Merge branch 'jn/svn-fe'

* jn/svn-fe: (36 commits)
  vcs-svn: suppress a -Wtype-limits warning
  vcs-svn: allow import of > 4GiB files
  vcs-svn: rename check_overflow arguments for clarity
  vcs-svn/svndiff.c: squelch false "unused" warning from gcc
  vcs-svn: reset first_commit_done in fast_export_init
  vcs-svn: do not initialize report_buffer twice
  vcs-svn: avoid hangs from corrupt deltas
  vcs-svn: guard against overflow when computing preimage length
  vcs-svn: cap number of bytes read from sliding view
  test-svn-fe: split off "test-svn-fe -d" into a separate function
  vcs-svn: implement text-delta handling
  vcs-svn: let deltas use data from preimage
  vcs-svn: let deltas use data from postimage
  vcs-svn: verify that deltas consume all inline data
  vcs-svn: implement copyfrom_data delta instruction
  vcs-svn: read instructions from deltas
  vcs-svn: read inline data from deltas
  vcs-svn: read the preimage when applying deltas
  vcs-svn: parse svndiff0 window header
  vcs-svn: skeleton of an svn delta parser
  ...

3 files changed, 556 insertions, 174 deletions

diff --git a/t/t0080-vcs-svn.sh b/t/t0080-vcs-svn.sh
deleted file mode 100755
index 99a314b080..0000000000
--- a/t/t0080-vcs-svn.sh
+++ /dev/null
@@ -1,117 +0,0 @@
-#!/bin/sh
-
-test_description='check infrastructure for svn importer'
-
-. ./test-lib.sh
-uint32_max=4294967295
-
-test_expect_success 'obj pool: store data' '
-	cat <<-\EOF >expected &&
-	0
-	1
-	EOF
-
-	test-obj-pool <<-\EOF >actual &&
-	alloc one 16
-	set one 13
-	test one 13
-	reset one
-	EOF
-	test_cmp expected actual
-'
-
-test_expect_success 'obj pool: NULL is offset ~0' '
-	echo "$uint32_max" >expected &&
-	echo null one | test-obj-pool >actual &&
-	test_cmp expected actual
-'
-
-test_expect_success 'obj pool: out-of-bounds access' '
-	cat <<-EOF >expected &&
-	0
-	0
-	$uint32_max
-	$uint32_max
-	16
-	20
-	$uint32_max
-	EOF
-
-	test-obj-pool <<-\EOF >actual &&
-	alloc one 16
-	alloc two 16
-	offset one 20
-	offset two 20
-	alloc one 5
-	offset one 20
-	free one 1
-	offset one 20
-	reset one
-	reset two
-	EOF
-	test_cmp expected actual
-'
-
-test_expect_success 'obj pool: high-water mark' '
-	cat <<-\EOF >expected &&
-	0
-	0
-	10
-	20
-	20
-	20
-	EOF
-
-	test-obj-pool <<-\EOF >actual &&
-	alloc one 10
-	committed one
-	alloc one 10
-	commit one
-	committed one
-	alloc one 10
-	free one 20
-	committed one
-	reset one
-	EOF
-	test_cmp expected actual
-'
-
-test_expect_success 'string pool' '
-	echo a does not equal b >expected.differ &&
-	echo a equals a >expected.match &&
-	echo equals equals equals >expected.matchmore &&
-
-	test-string-pool "a,--b" >actual.differ &&
-	test-string-pool "a,a" >actual.match &&
-	test-string-pool "equals-equals" >actual.matchmore &&
-	test_must_fail test-string-pool a,a,a &&
-	test_must_fail test-string-pool a &&
-
-	test_cmp expected.differ actual.differ &&
-	test_cmp expected.match actual.match &&
-	test_cmp expected.matchmore actual.matchmore
-'
-
-test_expect_success 'treap sort' '
-	cat <<-\EOF >unsorted &&
-	68
-	12
-	13
-	13
-	68
-	13
-	13
-	21
-	10
-	11
-	12
-	13
-	13
-	EOF
-	sort unsorted >expected &&
-
-	test-treap <unsorted >actual &&
-	test_cmp expected actual
-'
-
-test_done
diff --git a/t/t9010-svn-fe.sh b/t/t9010-svn-fe.sh
index 6f6175a8f7..b7eed2489f 100755
--- a/t/t9010-svn-fe.sh
+++ b/t/t9010-svn-fe.sh
@@ -5,8 +5,27 @@ test_description='check svn dumpfile importer'
 . ./test-lib.sh
 
 reinit_git () {
+	if ! test_declared_prereq PIPE
+	then
+		echo >&4 "reinit_git: need to declare PIPE prerequisite"
+		return 127
+	fi
 	rm -fr .git &&
-	git init
+	rm -f stream backflow &&
+	git init &&
+	mkfifo stream backflow
+}
+
+try_dump () {
+	input=$1 &&
+	maybe_fail_svnfe=${2:+test_$2} &&
+	maybe_fail_fi=${3:+test_$3} &&
+
+	{
+		$maybe_fail_svnfe test-svn-fe "$input" >stream 3<backflow &
+	} &&
+	$maybe_fail_fi git fast-import --cat-blob-fd=3 <stream 3>backflow &&
+	wait $!
 }
 
 properties () {
@@ -35,21 +54,27 @@ text_no_props () {
 
 >empty
 
-test_expect_success 'empty dump' '
+test_expect_success 'setup: have pipes?' '
+	rm -f frob &&
+	if mkfifo frob
+	then
+		test_set_prereq PIPE
+	fi
+'
+
+test_expect_success PIPE 'empty dump' '
 	reinit_git &&
 	echo "SVN-fs-dump-format-version: 2" >input &&
-	test-svn-fe input >stream &&
-	git fast-import <stream
+	try_dump input
 '
 
-test_expect_success 'v4 dumps not supported' '
+test_expect_success PIPE 'v4 dumps not supported' '
 	reinit_git &&
 	echo "SVN-fs-dump-format-version: 4" >v4.dump &&
-	test_must_fail test-svn-fe v4.dump >stream &&
-	test_cmp empty stream
+	try_dump v4.dump must_fail
 '
 
-test_expect_failure 'empty revision' '
+test_expect_failure PIPE 'empty revision' '
 	reinit_git &&
 	printf "rev <nobody, nobody@local>: %s\n" "" "" >expect &&
 	cat >emptyrev.dump <<-\EOF &&
@@ -64,13 +89,12 @@ test_expect_failure 'empty revision' '
 	Content-length: 0
 
 	EOF
-	test-svn-fe emptyrev.dump >stream &&
-	git fast-import <stream &&
+	try_dump emptyrev.dump &&
 	git log -p --format="rev <%an, %ae>: %s" HEAD >actual &&
 	test_cmp expect actual
 '
 
-test_expect_success 'empty properties' '
+test_expect_success PIPE 'empty properties' '
 	reinit_git &&
 	printf "rev <nobody, nobody@local>: %s\n" "" "" >expect &&
 	cat >emptyprop.dump <<-\EOF &&
@@ -88,13 +112,12 @@ test_expect_success 'empty properties' '
 
 	PROPS-END
 	EOF
-	test-svn-fe emptyprop.dump >stream &&
-	git fast-import <stream &&
+	try_dump emptyprop.dump &&
 	git log -p --format="rev <%an, %ae>: %s" HEAD >actual &&
 	test_cmp expect actual
 '
 
-test_expect_success 'author name and commit message' '
+test_expect_success PIPE 'author name and commit message' '
 	reinit_git &&
 	echo "<author@example.com, author@example.com@local>" >expect.author &&
 	cat >message <<-\EOF &&
@@ -121,15 +144,14 @@ test_expect_success 'author name and commit message' '
 		echo &&
 		cat props
 	} >log.dump &&
-	test-svn-fe log.dump >stream &&
-	git fast-import <stream &&
+	try_dump log.dump &&
 	git log -p --format="%B" HEAD >actual.log &&
 	git log --format="<%an, %ae>" >actual.author &&
 	test_cmp message actual.log &&
 	test_cmp expect.author actual.author
 '
 
-test_expect_success 'unsupported properties are ignored' '
+test_expect_success PIPE 'unsupported properties are ignored' '
 	reinit_git &&
 	echo author >expect &&
 	cat >extraprop.dump <<-\EOF &&
@@ -149,13 +171,12 @@ test_expect_success 'unsupported properties are ignored' '
 	author
 	PROPS-END
 	EOF
-	test-svn-fe extraprop.dump >stream &&
-	git fast-import <stream &&
+	try_dump extraprop.dump &&
 	git log -p --format=%an HEAD >actual &&
 	test_cmp expect actual
 '
 
-test_expect_failure 'timestamp and empty file' '
+test_expect_failure PIPE 'timestamp and empty file' '
 	echo author@example.com >expect.author &&
 	echo 1999-01-01 >expect.date &&
 	echo file >expect.files &&
@@ -186,8 +207,7 @@ test_expect_failure 'timestamp and empty file' '
 
 		EOF
 	} >emptyfile.dump &&
-	test-svn-fe emptyfile.dump >stream &&
-	git fast-import <stream &&
+	try_dump emptyfile.dump &&
 	git log --format=%an HEAD >actual.author &&
 	git log --date=short --format=%ad HEAD >actual.date &&
 	git ls-tree -r --name-only HEAD >actual.files &&
@@ -198,7 +218,7 @@ test_expect_failure 'timestamp and empty file' '
 	test_cmp empty file
 '
 
-test_expect_success 'directory with files' '
+test_expect_success PIPE 'directory with files' '
 	reinit_git &&
 	printf "%s\n" directory/file1 directory/file2 >expect.files &&
 	echo hi >hi &&
@@ -242,8 +262,7 @@ test_expect_success 'directory with files' '
 		EOF
 		text_no_props hi
 	} >directory.dump &&
-	test-svn-fe directory.dump >stream &&
-	git fast-import <stream &&
+	try_dump directory.dump &&
 
 	git ls-tree -r --name-only HEAD >actual.files &&
 	git checkout HEAD directory &&
@@ -252,7 +271,107 @@ test_expect_success 'directory with files' '
 	test_cmp hi directory/file2
 '
 
-test_expect_success 'node without action' '
+test_expect_success PIPE 'branch name with backslash' '
+	reinit_git &&
+	sort <<-\EOF >expect.branch-files &&
+	trunk/file1
+	trunk/file2
+	"branches/UpdateFOPto094\\/file1"
+	"branches/UpdateFOPto094\\/file2"
+	EOF
+
+	echo hi >hi &&
+	echo hello >hello &&
+	{
+		properties \
+			svn:author author@example.com \
+			svn:date "1999-02-02T00:01:02.000000Z" \
+			svn:log "add directory with some files in it" &&
+		echo PROPS-END
+	} >props.setup &&
+	{
+		properties \
+			svn:author brancher@example.com \
+			svn:date "2007-12-06T21:38:34.000000Z" \
+			svn:log "Updating fop to .94 and adjust fo-stylesheets" &&
+		echo PROPS-END
+	} >props.branch &&
+	{
+		cat <<-EOF &&
+		SVN-fs-dump-format-version: 3
+
+		Revision-number: 1
+		EOF
+		echo Prop-content-length: $(wc -c <props.setup) &&
+		echo Content-length: $(wc -c <props.setup) &&
+		echo &&
+		cat props.setup &&
+		cat <<-\EOF &&
+
+		Node-path: trunk
+		Node-kind: dir
+		Node-action: add
+		Prop-content-length: 10
+		Content-length: 10
+
+		PROPS-END
+
+		Node-path: branches
+		Node-kind: dir
+		Node-action: add
+		Prop-content-length: 10
+		Content-length: 10
+
+		PROPS-END
+
+		Node-path: trunk/file1
+		Node-kind: file
+		Node-action: add
+		EOF
+		text_no_props hello &&
+		cat <<-\EOF &&
+		Node-path: trunk/file2
+		Node-kind: file
+		Node-action: add
+		EOF
+		text_no_props hi &&
+		cat <<-\EOF &&
+
+		Revision-number: 2
+		EOF
+		echo Prop-content-length: $(wc -c <props.branch) &&
+		echo Content-length: $(wc -c <props.branch) &&
+		echo &&
+		cat props.branch &&
+		cat <<-\EOF
+
+		Node-path: branches/UpdateFOPto094\
+		Node-kind: dir
+		Node-action: add
+		Node-copyfrom-rev: 1
+		Node-copyfrom-path: trunk
+
+		Node-kind: dir
+		Node-action: add
+		Prop-content-length: 34
+		Content-length: 34
+
+		K 13
+		svn:mergeinfo
+		V 0
+
+		PROPS-END
+		EOF
+	} >branch.dump &&
+	try_dump branch.dump &&
+
+	git ls-tree -r --name-only HEAD |
+	sort >actual.branch-files &&
+	test_cmp expect.branch-files actual.branch-files
+'
+
+test_expect_success PIPE 'node without action' '
+	reinit_git &&
 	cat >inaction.dump <<-\EOF &&
 	SVN-fs-dump-format-version: 3
 
@@ -269,10 +388,11 @@ test_expect_success 'node without action' '
 
 	PROPS-END
 	EOF
-	test_must_fail test-svn-fe inaction.dump
+	try_dump inaction.dump must_fail
 '
 
-test_expect_success 'action: add node without text' '
+test_expect_success PIPE 'action: add node without text' '
+	reinit_git &&
 	cat >textless.dump <<-\EOF &&
 	SVN-fs-dump-format-version: 3
 
@@ -290,10 +410,10 @@ test_expect_success 'action: add node without text' '
 
 	PROPS-END
 	EOF
-	test_must_fail test-svn-fe textless.dump
+	try_dump textless.dump must_fail
 '
 
-test_expect_failure 'change file mode but keep old content' '
+test_expect_failure PIPE 'change file mode but keep old content' '
 	reinit_git &&
 	cat >expect <<-\EOF &&
 	OBJID
@@ -356,8 +476,7 @@ test_expect_failure 'change file mode but keep old content' '
 
 	PROPS-END
 	EOF
-	test-svn-fe filemode.dump >stream &&
-	git fast-import <stream &&
+	try_dump filemode.dump &&
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
@@ -370,7 +489,7 @@ test_expect_failure 'change file mode but keep old content' '
 	test_cmp hello actual.target
 '
 
-test_expect_success 'NUL in property value' '
+test_expect_success PIPE 'NUL in property value' '
 	reinit_git &&
 	echo "commit message" >expect.message &&
 	{
@@ -391,13 +510,12 @@ test_expect_success 'NUL in property value' '
 		echo &&
 		cat props
 	} >nulprop.dump &&
-	test-svn-fe nulprop.dump >stream &&
-	git fast-import <stream &&
+	try_dump nulprop.dump &&
 	git diff-tree --always -s --format=%s HEAD >actual.message &&
 	test_cmp expect.message actual.message
 '
 
-test_expect_success 'NUL in log message, file content, and property name' '
+test_expect_success PIPE 'NUL in log message, file content, and property name' '
 	# Caveat: svnadmin 1.6.16 (r1073529) truncates at \0 in the
 	# svn:specialQnotreally example.
 	reinit_git &&
@@ -458,8 +576,7 @@ test_expect_success 'NUL in log message, file content, and property name' '
 		link hello
 		EOF
 	} >8bitclean.dump &&
-	test-svn-fe 8bitclean.dump >stream &&
-	git fast-import <stream &&
+	try_dump 8bitclean.dump &&
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
@@ -478,7 +595,7 @@ test_expect_success 'NUL in log message, file content, and property name' '
 	test_cmp expect.hello2 actual.hello2
 '
 
-test_expect_success 'change file mode and reiterate content' '
+test_expect_success PIPE 'change file mode and reiterate content' '
 	reinit_git &&
 	cat >expect <<-\EOF &&
 	OBJID
@@ -490,7 +607,7 @@ test_expect_success 'change file mode and reiterate content' '
 	EOF
 	echo "link hello" >expect.blob &&
 	echo hello >hello &&
-	cat >filemode.dump <<-\EOF &&
+	cat >filemode2.dump <<-\EOF &&
 	SVN-fs-dump-format-version: 3
 
 	Revision-number: 1
@@ -545,8 +662,7 @@ test_expect_success 'change file mode and reiterate content' '
 	PROPS-END
 	link hello
 	EOF
-	test-svn-fe filemode.dump >stream &&
-	git fast-import <stream &&
+	try_dump filemode2.dump &&
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
@@ -559,7 +675,8 @@ test_expect_success 'change file mode and reiterate content' '
 	test_cmp hello actual.target
 '
 
-test_expect_success 'deltas not supported' '
+test_expect_success PIPE 'deltas supported' '
+	reinit_git &&
 	{
 		# (old) h + (inline) ello + (old) \n
 		printf "SVNQ%b%b%s" "Q\003\006\005\004" "\001Q\0204\001\002" "ello" |
@@ -619,10 +736,10 @@ test_expect_success 'deltas not supported' '
 		echo PROPS-END &&
 		cat delta
 	} >delta.dump &&
-	test_must_fail test-svn-fe delta.dump
+	try_dump delta.dump
 '
 
-test_expect_success 'property deltas supported' '
+test_expect_success PIPE 'property deltas supported' '
 	reinit_git &&
 	cat >expect <<-\EOF &&
 	OBJID
@@ -678,8 +795,7 @@ test_expect_success 'property deltas supported' '
 		PROPS-END
 		EOF
 	} >propdelta.dump &&
-	test-svn-fe propdelta.dump >stream &&
-	git fast-import <stream &&
+	try_dump propdelta.dump &&
 	{
 		git rev-list HEAD |
 		git diff-tree --stdin |
@@ -688,7 +804,7 @@ test_expect_success 'property deltas supported' '
 	test_cmp expect actual
 '
 
-test_expect_success 'properties on /' '
+test_expect_success PIPE 'properties on /' '
 	reinit_git &&
 	cat <<-\EOF >expect &&
 	OBJID
@@ -733,8 +849,7 @@ test_expect_success 'properties on /' '
 
 	PROPS-END
 	EOF
-	test-svn-fe changeroot.dump >stream &&
-	git fast-import <stream &&
+	try_dump changeroot.dump &&
 	{
 		git rev-list HEAD |
 		git diff-tree --root --always --stdin |
@@ -743,7 +858,7 @@ test_expect_success 'properties on /' '
 	test_cmp expect actual
 '
 
-test_expect_success 'deltas for typechange' '
+test_expect_success PIPE 'deltas for typechange' '
 	reinit_git &&
 	cat >expect <<-\EOF &&
 	OBJID
@@ -819,8 +934,7 @@ test_expect_success 'deltas for typechange' '
 	PROPS-END
 	link testing 321
 	EOF
-	test-svn-fe deleteprop.dump >stream &&
-	git fast-import <stream &&
+	try_dump deleteprop.dump &&
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
@@ -829,6 +943,143 @@ test_expect_success 'deltas for typechange' '
 	test_cmp expect actual
 '
 
+test_expect_success PIPE 'deltas need not consume the whole preimage' '
+	reinit_git &&
+	cat >expect <<-\EOF &&
+	OBJID
+	:120000 100644 OBJID OBJID T	postimage
+	OBJID
+	:100644 120000 OBJID OBJID T	postimage
+	OBJID
+	:000000 100644 OBJID OBJID A	postimage
+	EOF
+	echo "first preimage" >expect.1 &&
+	printf target >expect.2 &&
+	printf lnk >expect.3 &&
+	{
+		printf "SVNQ%b%b%b" "QQ\017\001\017" "\0217" "first preimage\n" |
+		q_to_nul
+	} >delta.1 &&
+	{
+		properties svn:special "*" &&
+		echo PROPS-END
+	} >symlink.props &&
+	{
+		printf "SVNQ%b%b%b" "Q\002\013\004\012" "\0201\001\001\0211" "lnk target" |
+		q_to_nul
+	} >delta.2 &&
+	{
+		printf "SVNQ%b%b" "Q\004\003\004Q" "\001Q\002\002" |
+		q_to_nul
+	} >delta.3 &&
+	{
+		cat <<-\EOF &&
+		SVN-fs-dump-format-version: 3
+
+		Revision-number: 1
+		Prop-content-length: 10
+		Content-length: 10
+
+		PROPS-END
+
+		Node-path: postimage
+		Node-kind: file
+		Node-action: add
+		Text-delta: true
+		Prop-content-length: 10
+		EOF
+		echo Text-content-length: $(wc -c <delta.1) &&
+		echo Content-length: $((10 + $(wc -c <delta.1))) &&
+		echo &&
+		echo PROPS-END &&
+		cat delta.1 &&
+		cat <<-\EOF &&
+
+		Revision-number: 2
+		Prop-content-length: 10
+		Content-length: 10
+
+		PROPS-END
+
+		Node-path: postimage
+		Node-kind: file
+		Node-action: change
+		Text-delta: true
+		EOF
+		echo Prop-content-length: $(wc -c <symlink.props) &&
+		echo Text-content-length: $(wc -c <delta.2) &&
+		echo Content-length: $(($(wc -c <symlink.props) + $(wc -c <delta.2))) &&
+		echo &&
+		cat symlink.props &&
+		cat delta.2 &&
+		cat <<-\EOF &&
+
+		Revision-number: 3
+		Prop-content-length: 10
+		Content-length: 10
+
+		PROPS-END
+
+		Node-path: postimage
+		Node-kind: file
+		Node-action: change
+		Text-delta: true
+		Prop-content-length: 10
+		EOF
+		echo Text-content-length: $(wc -c <delta.3) &&
+		echo Content-length: $((10 + $(wc -c <delta.3))) &&
+		echo &&
+		echo PROPS-END &&
+		cat delta.3 &&
+		echo
+	} >deltapartial.dump &&
+	try_dump deltapartial.dump &&
+	{
+		git rev-list HEAD |
+		git diff-tree --root --stdin |
+		sed "s/$_x40/OBJID/g"
+	} >actual &&
+	test_cmp expect actual &&
+	git show HEAD:postimage >actual.3 &&
+	git show HEAD^:postimage >actual.2 &&
+	git show HEAD^^:postimage >actual.1 &&
+	test_cmp expect.1 actual.1 &&
+	test_cmp expect.2 actual.2 &&
+	test_cmp expect.3 actual.3
+'
+
+test_expect_success PIPE 'no hang for delta trying to read past end of preimage' '
+	reinit_git &&
+	{
+		# COPY 1
+		printf "SVNQ%b%b" "Q\001\001\002Q" "\001Q" |
+		q_to_nul
+	} >greedy.delta &&
+	{
+		cat <<-\EOF &&
+		SVN-fs-dump-format-version: 3
+
+		Revision-number: 1
+		Prop-content-length: 10
+		Content-length: 10
+
+		PROPS-END
+
+		Node-path: bootstrap
+		Node-kind: file
+		Node-action: add
+		Text-delta: true
+		Prop-content-length: 10
+		EOF
+		echo Text-content-length: $(wc -c <greedy.delta) &&
+		echo Content-length: $((10 + $(wc -c <greedy.delta))) &&
+		echo &&
+		echo PROPS-END &&
+		cat greedy.delta &&
+		echo
+	} >greedydelta.dump &&
+	try_dump greedydelta.dump must_fail might_fail
+'
 
 test_expect_success 'set up svn repo' '
 	svnconf=$PWD/svnconf &&
@@ -844,12 +1095,12 @@ test_expect_success 'set up svn repo' '
 	fi
 '
 
-test_expect_success SVNREPO 't9135/svn.dump' '
-	git init simple-git &&
-	test-svn-fe "$TEST_DIRECTORY/t9135/svn.dump" >simple.fe &&
+test_expect_success SVNREPO,PIPE 't9135/svn.dump' '
+	mkdir -p simple-git &&
 	(
 		cd simple-git &&
-		git fast-import <../simple.fe
+		reinit_git &&
+		try_dump "$TEST_DIRECTORY/t9135/svn.dump"
 	) &&
 	(
 		cd simple-svnco &&
diff --git a/t/t9011-svn-da.sh b/t/t9011-svn-da.sh
new file mode 100755
index 0000000000..b38d16f9db
--- /dev/null
+++ b/t/t9011-svn-da.sh
@@ -0,0 +1,248 @@
+#!/bin/sh
+
+test_description='test parsing of svndiff0 files
+
+Using the "test-svn-fe -d" helper, check that svn-fe correctly
+interprets deltas using various facilities (some from the spec,
+some only learned from practice).
+'
+. ./test-lib.sh
+
+>empty
+printf foo >preimage
+
+test_expect_success 'reject empty delta' '
+	test_must_fail test-svn-fe -d preimage empty 0
+'
+
+test_expect_success 'delta can empty file' '
+	printf "SVNQ" | q_to_nul >clear.delta &&
+	test-svn-fe -d preimage clear.delta 4 >actual &&
+	test_cmp empty actual
+'
+
+test_expect_success 'reject svndiff2' '
+	printf "SVN\002" >bad.filetype &&
+	test_must_fail test-svn-fe -d preimage bad.filetype 4
+'
+
+test_expect_success 'one-window empty delta' '
+	printf "SVNQ%s" "QQQQQ" | q_to_nul >clear.onewindow &&
+	test-svn-fe -d preimage clear.onewindow 9 >actual &&
+	test_cmp empty actual
+'
+
+test_expect_success 'reject incomplete window header' '
+	printf "SVNQ%s" "QQQQQ" | q_to_nul >clear.onewindow &&
+	printf "SVNQ%s" "QQ" | q_to_nul >clear.partialwindow &&
+	test_must_fail test-svn-fe -d preimage clear.onewindow 6 &&
+	test_must_fail test-svn-fe -d preimage clear.partialwindow 6
+'
+
+test_expect_success 'reject declared delta longer than actual delta' '
+	printf "SVNQ%s" "QQQQQ" | q_to_nul >clear.onewindow &&
+	printf "SVNQ%s" "QQ" | q_to_nul >clear.partialwindow &&
+	test_must_fail test-svn-fe -d preimage clear.onewindow 14 &&
+	test_must_fail test-svn-fe -d preimage clear.partialwindow 9
+'
+
+test_expect_success 'two-window empty delta' '
+	printf "SVNQ%s%s" "QQQQQ" "QQQQQ" | q_to_nul >clear.twowindow &&
+	test-svn-fe -d preimage clear.twowindow 14 >actual &&
+	test_must_fail test-svn-fe -d preimage clear.twowindow 13 &&
+	test_cmp empty actual
+'
+
+test_expect_success 'noisy zeroes' '
+	printf "SVNQ%s" \
+		"RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRQQQQQ" |
+		tr R "\200" |
+		q_to_nul >clear.noisy &&
+	len=$(wc -c <clear.noisy) &&
+	test-svn-fe -d preimage clear.noisy $len &&
+	test_cmp empty actual
+'
+
+test_expect_success 'reject variable-length int in magic' '
+	printf "SVNRQ" | tr R "\200" | q_to_nul >clear.badmagic &&
+	test_must_fail test-svn-fe -d preimage clear.badmagic 5
+'
+
+test_expect_success 'reject truncated integer' '
+	printf "SVNQ%s%s" "QQQQQ" "QQQQRRQ" |
+		tr R "\200" |
+		q_to_nul >clear.fullint &&
+	printf "SVNQ%s%s" "QQQQQ" "QQQQRR" |
+		tr RT "\201" |
+		q_to_nul >clear.partialint &&
+	test_must_fail test-svn-fe -d preimage clear.fullint 15 &&
+	test-svn-fe -d preimage clear.fullint 16 &&
+	test_must_fail test-svn-fe -d preimage clear.partialint 15
+'
+
+test_expect_success 'nonempty (but unused) preimage view' '
+	printf "SVNQ%b" "Q\003QQQ" | q_to_nul >clear.readpreimage &&
+	test-svn-fe -d preimage clear.readpreimage 9 >actual &&
+	test_cmp empty actual
+'
+
+test_expect_success 'preimage view: right endpoint cannot backtrack' '
+	printf "SVNQ%b%b" "Q\003QQQ" "Q\002QQQ" |
+		q_to_nul >clear.backtrack &&
+	test_must_fail test-svn-fe -d preimage clear.backtrack 14
+'
+
+test_expect_success 'preimage view: left endpoint can advance' '
+	printf "SVNQ%b%b" "Q\003QQQ" "\001\002QQQ" |
+		q_to_nul >clear.preshrink &&
+	printf "SVNQ%b%b" "Q\003QQQ" "\001\001QQQ" |
+		q_to_nul >clear.shrinkbacktrack &&
+	test-svn-fe -d preimage clear.preshrink 14 >actual &&
+	test_must_fail test-svn-fe -d preimage clear.shrinkbacktrack 14 &&
+	test_cmp empty actual
+'
+
+test_expect_success 'preimage view: offsets compared by value' '
+	printf "SVNQ%b%b" "\001\001QQQ" "\0200Q\003QQQ" |
+		q_to_nul >clear.noisybacktrack &&
+	printf "SVNQ%b%b" "\001\001QQQ" "\0200\001\002QQQ" |
+		q_to_nul >clear.noisyadvance &&
+	test_must_fail test-svn-fe -d preimage clear.noisybacktrack 15 &&
+	test-svn-fe -d preimage clear.noisyadvance 15 &&
+	test_cmp empty actual
+'
+
+test_expect_success 'preimage view: reject truncated preimage' '
+	printf "SVNQ%b" "\010QQQQ" | q_to_nul >clear.lateemptyread &&
+	printf "SVNQ%b" "\010\001QQQ" | q_to_nul >clear.latenonemptyread &&
+	printf "SVNQ%b" "\001\010QQQ" | q_to_nul >clear.longread &&
+	test_must_fail test-svn-fe -d preimage clear.lateemptyread 9 &&
+	test_must_fail test-svn-fe -d preimage clear.latenonemptyread 9 &&
+	test_must_fail test-svn-fe -d preimage clear.longread 9
+'
+
+test_expect_success 'forbid unconsumed inline data' '
+	printf "SVNQ%b%s%b%s" "QQQQ\003" "bar" "QQQQ\001" "x" |
+		q_to_nul >inline.clear &&
+	test_must_fail test-svn-fe -d preimage inline.clear 18 >actual
+'
+
+test_expect_success 'reject truncated inline data' '
+	printf "SVNQ%b%s" "QQQQ\003" "b" | q_to_nul >inline.trunc &&
+	test_must_fail test-svn-fe -d preimage inline.trunc 10
+'
+
+test_expect_success 'reject truncated inline data (after instruction section)' '
+	printf "SVNQ%b%b%s" "QQ\001\001\003" "\0201" "b" | q_to_nul >insn.trunc &&
+	test_must_fail test-svn-fe -d preimage insn.trunc 11
+'
+
+test_expect_success 'copyfrom_data' '
+	echo hi >expect &&
+	printf "SVNQ%b%b%b" "QQ\003\001\003" "\0203" "hi\n" | q_to_nul >copydat &&
+	test-svn-fe -d preimage copydat 13 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'multiple copyfrom_data' '
+	echo hi >expect &&
+	printf "SVNQ%b%b%b%b%b" "QQ\003\002\003" "\0201\0202" "hi\n" \
+		"QQQ\002Q" "\0200Q" | q_to_nul >copy.multi &&
+	len=$(wc -c <copy.multi) &&
+	test-svn-fe -d preimage copy.multi $len >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'incomplete multiple insn' '
+	printf "SVNQ%b%b%b" "QQ\003\002\003" "\0203\0200" "hi\n" |
+		q_to_nul >copy.partial &&
+	len=$(wc -c <copy.partial) &&
+	test_must_fail test-svn-fe -d preimage copy.partial $len
+'
+
+test_expect_success 'catch attempt to copy missing data' '
+	printf "SVNQ%b%b%s%b%s" "QQ\002\002\001" "\0201\0201" "X" \
+			"QQQQ\002" "YZ" |
+		q_to_nul >copy.incomplete &&
+	len=$(wc -c <copy.incomplete) &&
+	test_must_fail test-svn-fe -d preimage copy.incomplete $len
+'
+
+test_expect_success 'copyfrom target to repeat data' '
+	printf foofoo >expect &&
+	printf "SVNQ%b%b%s" "QQ\006\004\003" "\0203\0100\003Q" "foo" |
+		q_to_nul >copytarget.repeat &&
+	len=$(wc -c <copytarget.repeat) &&
+	test-svn-fe -d preimage copytarget.repeat $len >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'copyfrom target out of order' '
+	printf foooof >expect &&
+	printf "SVNQ%b%b%s" \
+		"QQ\006\007\003" "\0203\0101\002\0101\001\0101Q" "foo" |
+		q_to_nul >copytarget.reverse &&
+	len=$(wc -c <copytarget.reverse) &&
+	test-svn-fe -d preimage copytarget.reverse $len >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'catch copyfrom future' '
+	printf "SVNQ%b%b%s" "QQ\004\004\003" "\0202\0101\002\0201" "XYZ" |
+		q_to_nul >copytarget.infuture &&
+	len=$(wc -c <copytarget.infuture) &&
+	test_must_fail test-svn-fe -d preimage copytarget.infuture $len
+'
+
+test_expect_success 'copy to sustain' '
+	printf XYXYXYXYXYXZ >expect &&
+	printf "SVNQ%b%b%s" "QQ\014\004\003" "\0202\0111Q\0201" "XYZ" |
+		q_to_nul >copytarget.sustain &&
+	len=$(wc -c <copytarget.sustain) &&
+	test-svn-fe -d preimage copytarget.sustain $len >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'catch copy that overflows' '
+	printf "SVNQ%b%b%s" "QQ\003\003\001" "\0201\0177Q" X |
+		q_to_nul >copytarget.overflow &&
+	len=$(wc -c <copytarget.overflow) &&
+	test_must_fail test-svn-fe -d preimage copytarget.overflow $len
+'
+
+test_expect_success 'copyfrom source' '
+	printf foo >expect &&
+	printf "SVNQ%b%b" "Q\003\003\002Q" "\003Q" | q_to_nul >copysource.all &&
+	test-svn-fe -d preimage copysource.all 11 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'copy backwards' '
+	printf oof >expect &&
+	printf "SVNQ%b%b" "Q\003\003\006Q" "\001\002\001\001\001Q" |
+		q_to_nul >copysource.rev &&
+	test-svn-fe -d preimage copysource.rev 15 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'offsets are relative to window' '
+	printf fo >expect &&
+	printf "SVNQ%b%b%b%b" "Q\003\001\002Q" "\001Q" \
+		"\002\001\001\002Q" "\001Q" |
+		q_to_nul >copysource.two &&
+	test-svn-fe -d preimage copysource.two 18 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'example from notes/svndiff' '
+	printf aaaaccccdddddddd >expect &&
+	printf aaaabbbbcccc >source &&
+	printf "SVNQ%b%b%s" "Q\014\020\007\001" \
+		"\004Q\004\010\0201\0107\010" d |
+		q_to_nul >delta.example &&
+	len=$(wc -c <delta.example) &&
+	test-svn-fe -d source delta.example $len >actual &&
+	test_cmp expect actual
+'
+
+test_done