Output headers for volume ls when empty

To have consistency with other podman commands like `ps` and `images`,
`volume ls` should output its headers even when there are no volumes.

Fixes: #25911

Signed-off-by: Brent Baude <[email protected]>

Author: baude

cmd/podman/volumes/list.go

@@ -80,11 +80,8 @@ func list(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	switch {
-	case report.IsJSON(cliOpts.Format):
+	if report.IsJSON(cliOpts.Format) {
 		return outputJSON(responses)
-	case len(responses) < 1:
-		return nil
 	}
 	return outputTemplate(cmd, responses)
 }

test/e2e/prune_test.go

@@ -377,7 +377,7 @@ var _ = Describe("Podman prune", func() {
 		session = podmanTest.Podman([]string{"volume", "ls"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 
 		// One Pod should not be pruned as it was running
 		Expect(podmanTest.NumberOfPods()).To(Equal(1))

test/e2e/system_reset_test.go

@@ -55,7 +55,7 @@ var _ = Describe("podman system reset", Serial, func() {
 		session = podmanTest.Podman([]string{"volume", "ls"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 
 		session = podmanTest.Podman([]string{"container", "ls", "-q"})
 		session.WaitWithDefaultTimeout()

test/e2e/volume_ls_test.go

@@ -17,6 +17,13 @@ var _ = Describe("Podman volume ls", func() {
 	})
 
 	It("podman ls volume", func() {
+		// https://github.com/containers/podman/issues/25911
+		// Output header for volume ls even when empty
+		empty := podmanTest.PodmanExitCleanly("volume", "ls")
+		Expect(empty.OutputToString()).To(ContainSubstring("DRIVER"))
+		Expect(empty.OutputToString()).To(ContainSubstring("VOLUME NAME"))
+		Expect(empty.ErrorToStringArray()).To(HaveLen(1))
+
 		session := podmanTest.Podman([]string{"volume", "create", "myvol"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
@@ -94,7 +101,6 @@ var _ = Describe("Podman volume ls", func() {
 		session = podmanTest.Podman([]string{"volume", "ls", "--filter", "label=foo=foo"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
 
 		session = podmanTest.Podman([]string{"volume", "ls", "--filter", "label=foo=bar"})
 		session.WaitWithDefaultTimeout()
@@ -105,7 +111,6 @@ var _ = Describe("Podman volume ls", func() {
 		session = podmanTest.Podman([]string{"volume", "ls", "--filter", "label=foo=baz"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
 	})
 
 	It("podman ls volume with --filter until flag", func() {
@@ -121,7 +126,6 @@ var _ = Describe("Podman volume ls", func() {
 		session = podmanTest.Podman([]string{"volume", "ls", "--filter", "until=50000"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
 	})
 
 	It("podman volume ls with --filter dangling", func() {
@@ -171,7 +175,6 @@ var _ = Describe("Podman volume ls", func() {
 		session = podmanTest.Podman([]string{"volume", "ls", "--filter", "name=volumex"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
 
 		session = podmanTest.Podman([]string{"volume", "ls", "--filter", "name=volume1"})
 		session.WaitWithDefaultTimeout()

test/e2e/volume_prune_test.go

@@ -68,7 +68,7 @@ var _ = Describe("Podman volume prune", func() {
 		session = podmanTest.Podman([]string{"volume", "ls"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 	})
 
 	It("podman prune volume --filter", func() {
@@ -163,7 +163,7 @@ var _ = Describe("Podman volume prune", func() {
 		session = podmanTest.Podman([]string{"volume", "ls"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 	})
 
 	It("podman volume prune --filter since/after", func() {

test/e2e/volume_rm_test.go

@@ -28,7 +28,7 @@ var _ = Describe("Podman volume rm", func() {
 		session = podmanTest.Podman([]string{"volume", "ls"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 	})
 
 	It("podman volume rm with --force flag", func() {
@@ -48,7 +48,7 @@ var _ = Describe("Podman volume rm", func() {
 		session = podmanTest.Podman([]string{"volume", "ls"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 	})
 
 	It("podman volume remove bogus", func() {
@@ -73,7 +73,7 @@ var _ = Describe("Podman volume rm", func() {
 		session = podmanTest.Podman([]string{"volume", "ls"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 	})
 
 	It("podman volume rm by partial name", func() {
@@ -88,7 +88,7 @@ var _ = Describe("Podman volume rm", func() {
 		session = podmanTest.Podman([]string{"volume", "ls"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(BeEmpty())
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 	})
 
 	It("podman volume rm by nonunique partial name", func() {