Git 2.0: git svn: Set default --prefix='origin/' if --prefix is not g…

…iven

git-svn by default puts its Subversion-tracking refs directly in
refs/remotes/*. This runs counter to Git's convention of using
refs/remotes/$remote/* for storing remote-tracking branches.

Furthermore, combining git-svn with regular git remotes run the risk of
clobbering refs under refs/remotes (e.g. if you have a git remote
called "tags" with a "v1" branch, it will overlap with the git-svn's
tracking branch for the "v1" tag from Subversion.

Even though the git-svn refs stored in refs/remotes/* are not "proper"
remote-tracking branches (since they are not covered by a proper git
remote's refspec), they clearly represent a similar concept, and would
benefit from following the same convention.

For example, if git-svn tracks Subversion branch "foo" at
refs/remotes/foo, and you create a local branch refs/heads/foo to add
some commits to be pushed back to Subversion (using "git svn dcommit),
then it is clearly unhelpful of Git to throw

  warning: refname 'foo' is ambiguous.

every time you checkout, rebase, or otherwise interact with the branch.

The existing workaround for this is to supply the --prefix=quux/ to
git svn init/clone, so that git-svn's tracking branches end up in
refs/remotes/quux/* instead of refs/remotes/*. However, encouraging
users to specify --prefix to work around a design flaw in git-svn is
suboptimal, and not a long term solution to the problem. Instead,
git-svn should default to use a non-empty prefix that saves
unsuspecting users from the inconveniences described above.

This patch will only affect newly created git-svn setups, as the
--prefix option only applies to git svn init (and git svn clone).
Existing git-svn setups will continue with their existing (lack of)
prefix. Also, if anyone somehow prefers git-svn's old layout, they
can recreate that by explicitly passing an empty prefix (--prefix "")
on the git svn init/clone command line.

The patch changes the default value for --prefix from "" to "origin/",
updates the git-svn manual page, and fixes the fallout in the git-svn
testcases.

(Note that this patch might be easier to review using the --word-diff
and --word-diff-regex=. diff options.)

[ew: squashed description of <= 1.9 behavior into manpage]

Suggested-by: Thomas Ferris Nicolaisen <tfnico@gmail.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Eric Wong <normalperson@yhbt.net>

Documentation/git-svn.txt

@@ -86,13 +86,11 @@ COMMANDS
 	(refs/remotes/$remote/*). Setting a prefix is also useful
 	if you wish to track multiple projects that share a common
 	repository.
+	By default, the prefix is set to 'origin/'.
 +
-NOTE: In Git v2.0, the default prefix will CHANGE from "" (no prefix)
-to "origin/". This is done to put SVN-tracking refs at
-"refs/remotes/origin/*" instead of "refs/remotes/*", and make them
-more compatible with how Git's own remote-tracking refs are organized
-(i.e. refs/remotes/$remote/*). You can enjoy the same benefits today,
-by using the --prefix option.
+NOTE: Before Git v2.0, the default prefix was "" (no prefix). This
+meant that SVN-tracking refs were put at "refs/remotes/*", which is
+incompatible with how Git's own remote-tracking refs are organized.
 
 --ignore-paths=<regex>;;
 	When passed to 'init' or 'clone' this regular expression will
@@ -994,16 +992,6 @@ without giving any repository layout options.  If the full history with
 branches and tags is required, the options '--trunk' / '--branches' /
 '--tags' must be used.
 
-When using the options for describing the repository layout (--trunk,
---tags, --branches, --stdlayout), please also specify the --prefix
-option (e.g. '--prefix=origin/') to cause your SVN-tracking refs to be
-placed at refs/remotes/origin/* rather than the default refs/remotes/*.
-The former is more compatible with the layout of Git's "regular"
-remote-tracking refs (refs/remotes/$remote/*), and may potentially
-prevent similarly named SVN branches and Git remotes from clobbering
-each other. In Git v2.0 the default prefix used (i.e. when no --prefix
-is given) will change from "" (no prefix) to "origin/".
-
 When using multiple --branches or --tags, 'git svn' does not automatically
 handle name collisions (for example, if two branches from different paths have
 the same name, or if a branch and a tag have the same name).  In these cases,

git-svn.perl

@@ -1389,17 +1389,7 @@ sub cmd_multi_init {
 		usage(1);
 	}
 
-	unless (defined $_prefix) {
-		$_prefix = '';
-		warn <<EOF
-WARNING: --prefix is not given, defaulting to empty prefix.
-         This is probably not what you want! In order to stay compatible
-         with regular remote-tracking refs, provide a prefix like
-         --prefix=origin/ (remember the trailing slash), which will cause
-         the SVN-tracking refs to be placed at refs/remotes/origin/*.
-NOTE: In Git v2.0, the default prefix will change from empty to 'origin/'.
-EOF
-	}
+	$_prefix = 'origin/' unless defined $_prefix;
 	if (defined $url) {
 		$url = canonicalize_url($url);
 		init_subdir(@_);

t/t9107-git-svn-migrate.sh

@@ -45,42 +45,42 @@ test_expect_success 'initialize old-style (v0) git svn layout' '
 test_expect_success 'initialize a multi-repository repo' '
 	git svn init "$svnrepo" -T trunk -t tags -b branches &&
 	git config --get-all svn-remote.svn.fetch > fetch.out &&
-	grep "^trunk:refs/remotes/trunk$" fetch.out &&
+	grep "^trunk:refs/remotes/origin/trunk$" fetch.out &&
 	test -n "`git config --get svn-remote.svn.branches \
-	            "^branches/\*:refs/remotes/\*$"`" &&
+	            "^branches/\*:refs/remotes/origin/\*$"`" &&
 	test -n "`git config --get svn-remote.svn.tags \
-	            "^tags/\*:refs/remotes/tags/\*$"`" &&
+	            "^tags/\*:refs/remotes/origin/tags/\*$"`" &&
 	git config --unset svn-remote.svn.branches \
-	                        "^branches/\*:refs/remotes/\*$" &&
+	                        "^branches/\*:refs/remotes/origin/\*$" &&
 	git config --unset svn-remote.svn.tags \
-	                        "^tags/\*:refs/remotes/tags/\*$" &&
-	git config --add svn-remote.svn.fetch "branches/a:refs/remotes/a" &&
-	git config --add svn-remote.svn.fetch "branches/b:refs/remotes/b" &&
+	                        "^tags/\*:refs/remotes/origin/tags/\*$" &&
+	git config --add svn-remote.svn.fetch "branches/a:refs/remotes/origin/a" &&
+	git config --add svn-remote.svn.fetch "branches/b:refs/remotes/origin/b" &&
 	for i in tags/0.1 tags/0.2 tags/0.3; do
 		git config --add svn-remote.svn.fetch \
-		                 $i:refs/remotes/$i || exit 1; done &&
+		                 $i:refs/remotes/origin/$i || exit 1; done &&
 	git config --get-all svn-remote.svn.fetch > fetch.out &&
-	grep "^trunk:refs/remotes/trunk$" fetch.out &&
-	grep "^branches/a:refs/remotes/a$" fetch.out &&
-	grep "^branches/b:refs/remotes/b$" fetch.out &&
-	grep "^tags/0\.1:refs/remotes/tags/0\.1$" fetch.out &&
-	grep "^tags/0\.2:refs/remotes/tags/0\.2$" fetch.out &&
-	grep "^tags/0\.3:refs/remotes/tags/0\.3$" fetch.out &&
+	grep "^trunk:refs/remotes/origin/trunk$" fetch.out &&
+	grep "^branches/a:refs/remotes/origin/a$" fetch.out &&
+	grep "^branches/b:refs/remotes/origin/b$" fetch.out &&
+	grep "^tags/0\.1:refs/remotes/origin/tags/0\.1$" fetch.out &&
+	grep "^tags/0\.2:refs/remotes/origin/tags/0\.2$" fetch.out &&
+	grep "^tags/0\.3:refs/remotes/origin/tags/0\.3$" fetch.out &&
 	grep "^:refs/${remotes_git_svn}" fetch.out
 	'
 
 # refs should all be different, but the trees should all be the same:
 test_expect_success 'multi-fetch works on partial urls + paths' "
 	git svn multi-fetch &&
 	for i in trunk a b tags/0.1 tags/0.2 tags/0.3; do
-		git rev-parse --verify refs/remotes/\$i^0 >> refs.out || exit 1;
+		git rev-parse --verify refs/remotes/origin/\$i^0 >> refs.out || exit 1;
 	    done &&
 	test -z \"\`sort < refs.out | uniq -d\`\" &&
 	for i in trunk a b tags/0.1 tags/0.2 tags/0.3; do
 	  for j in trunk a b tags/0.1 tags/0.2 tags/0.3; do
 		if test \$j != \$i; then continue; fi
-	    test -z \"\`git diff refs/remotes/\$i \
-	                         refs/remotes/\$j\`\" ||exit 1; done; done
+	    test -z \"\`git diff refs/remotes/origin/\$i \
+	                         refs/remotes/origin/\$j\`\" ||exit 1; done; done
 	"
 
 test_expect_success 'migrate --minimize on old inited layout' '
@@ -98,27 +98,27 @@ test_expect_success 'migrate --minimize on old inited layout' '
 	git svn migrate --minimize &&
 	test -z "`git config -l | grep "^svn-remote\.git-svn\."`" &&
 	git config --get-all svn-remote.svn.fetch > fetch.out &&
-	grep "^trunk:refs/remotes/trunk$" fetch.out &&
-	grep "^branches/a:refs/remotes/a$" fetch.out &&
-	grep "^branches/b:refs/remotes/b$" fetch.out &&
-	grep "^tags/0\.1:refs/remotes/tags/0\.1$" fetch.out &&
-	grep "^tags/0\.2:refs/remotes/tags/0\.2$" fetch.out &&
-	grep "^tags/0\.3:refs/remotes/tags/0\.3$" fetch.out &&
+	grep "^trunk:refs/remotes/origin/trunk$" fetch.out &&
+	grep "^branches/a:refs/remotes/origin/a$" fetch.out &&
+	grep "^branches/b:refs/remotes/origin/b$" fetch.out &&
+	grep "^tags/0\.1:refs/remotes/origin/tags/0\.1$" fetch.out &&
+	grep "^tags/0\.2:refs/remotes/origin/tags/0\.2$" fetch.out &&
+	grep "^tags/0\.3:refs/remotes/origin/tags/0\.3$" fetch.out &&
 	grep "^:refs/${remotes_git_svn}" fetch.out
 	'
 
 test_expect_success  ".rev_db auto-converted to .rev_map.UUID" '
 	git svn fetch -i trunk &&
-	test -z "$(ls "$GIT_DIR"/svn/refs/remotes/trunk/.rev_db.* 2>/dev/null)" &&
-	expect="$(ls "$GIT_DIR"/svn/refs/remotes/trunk/.rev_map.*)" &&
+	test -z "$(ls "$GIT_DIR"/svn/refs/remotes/origin/trunk/.rev_db.* 2>/dev/null)" &&
+	expect="$(ls "$GIT_DIR"/svn/refs/remotes/origin/trunk/.rev_map.*)" &&
 	test -n "$expect" &&
 	rev_db="$(echo $expect | sed -e "s,_map,_db,")" &&
 	convert_to_rev_db "$expect" "$rev_db" &&
 	rm -f "$expect" &&
 	test -f "$rev_db" &&
 	git svn fetch -i trunk &&
-	test -z "$(ls "$GIT_DIR"/svn/refs/remotes/trunk/.rev_db.* 2>/dev/null)" &&
-	test ! -e "$GIT_DIR"/svn/refs/remotes/trunk/.rev_db &&
+	test -z "$(ls "$GIT_DIR"/svn/refs/remotes/origin/trunk/.rev_db.* 2>/dev/null)" &&
+	test ! -e "$GIT_DIR"/svn/refs/remotes/origin/trunk/.rev_db &&
 	test -f "$expect"
 	'
 

t/t9114-git-svn-dcommit-merge.sh

@@ -48,7 +48,7 @@ test_expect_success 'setup svn repository' '
 test_expect_success 'setup git mirror and merge' '
 	git svn init "$svnrepo" -t tags -T trunk -b branches &&
 	git svn fetch &&
-	git checkout -b svn remotes/trunk &&
+	git checkout -b svn remotes/origin/trunk &&
 	git checkout -b merge &&
 	echo new file > new_file &&
 	git add new_file &&
@@ -81,7 +81,7 @@ test_debug 'gitk --all & sleep 1'
 
 test_expect_success 'verify post-merge ancestry' "
 	test x\`git rev-parse --verify refs/heads/svn\` = \
-	     x\`git rev-parse --verify refs/remotes/trunk \` &&
+	     x\`git rev-parse --verify refs/remotes/origin/trunk \` &&
 	test x\`git rev-parse --verify refs/heads/svn^2\` = \
 	     x\`git rev-parse --verify refs/heads/merge\` &&
 	git cat-file commit refs/heads/svn^ | grep '^friend$'

t/t9116-git-svn-log.sh

@@ -20,20 +20,20 @@ test_expect_success 'setup repository and import' '
 	) &&
 	git svn init "$svnrepo" -T trunk -b branches -t tags &&
 	git svn fetch &&
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	echo bye >> README &&
 	git commit -a -m bye &&
 	git svn dcommit &&
-	git reset --hard a &&
+	git reset --hard origin/a &&
 	echo why >> FEEDME &&
 	git update-index --add FEEDME &&
 	git commit -m feedme &&
 	git svn dcommit &&
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	echo aye >> README &&
 	git commit -a -m aye &&
 	git svn dcommit &&
-	git reset --hard b &&
+	git reset --hard origin/b &&
 	echo spy >> README &&
 	git commit -a -m spy &&
 	echo try >> README &&
@@ -42,34 +42,34 @@ test_expect_success 'setup repository and import' '
 	'
 
 test_expect_success 'run log' "
-	git reset --hard a &&
-	git svn log -r2 trunk | grep ^r2 &&
-	git svn log -r4 trunk | grep ^r4 &&
+	git reset --hard origin/a &&
+	git svn log -r2 origin/trunk | grep ^r2 &&
+	git svn log -r4 origin/trunk | grep ^r4 &&
 	git svn log -r3 | grep ^r3
 	"
 
 test_expect_success 'run log against a from trunk' "
-	git reset --hard trunk &&
-	git svn log -r3 a | grep ^r3
+	git reset --hard origin/trunk &&
+	git svn log -r3 origin/a | grep ^r3
 	"
 
 printf 'r1 \nr2 \nr4 \n' > expected-range-r1-r2-r4
 
 test_expect_success 'test ascending revision range' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 1:4 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r1-r2-r4 -
 	"
 
 test_expect_success 'test ascending revision range with --show-commit' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log --show-commit -r 1:4 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r1-r2-r4 -
 	"
 
 test_expect_success 'test ascending revision range with --show-commit (sha1)' "
 	git svn find-rev r1 >expected-range-r1-r2-r4-sha1 &&
 	git svn find-rev r2 >>expected-range-r1-r2-r4-sha1 &&
 	git svn find-rev r4 >>expected-range-r1-r2-r4-sha1 &&
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log --show-commit -r 1:4 | grep '^r[0-9]' | cut -d'|' -f2 >out &&
 	git rev-parse \$(cat out) >actual &&
 	test_cmp expected-range-r1-r2-r4-sha1 actual
@@ -78,67 +78,67 @@ test_expect_success 'test ascending revision range with --show-commit (sha1)' "
 printf 'r4 \nr2 \nr1 \n' > expected-range-r4-r2-r1
 
 test_expect_success 'test descending revision range' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 4:1 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r4-r2-r1 -
 	"
 
 printf 'r1 \nr2 \n' > expected-range-r1-r2
 
 test_expect_success 'test ascending revision range with unreachable revision' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 1:3 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r1-r2 -
 	"
 
 printf 'r2 \nr1 \n' > expected-range-r2-r1
 
 test_expect_success 'test descending revision range with unreachable revision' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 3:1 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r2-r1 -
 	"
 
 printf 'r2 \n' > expected-range-r2
 
 test_expect_success 'test ascending revision range with unreachable upper boundary revision and 1 commit' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 2:3 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r2 -
 	"
 
 test_expect_success 'test descending revision range with unreachable upper boundary revision and 1 commit' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 3:2 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r2 -
 	"
 
 printf 'r4 \n' > expected-range-r4
 
 test_expect_success 'test ascending revision range with unreachable lower boundary revision and 1 commit' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 3:4 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r4 -
 	"
 
 test_expect_success 'test descending revision range with unreachable lower boundary revision and 1 commit' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 4:3 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r4 -
 	"
 
 printf -- '------------------------------------------------------------------------\n' > expected-separator
 
 test_expect_success 'test ascending revision range with unreachable boundary revisions and no commits' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 5:6 | test_cmp expected-separator -
 	"
 
 test_expect_success 'test descending revision range with unreachable boundary revisions and no commits' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 6:5 | test_cmp expected-separator -
 	"
 
 test_expect_success 'test ascending revision range with unreachable boundary revisions and 1 commit' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 3:5 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r4 -
 	"
 
 test_expect_success 'test descending revision range with unreachable boundary revisions and 1 commit' "
-	git reset --hard trunk &&
+	git reset --hard origin/trunk &&
 	git svn log -r 5:3 | grep '^r[0-9]' | cut -d'|' -f1 | test_cmp expected-range-r4 -
 	"
 

t/t9117-git-svn-init-clone.sh

@@ -83,25 +83,25 @@ EOF
 	rm -f expect actual
 }
 
-test_expect_success 'init with -s/-T/-b/-t without --prefix warns' '
+test_expect_success 'init with -s/-T/-b/-t assumes --prefix=origin/' '
 	test ! -d project &&
 	git svn init -s "$svnrepo"/project project 2>warning &&
-	grep -q prefix warning &&
-	test_svn_configured_prefix "" &&
+	test_must_fail grep -q prefix warning &&
+	test_svn_configured_prefix "origin/" &&
 	rm -rf project &&
 	rm -f warning
 	'
 
-test_expect_success 'clone with -s/-T/-b/-t without --prefix warns' '
+test_expect_success 'clone with -s/-T/-b/-t assumes --prefix=origin/' '
 	test ! -d project &&
 	git svn clone -s "$svnrepo"/project 2>warning &&
-	grep -q prefix warning &&
-	test_svn_configured_prefix "" &&
+	test_must_fail grep -q prefix warning &&
+	test_svn_configured_prefix "origin/" &&
 	rm -rf project &&
 	rm -f warning
 	'
 
-test_expect_success 'init with -s/-T/-b/-t and --prefix does not warn' '
+test_expect_success 'init with -s/-T/-b/-t and --prefix="" still works' '
 	test ! -d project &&
 	git svn init -s "$svnrepo"/project project --prefix="" 2>warning &&
 	test_must_fail grep -q prefix warning &&
@@ -110,7 +110,7 @@ test_expect_success 'init with -s/-T/-b/-t and --prefix does not warn' '
 	rm -f warning
 	'
 
-test_expect_success 'clone with -s/-T/-b/-t and --prefix does not warn' '
+test_expect_success 'clone with -s/-T/-b/-t and --prefix="" still works' '
 	test ! -d project &&
 	git svn clone -s "$svnrepo"/project --prefix="" 2>warning &&
 	test_must_fail grep -q prefix warning &&