git-p4: add option to keep empty commits

A changelist that contains only excluded files due to a client spec was
imported as an empty commit. Fix that issue by ignoring these commits.
Add option "git-p4.keepEmptyCommits" to make the previous behavior
available.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Helped-by: Pete Harlan
Acked-by: Luke Diamand <luke@diamand.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-p4.txt

@@ -510,6 +510,10 @@ git-p4.useClientSpec::
 	option '--use-client-spec'.  See the "CLIENT SPEC" section above.
 	This variable is a boolean, not the name of a p4 client.
 
+git-p4.keepEmptyCommits::
+	A changelist that contains only excluded files will be imported
+	as an empty commit if this boolean option is set to true.
+
 Submit variables
 ~~~~~~~~~~~~~~~~
 git-p4.detectRenames::

git-p4.py

@@ -2235,12 +2235,6 @@ def streamP4Files(self, files):
         filesToDelete = []
 
         for f in files:
-            # if using a client spec, only add the files that have
-            # a path in the client
-            if self.clientSpecDirs:
-                if self.clientSpecDirs.map_in_client(f['path']) == "":
-                    continue
-
             filesForCommit.append(f)
             if f['action'] in self.delete_actions:
                 filesToDelete.append(f)
@@ -2308,25 +2302,41 @@ def streamTag(self, gitStream, labelName, labelDetails, commit, epoch):
         gitStream.write(description)
         gitStream.write("\n")
 
+    def inClientSpec(self, path):
+        if not self.clientSpecDirs:
+            return True
+        inClientSpec = self.clientSpecDirs.map_in_client(path)
+        if not inClientSpec and self.verbose:
+            print('Ignoring file outside of client spec: {0}'.format(path))
+        return inClientSpec
+
+    def hasBranchPrefix(self, path):
+        if not self.branchPrefixes:
+            return True
+        hasPrefix = [p for p in self.branchPrefixes
+                        if p4PathStartsWith(path, p)]
+        if hasPrefix and self.verbose:
+            print('Ignoring file outside of prefix: {0}'.format(path))
+        return hasPrefix
+
     def commit(self, details, files, branch, parent = ""):
         epoch = details["time"]
         author = details["user"]
 
         if self.verbose:
-            print "commit into %s" % branch
-
-        # start with reading files; if that fails, we should not
-        # create a commit.
-        new_files = []
-        for f in files:
-            if [p for p in self.branchPrefixes if p4PathStartsWith(f['path'], p)]:
-                new_files.append (f)
-            else:
-                sys.stderr.write("Ignoring file outside of prefix: %s\n" % f['path'])
+            print('commit into {0}'.format(branch))
 
         if self.clientSpecDirs:
             self.clientSpecDirs.update_client_spec_path_cache(files)
 
+        files = [f for f in files
+            if self.inClientSpec(f['path']) and self.hasBranchPrefix(f['path'])]
+
+        if not files and not gitConfigBool('git-p4.keepEmptyCommits'):
+            print('Ignoring revision {0} as it would produce an empty commit.'
+                .format(details['change']))
+            return
+
         self.gitStream.write("commit %s\n" % branch)
 #        gitStream.write("mark :%s\n" % details["change"])
         self.committedChanges.add(int(details["change"]))
@@ -2350,7 +2360,7 @@ def commit(self, details, files, branch, parent = ""):
                 print "parent %s" % parent
             self.gitStream.write("from %s\n" % parent)
 
-        self.streamP4Files(new_files)
+        self.streamP4Files(files)
         self.gitStream.write("\n")
 
         change = int(details["change"])

t/t9826-git-p4-keep-empty-commits.sh

@@ -0,0 +1,134 @@
+#!/bin/sh
+
+test_description='Clone repositories and keep empty commits'
+
+. ./lib-git-p4.sh
+
+test_expect_success 'start p4d' '
+	start_p4d
+'
+
+test_expect_success 'Create a repo' '
+	client_view "//depot/... //client/..." &&
+	(
+		cd "$cli" &&
+
+		mkdir -p subdir &&
+
+		>subdir/file1.txt &&
+		p4 add subdir/file1.txt &&
+		p4 submit -d "Add file 1" &&
+
+		>file2.txt &&
+		p4 add file2.txt &&
+		p4 submit -d "Add file 2" &&
+
+		>subdir/file3.txt &&
+		p4 add subdir/file3.txt &&
+		p4 submit -d "Add file 3" &&
+
+		>file4.txt &&
+		p4 add file4.txt &&
+		p4 submit -d "Add file 4" &&
+
+		p4 delete subdir/file3.txt &&
+		p4 submit -d "Remove file 3" &&
+
+		p4 delete file4.txt &&
+		p4 submit -d "Remove file 4"
+	)
+'
+
+test_expect_success 'Clone repo root path with all history' '
+	client_view "//depot/... //client/..." &&
+	test_when_finished cleanup_git &&
+	(
+		cd "$git" &&
+		git init . &&
+		git p4 clone --use-client-spec --destination="$git" //depot@all &&
+		cat >expect <<-\EOF &&
+Remove file 4
+[git-p4: depot-paths = "//depot/": change = 6]
+
+Remove file 3
+[git-p4: depot-paths = "//depot/": change = 5]
+
+Add file 4
+[git-p4: depot-paths = "//depot/": change = 4]
+
+Add file 3
+[git-p4: depot-paths = "//depot/": change = 3]
+
+Add file 2
+[git-p4: depot-paths = "//depot/": change = 2]
+
+Add file 1
+[git-p4: depot-paths = "//depot/": change = 1]
+
+		EOF
+		git log --format=%B >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'Clone repo subdir with all history but keep empty commits' '
+	client_view "//depot/subdir/... //client/subdir/..." &&
+	test_when_finished cleanup_git &&
+	(
+		cd "$git" &&
+		git init . &&
+		git config git-p4.keepEmptyCommits true &&
+		git p4 clone --use-client-spec --destination="$git" //depot@all &&
+		cat >expect <<-\EOF &&
+Remove file 4
+[git-p4: depot-paths = "//depot/": change = 6]
+
+Remove file 3
+[git-p4: depot-paths = "//depot/": change = 5]
+
+Add file 4
+[git-p4: depot-paths = "//depot/": change = 4]
+
+Add file 3
+[git-p4: depot-paths = "//depot/": change = 3]
+
+Add file 2
+[git-p4: depot-paths = "//depot/": change = 2]
+
+Add file 1
+[git-p4: depot-paths = "//depot/": change = 1]
+
+		EOF
+		git log --format=%B >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'Clone repo subdir with all history' '
+	client_view "//depot/subdir/... //client/subdir/..." &&
+	test_when_finished cleanup_git &&
+	(
+		cd "$git" &&
+		git init . &&
+		git p4 clone --use-client-spec --destination="$git" --verbose //depot@all &&
+		cat >expect <<-\EOF &&
+Remove file 3
+[git-p4: depot-paths = "//depot/": change = 5]
+
+Add file 3
+[git-p4: depot-paths = "//depot/": change = 3]
+
+Add file 1
+[git-p4: depot-paths = "//depot/": change = 1]
+
+		EOF
+		git log --format=%B >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'kill p4d' '
+	kill_p4d
+'
+
+test_done