block: Finish deprecation of 'qemu-img convert -n -o'

It's been two releases since we started warning; time to make the
combination an error as promised.  There was no iotest coverage, so
add some.

While touching the documentation, tweak another section heading for
consistent style.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-3-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

4 files changed, 21 insertions, 12 deletions

diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
index 58a9aeb..aa9fdc8 100644
--- a/docs/system/deprecated.rst
+++ b/docs/system/deprecated.rst
@@ -427,14 +427,6 @@ kernel in 2018, and has also been dropped from glibc.
 Related binaries
 ----------------
 
-``qemu-img convert -n -o`` (since 4.2.0)
-''''''''''''''''''''''''''''''''''''''''
-
-All options specified in ``-o`` are image creation options, so
-they have no effect when used with ``-n`` to skip image creation.
-Silently ignored options can be confusing, so this combination of
-options will be made an error in future versions.
-
 Backwards compatibility
 -----------------------
 
@@ -540,8 +532,8 @@ spec you can use the ``-cpu rv64gcsu,priv_spec=v1.10.0`` command line argument.
 Related binaries
 ----------------
 
-``qemu-nbd --partition`` (removed in 5.0.0)
-'''''''''''''''''''''''''''''''''''''''''''
+``qemu-nbd --partition`` (removed in 5.0)
+'''''''''''''''''''''''''''''''''''''''''
 
 The ``qemu-nbd --partition $digit`` code (also spelled ``-P``)
 could only handle MBR partitions, and never correctly handled logical
@@ -557,6 +549,12 @@ can be rewritten as::
 
   qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.file.driver=file,file.file.filename=file.qcow2
 
+``qemu-img convert -n -o`` (removed in 5.1)
+'''''''''''''''''''''''''''''''''''''''''''
+
+All options specified in ``-o`` are image creation options, so
+they are now rejected when used with ``-n`` to skip image creation.
+
 Command line options
 --------------------
 
diff --git a/qemu-img.c b/qemu-img.c
index 4548dbf..46d2796 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2364,8 +2364,8 @@ static int img_convert(int argc, char **argv)
     }
 
     if (skip_create && options) {
-        warn_report("-o has no effect when skipping image creation");
-        warn_report("This will become an error in future QEMU versions.");
+        error_report("-o has no effect when skipping image creation");
+        goto fail_getopt;
     }
 
     if (s.has_zero_init && !skip_create) {
diff --git a/tests/qemu-iotests/122 b/tests/qemu-iotests/122
index f7a3ae6..2dc16b2 100755
--- a/tests/qemu-iotests/122
+++ b/tests/qemu-iotests/122
@@ -290,6 +290,13 @@ TEST_IMG="$TEST_IMG".orig _make_test_img 64M
 # backing file"
 $QEMU_IMG convert -O $IMGFMT -B "$TEST_IMG".base -n "$TEST_IMG" "$TEST_IMG".orig
 
+echo
+echo '=== -n incompatible with -o ==='
+echo
+
+$QEMU_IMG convert -O $IMGFMT -o preallocation=metadata -n \
+	  "$TEST_IMG" "$TEST_IMG".orig && echo "unexpected success"
+
 # success, all done
 echo '*** done'
 rm -f $seq.full
diff --git a/tests/qemu-iotests/122.out b/tests/qemu-iotests/122.out
index 1a35951..c2e154a 100644
--- a/tests/qemu-iotests/122.out
+++ b/tests/qemu-iotests/122.out
@@ -233,4 +233,8 @@ Images are identical.
 
 Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=67108864
 Formatting 'TEST_DIR/t.IMGFMT.orig', fmt=IMGFMT size=67108864
+
+=== -n incompatible with -o ===
+
+qemu-img: -o has no effect when skipping image creation
 *** done