git-p4: test cloning with two dirs, clarify doc

Document how git-p4 currently works when specifying multiple
depot paths:

1.  No branches or directories are named.

2.  Conflicting files are silently ignored---the last change
    wins.

2.  Option --destination is required, else the last path is construed
    to be a directory.

3.  Revision specifiers must be the same on all paths for them to
    take effect.

Test this behavior.

Signed-off-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-p4.txt

@@ -276,8 +276,15 @@ p4 revision specifier on the end:
 "//depot/my/project@1,6"::
     Import only changes 1 through 6.
 
-"//depot/proj1 //depot/proj2@all"::
-    Import all changes from both named depot paths.
+"//depot/proj1@all //depot/proj2@all"::
+    Import all changes from both named depot paths into a single
+    repository.  Only files below these directories are included.
+    There is not a subdirectory in git for each "proj1" and "proj2".
+    You must use the '--destination' option when specifying more
+    than one depot path.  The revision specifier must be specified
+    identically on each depot path.  If there are files in the
+    depot paths with the same name, the path with the most recently
+    updated version of the file is the one that appears in git.
 
 See 'p4 help revisions' for the full syntax of p4 revision specifiers.
 

t/t9800-git-p4-basic.sh

@@ -65,6 +65,66 @@ test_expect_success 'git-p4 sync new branch' '
 	)
 '
 
+test_expect_success 'clone two dirs' '
+	(
+		cd "$cli" &&
+		mkdir sub1 sub2 &&
+		echo sub1/f1 >sub1/f1 &&
+		echo sub2/f2 >sub2/f2 &&
+		p4 add sub1/f1 &&
+		p4 submit -d "sub1/f1" &&
+		p4 add sub2/f2 &&
+		p4 submit -d "sub2/f2"
+	) &&
+	"$GITP4" clone --dest="$git" //depot/sub1 //depot/sub2 &&
+	test_when_finished cleanup_git &&
+	(
+		cd "$git" &&
+		git ls-files >lines &&
+		test_line_count = 2 lines &&
+		git log --oneline p4/master >lines &&
+		test_line_count = 1 lines
+	)
+'
+
+test_expect_success 'clone two dirs, @all' '
+	(
+		cd "$cli" &&
+		echo sub1/f3 >sub1/f3 &&
+		p4 add sub1/f3 &&
+		p4 submit -d "sub1/f3"
+	) &&
+	"$GITP4" clone --dest="$git" //depot/sub1@all //depot/sub2@all &&
+	test_when_finished cleanup_git &&
+	(
+		cd "$git" &&
+		git ls-files >lines &&
+		test_line_count = 3 lines &&
+		git log --oneline p4/master >lines &&
+		test_line_count = 3 lines
+	)
+'
+
+test_expect_success 'clone two dirs, @all, conflicting files' '
+	(
+		cd "$cli" &&
+		echo sub2/f3 >sub2/f3 &&
+		p4 add sub2/f3 &&
+		p4 submit -d "sub2/f3"
+	) &&
+	"$GITP4" clone --dest="$git" //depot/sub1@all //depot/sub2@all &&
+	test_when_finished cleanup_git &&
+	(
+		cd "$git" &&
+		git ls-files >lines &&
+		test_line_count = 3 lines &&
+		git log --oneline p4/master >lines &&
+		test_line_count = 4 lines &&
+		echo sub2/f3 >expected &&
+		test_cmp expected f3
+	)
+'
+
 test_expect_success 'exit when p4 fails to produce marshaled output' '
 	badp4dir="$TRASH_DIRECTORY/badp4dir" &&
 	mkdir "$badp4dir" &&