Remove all instances of named return "err" from Libpod

This was inspired by https://github.com/cri-o/cri-o/pull/3934 and
much of the logic for it is contained there. However, in brief,
a named return called "err" can cause lots of code confusion and
encourages using the wrong err variable in defer statements,
which can make them work incorrectly. Using a separate name which
is not used elsewhere makes it very clear what the defer should
be doing.

As part of this, remove a large number of named returns that were
not used anywhere. Most of them were once needed, but are no
longer necessary after previous refactors (but were accidentally
retained).

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

1 files changed, 6 insertions, 6 deletions

diff --git a/libpod/container_api.go b/libpod/container_api.go
index c7df9d66c..487f75e67 100644
--- a/libpod/container_api.go
+++ b/libpod/container_api.go
@@ -29,7 +29,7 @@ import (
 // Init requires that all dependency containers be started (e.g. pod infra
 // containers). The `recursive` parameter will, if set to true, start these
 // dependency containers before initializing this container.
-func (c *Container) Init(ctx context.Context, recursive bool) (err error) {
+func (c *Container) Init(ctx context.Context, recursive bool) error {
 	span, _ := opentracing.StartSpanFromContext(ctx, "containerInit")
 	span.SetTag("struct", "container")
 	defer span.Finish()
@@ -85,7 +85,7 @@ func (c *Container) Init(ctx context.Context, recursive bool) (err error) {
 // Start requites that all dependency containers (e.g. pod infra containers) be
 // running before being run. The recursive parameter, if set, will start all
 // dependencies before starting this container.
-func (c *Container) Start(ctx context.Context, recursive bool) (err error) {
+func (c *Container) Start(ctx context.Context, recursive bool) error {
 	span, _ := opentracing.StartSpanFromContext(ctx, "containerStart")
 	span.SetTag("struct", "container")
 	defer span.Finish()
@@ -112,7 +112,7 @@ func (c *Container) Start(ctx context.Context, recursive bool) (err error) {
 // Attach call occurs before Start).
 // In overall functionality, it is identical to the Start call, with the added
 // side effect that an attach session will also be started.
-func (c *Container) StartAndAttach(ctx context.Context, streams *define.AttachStreams, keys string, resize <-chan remotecommand.TerminalSize, recursive bool) (attachResChan <-chan error, err error) {
+func (c *Container) StartAndAttach(ctx context.Context, streams *define.AttachStreams, keys string, resize <-chan remotecommand.TerminalSize, recursive bool) (<-chan error, error) {
 	if !c.batched {
 		c.lock.Lock()
 		defer c.lock.Unlock()
@@ -150,7 +150,7 @@ func (c *Container) StartAndAttach(ctx context.Context, streams *define.AttachSt
 }
 
 // RestartWithTimeout restarts a running container and takes a given timeout in uint
-func (c *Container) RestartWithTimeout(ctx context.Context, timeout uint) (err error) {
+func (c *Container) RestartWithTimeout(ctx context.Context, timeout uint) error {
 	if !c.batched {
 		c.lock.Lock()
 		defer c.lock.Unlock()
@@ -160,7 +160,7 @@ func (c *Container) RestartWithTimeout(ctx context.Context, timeout uint) (err e
 		}
 	}
 
-	if err = c.checkDependenciesAndHandleError(); err != nil {
+	if err := c.checkDependenciesAndHandleError(); err != nil {
 		return err
 	}
 
@@ -760,7 +760,7 @@ func (c *Container) Checkpoint(ctx context.Context, options ContainerCheckpointO
 }
 
 // Restore restores a container
-func (c *Container) Restore(ctx context.Context, options ContainerCheckpointOptions) (err error) {
+func (c *Container) Restore(ctx context.Context, options ContainerCheckpointOptions) error {
 	logrus.Debugf("Trying to restore container %s", c.ID())
 	if !c.batched {
 		c.lock.Lock()