Merge branch 'tr/maint-format-patch-empty-output'

* tr/maint-format-patch-empty-output:
  Document negated forms of format-patch --to --cc --add-headers
  t4014: "no-add-headers" is actually called "no-add-header"
  t4014: invoke format-patch with --stdout where intended
  t4014: check for empty files from git format-patch --stdout

Documentation/git-format-patch.txt

@@ -166,15 +166,22 @@ will want to ensure that threading is disabled for `git send-email`.
 --to=<email>::
 	Add a `To:` header to the email headers. This is in addition
 	to any configured headers, and may be used multiple times.
+	The negated form `--no-to` discards all `To:` headers added so
+	far (from config or command line).
 
 --cc=<email>::
 	Add a `Cc:` header to the email headers. This is in addition
 	to any configured headers, and may be used multiple times.
+	The negated form `--no-cc` discards all `Cc:` headers added so
+	far (from config or command line).
 
 --add-header=<header>::
 	Add an arbitrary header to the email headers.  This is in addition
 	to any configured headers, and may be used multiple times.
-	For example, `--add-header="Organization: git-foo"`
+	For example, `--add-header="Organization: git-foo"`.
+	The negated form `--no-add-header` discards *all* (`To:`,
+	`Cc:`, and custom) headers added so far from config or command
+	line.
 
 --cover-letter::
 	In addition to the patches, generate a cover letter file

t/t4014-format-patch.sh

@@ -179,12 +179,21 @@ test_expect_success 'configuration To: header' '
 	grep "^To: R. E. Cipient <rcipient@example.com>\$" patch9
 '
 
+# check_patch <patch>: Verify that <patch> looks like a half-sane
+# patch email to avoid a false positive with !grep
+check_patch () {
+	grep -e "^From:" "$1" &&
+	grep -e "^Date:" "$1" &&
+	grep -e "^Subject:" "$1"
+}
+
 test_expect_success '--no-to overrides config.to' '
 
 	git config --replace-all format.to \
 		"R. E. Cipient <rcipient@example.com>" &&
 	git format-patch --no-to --stdout master..side |
 	sed -e "/^\$/q" >patch10 &&
+	check_patch patch10 &&
 	! grep "^To: R. E. Cipient <rcipient@example.com>\$" patch10
 '
 
@@ -195,6 +204,7 @@ test_expect_success '--no-to and --to replaces config.to' '
 	git format-patch --no-to --to="Someone Else <else@out.there>" \
 		--stdout master..side |
 	sed -e "/^\$/q" >patch11 &&
+	check_patch patch11 &&
 	! grep "^To: Someone <someone@out.there>\$" patch11 &&
 	grep "^To: Someone Else <else@out.there>\$" patch11
 '
@@ -205,15 +215,17 @@ test_expect_success '--no-cc overrides config.cc' '
 		"C. E. Cipient <rcipient@example.com>" &&
 	git format-patch --no-cc --stdout master..side |
 	sed -e "/^\$/q" >patch12 &&
+	check_patch patch12 &&
 	! grep "^Cc: C. E. Cipient <rcipient@example.com>\$" patch12
 '
 
-test_expect_success '--no-add-headers overrides config.headers' '
+test_expect_success '--no-add-header overrides config.headers' '
 
 	git config --replace-all format.headers \
 		"Header1: B. E. Cipient <rcipient@example.com>" &&
-	git format-patch --no-add-headers --stdout master..side |
+	git format-patch --no-add-header --stdout master..side |
 	sed -e "/^\$/q" >patch13 &&
+	check_patch patch13 &&
 	! grep "^Header1: B. E. Cipient <rcipient@example.com>\$" patch13
 '
 
@@ -480,6 +492,7 @@ test_expect_success 'cover-letter inherits diff options' '
 	git mv file foo &&
 	git commit -m foo &&
 	git format-patch --cover-letter -1 &&
+	check_patch 0000-cover-letter.patch &&
 	! grep "file => foo .* 0 *\$" 0000-cover-letter.patch &&
 	git format-patch --cover-letter -1 -M &&
 	grep "file => foo .* 0 *\$" 0000-cover-letter.patch
@@ -657,6 +670,7 @@ test_expect_success 'format-patch --no-signature ignores format.signature' '
 	git config format.signature "config sig" &&
 	git format-patch --stdout --signature="my sig" --no-signature \
 		-1 >output &&
+	check_patch output &&
 	! grep "config sig" output &&
 	! grep "my sig" output &&
 	! grep "^-- \$" output
@@ -673,17 +687,20 @@ test_expect_success 'format-patch --signature --cover-letter' '
 test_expect_success 'format.signature="" supresses signatures' '
 	git config format.signature "" &&
 	git format-patch --stdout -1 >output &&
+	check_patch output &&
 	! grep "^-- \$" output
 '
 
 test_expect_success 'format-patch --no-signature supresses signatures' '
 	git config --unset-all format.signature &&
 	git format-patch --stdout --no-signature -1 >output &&
+	check_patch output &&
 	! grep "^-- \$" output
 '
 
 test_expect_success 'format-patch --signature="" supresses signatures' '
-	git format-patch --signature="" -1 >output &&
+	git format-patch --stdout --signature="" -1 >output &&
+	check_patch output &&
 	! grep "^-- \$" output
 '