say_color "" "# test_external_without_stderr test $descr was ok"
test_success=$(($test_success + 1))
fi
else
if [ "$verbose" = t ]; then
output=`echo; echo "# Stderr is:"; cat "$stderr"`
else
output=
fi
# rm first in case test_failure exits.
rm "$stderr"
if test $test_external_has_tap -eq 0; then
test_failure_ "$descr" "$@" "$output"
else
say_color error "# test_external_without_stderr test $descr failed: $@: $output"
test_failure=$(($test_failure + 1))
fi
fi
}
# debugging-friendly alternatives to "test [-f|-d|-e]"
# The commands test the existence or non-existence of $1. $2 can be
# given to provide a more precise diagnosis.
test_path_is_file () {
if ! [ -f "$1" ]
then
echo "File $1 doesn't exist. $*"
false
fi
}
test_path_is_dir () {
if ! [ -d "$1" ]
then
echo "Directory $1 doesn't exist. $*"
false
fi
}
test_path_is_missing () {
if [ -e "$1" ]
then
echo "Path exists:"
ls -ld "$1"
if [ $# -ge 1 ]; then
echo "$*"
fi
false
fi
}
# test_line_count checks that a file has the number of lines it
# ought to. For example:
#
# test_expect_success 'produce exactly one line of output' '
# do something >output &&
# test_line_count = 1 output
# '
#
# is like "test $(wc -l <output) = 1" except that it passes the
# output through when the number of lines is wrong.
test_line_count () {
if test $# != 3
then
error "bug in the test script: not 3 parameters to test_line_count"
elif ! test $(wc -l <"$3") "$1" "$2"
then
echo "test_line_count: line count for $3 !$1 $2"
cat "$3"
return 1
fi
}
# This is not among top-level (test_expect_success | test_expect_failure)
# but is a prefix that can be used in the test script, like:
#
# test_expect_success 'complain and die' '
# do something &&
# do something else &&
# test_must_fail git checkout ../outerspace
# '
#
# Writing this as "! git checkout ../outerspace" is wrong, because
# the failure could be due to a segv. We want a controlled failure.
test_must_fail () {
"$@"
exit_code=$?
if test $exit_code = 0; then
echo >&2 "test_must_fail: command succeeded: $*"
return 1
elif test $exit_code -gt 129 -a $exit_code -le 192; then
echo >&2 "test_must_fail: died by signal: $*"
return 1
elif test $exit_code = 127; then
echo >&2 "test_must_fail: command not found: $*"
return 1
elif test $exit_code = 126; then
echo >&2 "test_must_fail: valgrind error: $*"
return 1
fi
return 0
}
# Similar to test_must_fail, but tolerates success, too. This is
# meant to be used in contexts like:
#
# test_expect_success 'some command works without configuration' '
# test_might_fail git config --unset all.configuration &&
# do something
# '
#
# Writing "git config --unset all.configuration || :" would be wrong,
# because we want to notice if it fails due to segv.
test_might_fail () {
"$@"
exit_code=$?
if test $exit_code -gt 129 -a $exit_code -le 192; then
echo >&2 "test_might_fail: died by signal: $*"
return 1
elif test $exit_code = 127; then
echo >&2 "test_might_fail: command not found: $*"
return 1
fi
return 0
}
# Similar to test_must_fail and test_might_fail, but check that a
# given command exited with a given exit code. Meant to be used as:
#
# test_expect_success 'Merge with d/f conflicts' '
# test_expect_code 1 git merge "merge msg" B master
# '
test_expect_code () {
want_code=$1
shift
"$@"
exit_code=$?
if test $exit_code = $want_code
then
return 0
fi
echo >&2 "test_expect_code: command exited with $exit_code, we wanted $want_code $*"
return 1
}
# test_cmp is a helper function to compare actual and expected output.
# You can use it like:
#
# test_expect_success 'foo works' '
# echo expected >expected &&
# foo >actual &&
# test_cmp expected actual
# '
#
# This could be written as either "cmp" or "diff -u", but:
# - cmp's output is not nearly as easy to read as diff -u
# - not all diff versions understand "-u"
test_cmp() {
$GIT_TEST_CMP "$@"
}
# test_cmp_bin - helper to compare binary files
test_cmp_bin() {
cmp "$@"
}
# Check if the file expected to be empty is indeed empty, and barfs
# otherwise.
test_must_be_empty () {
if test -s "$1"
then
echo "'$1' is not empty, it contains:"
cat "$1"
return 1
fi
}
# Tests that its two parameters refer to the same revision
test_cmp_rev () {
git rev-parse --verify "$1" >expect.rev &&
git rev-parse --verify "$2" >actual.rev &&
test_cmp expect.rev actual.rev
}
# Print a sequence of numbers or letters in increasing order. This is
# similar to GNU seq(1), but the latter might not be available
# everywhere (and does not do letters). It may be used like:
#
# for i in `test_seq 100`; do
# for j in `test_seq 10 20`; do
# for k in `test_seq a z`; do
# echo $i-$j-$k
# done
# done
# done
test_seq () {
case $# in
1) set 1 "$@" ;;
2) ;;
*) error "bug in the test script: not 1 or 2 parameters to test_seq" ;;
esac
perl -le 'print for $ARGV[0]..$ARGV[1]' -- "$@"
}
# This function can be used to schedule some commands to be run
# unconditionally at the end of the test to restore sanity:
#
# test_expect_success 'test core.capslock' '
# git config core.capslock true &&
# test_when_finished "git config --unset core.capslock" &&
# hello world
# '
#
# That would be roughly equivalent to
#
# test_expect_success 'test core.capslock' '
# git config core.capslock true &&
# hello world
# git config --unset core.capslock
# '
#
# except that the greeting and config --unset must both succeed for
# the test to pass.
#
# Note that under --immediate mode, no clean-up is done to help diagnose
# what went wrong.
test_when_finished () {
test_cleanup="{ $*
} && (exit \"\$eval_ret\"); eval_ret=\$?; $test_cleanup"
}
# Most tests can use the created repository, but some may need to create more.
# Usage: test_create_repo <directory>
test_create_repo () {
test "$#" = 1 ||
error "bug in the test script: not 1 parameter to test-create-repo"
repo="$1"
mkdir -p "$repo"
(
cd "$repo" || error "Cannot setup test environment"
"$GIT_EXEC_PATH/git-init" "--template=$GIT_BUILD_DIR/templates/blt/" >&3 2>&4 ||
error "cannot run git init -- have you built things yet?"
mv .git/hooks .git/hooks-disabled
) || exit
}
# This function helps on symlink challenged file systems when it is not
# important that the file system entry is a symbolic link.
# Use test_ln_s_add instead of "ln -s x y && git add y" to add a
# symbolic link entry y to the index.
test_ln_s_add () {
if test_have_prereq SYMLINKS
then
ln -s "$1" "$2" &&
git update-index --add "$2"
else
printf '%s' "$1" >"$2" &&
ln_s_obj=$(git hash-object -w "$2") &&
git update-index --add --cacheinfo 120000 $ln_s_obj "$2"
fi
}
perl () {
command "$PERL_PATH" "$@"
}
tests: turn on network daemon tests by default We do not run the httpd nor git-daemon tests by default, as they are rather heavyweight and require network access (albeit over localhost). However, it would be nice if more pepole ran them, for two reasons: 1. We would get more test coverage on more systems. 2. The point of the test suite is to find regressions. It is very easy to change some of the underlying code and break the httpd code without realizing you are even affecting it. Running the httpd tests helps find these problems sooner (ideally before the patches even hit the list). We still want to leave an "out", though, for people who really do not want to run them. For that reason, the GIT_TEST_HTTPD and GIT_TEST_GIT_DAEMON variables are now tri-state booleans (true/false/auto), so you can say GIT_TEST_HTTPD=false to turn the tests back off. To support those who want a stable single way to disable these tests across versions of Git before and after this change, an empty string explicitly set to these variables is also taken as "false", so the behaviour changes only for those who: a. did not express any preference by leaving these variables unset. They did not test these features before, but now they do; or b. did express that they want to test these features by setting GIT_TEST_FEATURE=false (or any equivalent other ways to tell "false" to Git, e.g. "0"), which has been a valid but funny way to say that they do want to test the feature only because we used to interpret any non-empty string to mean "yes please test". They no longer test that feature. In addition, we are forgiving of common setup failures (e.g., you do not have apache installed, or have an old version) when the tri-state is "auto" (or unset), but report an error when it is "true". This makes "auto" a sane default, as we should not cause failures on setups where the tests cannot run. But it allows people who use "true" to catch regressions in their system (e.g., they uninstalled apache, but were expecting their automated test runs to test git-httpd, and would want to be notified). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-10 22:29:37 +01:00
# Is the value one of the various ways to spell a boolean true/false?
test_normalize_bool () {
git -c magic.variable="$1" config --bool magic.variable 2>/dev/null
}
# Given a variable $1, normalize the value of it to one of "true",
# "false", or "auto" and store the result to it.
#
# test_tristate GIT_TEST_HTTPD
#
# A variable set to an empty string is set to 'false'.
# A variable set to 'false' or 'auto' keeps its value.
# Anything else is set to 'true'.
# An unset variable defaults to 'auto'.
#
# The last rule is to allow people to set the variable to an empty
# string and export it to decline testing the particular feature
# for versions both before and after this change. We used to treat
# both unset and empty variable as a signal for "do not test" and
# took any non-empty string as "please test".
test_tristate () {
if eval "test x\"\${$1+isset}\" = xisset"
then
# explicitly set
eval "
case \"\$$1\" in
'') $1=false ;;
auto) ;;
*) $1=\$(test_normalize_bool \$$1 || echo true) ;;
esac
"
else
eval "$1=auto"
fi
}
# Exit the test suite, either by skipping all remaining tests or by
# exiting with an error. If "$1" is "auto", we then we assume we were
# opportunistically trying to set up some tests and we skip. If it is
# "true", then we report a failure.
#
# The error/skip message should be given by $2.
#
test_skip_or_die () {
case "$1" in
auto)
skip_all=$2
test_done
;;
true)
error "$2"
;;
*)
error "BUG: test tristate is '$1' (real error: $2)"
esac
}
# The following mingw_* functions obey POSIX shell syntax, but are actually
# bash scripts, and are meant to be used only with bash on Windows.
# A test_cmp function that treats LF and CRLF equal and avoids to fork
# diff when possible.
mingw_test_cmp () {
# Read text into shell variables and compare them. If the results
# are different, use regular diff to report the difference.
local test_cmp_a= test_cmp_b=
# When text came from stdin (one argument is '-') we must feed it
# to diff.
local stdin_for_diff=
# Since it is difficult to detect the difference between an
# empty input file and a failure to read the files, we go straight
# to diff if one of the inputs is empty.
if test -s "$1" && test -s "$2"
then
# regular case: both files non-empty
mingw_read_file_strip_cr_ test_cmp_a <"$1"
mingw_read_file_strip_cr_ test_cmp_b <"$2"
elif test -s "$1" && test "$2" = -
then
# read 2nd file from stdin
mingw_read_file_strip_cr_ test_cmp_a <"$1"
mingw_read_file_strip_cr_ test_cmp_b
stdin_for_diff='<<<"$test_cmp_b"'
elif test "$1" = - && test -s "$2"
then
# read 1st file from stdin
mingw_read_file_strip_cr_ test_cmp_a
mingw_read_file_strip_cr_ test_cmp_b <"$2"
stdin_for_diff='<<<"$test_cmp_a"'
fi
test -n "$test_cmp_a" &&
test -n "$test_cmp_b" &&
test "$test_cmp_a" = "$test_cmp_b" ||
eval "diff -u \"\$@\" $stdin_for_diff"
}
# $1 is the name of the shell variable to fill in
mingw_read_file_strip_cr_ () {
# Read line-wise using LF as the line separator
# and use IFS to strip CR.
local line
while :
do
if IFS=$'\r' read -r -d $'\n' line
then
# good
line=$line$'\n'
else
# we get here at EOF, but also if the last line
# was not terminated by LF; in the latter case,
# some text was read
if test -z "$line"
then
# EOF, really
break
fi
fi
eval "$1=\$$1\$line"
done
}