Feature: allow running persistent run hooks of all parents

Currently, only one of the persistent pre-runs and post-runs is executed.
It is always the first one found in the parents chain, starting at this command.
Expected behavior is to execute all parents' persistent pre-runs and post-runs.

Dependent projects implemented various workarounds for this:
- manually building persistent hook chains (in every hook).
- applying some kind of monkey-patching on top of Cobra.

This change eliminates the necessity for such workarounds
by allowing to set a global variable EnableTraverseRunHooks.

Tickets:
- spf13#216
- spf13#252

Signed-off-by: Volodymyr Khoroz <volodymyr.khoroz@foundries.io>

cobra.go

@@ -43,9 +43,10 @@ var initializers []func()
 var finalizers []func()
 
 const (
-	defaultPrefixMatching  = false
-	defaultCommandSorting  = true
-	defaultCaseInsensitive = false
+	defaultPrefixMatching   = false
+	defaultCommandSorting   = true
+	defaultCaseInsensitive  = false
+	defaultTraverseRunHooks = false
 )
 
 // EnablePrefixMatching allows setting automatic prefix matching. Automatic prefix matching can be a dangerous thing
@@ -60,6 +61,10 @@ var EnableCommandSorting = defaultCommandSorting
 // EnableCaseInsensitive allows case-insensitive commands names. (case sensitive by default)
 var EnableCaseInsensitive = defaultCaseInsensitive
 
+// EnableTraverseRunHooks executes persistent pre-run and post-run hooks from all parents.
+// By default this is disabled, which means only the first run hook to be found is executed.
+var EnableTraverseRunHooks = defaultTraverseRunHooks
+
 // MousetrapHelpText enables an information splash screen on Windows
 // if the CLI is started from explorer.exe.
 // To disable the mousetrap, just set this variable to blank string ("").

command.go

@@ -934,15 +934,31 @@ func (c *Command) execute(a []string) (err error) {
 		return err
 	}
 
+	parents := make([]*Command, 0, 5)
 	for p := c; p != nil; p = p.Parent() {
+		if EnableTraverseRunHooks {
+			// When EnableTraverseRunHooks is set:
+			// - Execute all persistent pre-runs from the root parent till this command.
+			// - Execute all persistent post-runs from this command till the root parent.
+			parents = append([]*Command{p}, parents...)
+		} else {
+			// Otherwise, execute only the first found persistent hook.
+			parents = append(parents, p)
+		}
+	}
+	for _, p := range parents {
 		if p.PersistentPreRunE != nil {
 			if err := p.PersistentPreRunE(c, argWoFlags); err != nil {
 				return err
 			}
-			break
+			if !EnableTraverseRunHooks {
+				break
+			}
 		} else if p.PersistentPreRun != nil {
 			p.PersistentPreRun(c, argWoFlags)
-			break
+			if !EnableTraverseRunHooks {
+				break
+			}
 		}
 	}
 	if c.PreRunE != nil {
@@ -979,10 +995,14 @@ func (c *Command) execute(a []string) (err error) {
 			if err := p.PersistentPostRunE(c, argWoFlags); err != nil {
 				return err
 			}
-			break
+			if !EnableTraverseRunHooks {
+				break
+			}
 		} else if p.PersistentPostRun != nil {
 			p.PersistentPostRun(c, argWoFlags)
-			break
+			if !EnableTraverseRunHooks {
+				break
+			}
 		}
 	}
 

command_test.go

@@ -1530,57 +1530,73 @@ func TestHooks(t *testing.T) {
 }
 
 func TestPersistentHooks(t *testing.T) {
-	var (
-		parentPersPreArgs  string
-		parentPreArgs      string
-		parentRunArgs      string
-		parentPostArgs     string
-		parentPersPostArgs string
-	)
+	EnableTraverseRunHooks = true
+	testPersistentHooks(t, []string{
+		"parent PersistentPreRun",
+		"child PersistentPreRun",
+		"child PreRun",
+		"child Run",
+		"child PostRun",
+		"child PersistentPostRun",
+		"parent PersistentPostRun",
+	})
 
-	var (
-		childPersPreArgs  string
-		childPreArgs      string
-		childRunArgs      string
-		childPostArgs     string
-		childPersPostArgs string
-	)
+	EnableTraverseRunHooks = false
+	testPersistentHooks(t, []string{
+		"child PersistentPreRun",
+		"child PreRun",
+		"child Run",
+		"child PostRun",
+		"child PersistentPostRun",
+	})
+}
+
+func testPersistentHooks(t *testing.T, expectedHookRunOrder []string) {
+	var hookRunOrder []string
+
+	validateHook := func(args []string, hookName string) {
+		hookRunOrder = append(hookRunOrder, hookName)
+		got := strings.Join(args, " ")
+		if onetwo != got {
+			t.Errorf("Expected %s %q, got %q", hookName, onetwo, got)
+		}
+	}
 
 	parentCmd := &Command{
 		Use: "parent",
 		PersistentPreRun: func(_ *Command, args []string) {
-			parentPersPreArgs = strings.Join(args, " ")
+			validateHook(args, "parent PersistentPreRun")
 		},
 		PreRun: func(_ *Command, args []string) {
-			parentPreArgs = strings.Join(args, " ")
+			validateHook(args, "parent PreRun")
 		},
 		Run: func(_ *Command, args []string) {
-			parentRunArgs = strings.Join(args, " ")
+			validateHook(args, "parent Run")
 		},
 		PostRun: func(_ *Command, args []string) {
-			parentPostArgs = strings.Join(args, " ")
+			validateHook(args, "parent PostRun")
 		},
 		PersistentPostRun: func(_ *Command, args []string) {
-			parentPersPostArgs = strings.Join(args, " ")
+			validateHook(args, "parent PersistentPostRun")
 		},
 	}
 
 	childCmd := &Command{
 		Use: "child",
 		PersistentPreRun: func(_ *Command, args []string) {
-			childPersPreArgs = strings.Join(args, " ")
+			validateHook(args, "child PersistentPreRun")
 		},
 		PreRun: func(_ *Command, args []string) {
-			childPreArgs = strings.Join(args, " ")
+			validateHook(args, "child PreRun")
 		},
 		Run: func(_ *Command, args []string) {
-			childRunArgs = strings.Join(args, " ")
+			validateHook(args, "child Run")
 		},
 		PostRun: func(_ *Command, args []string) {
-			childPostArgs = strings.Join(args, " ")
+			validateHook(args, "child PostRun")
 		},
 		PersistentPostRun: func(_ *Command, args []string) {
-			childPersPostArgs = strings.Join(args, " ")
+			validateHook(args, "child PersistentPostRun")
 		},
 	}
 	parentCmd.AddCommand(childCmd)
@@ -1593,41 +1609,13 @@ func TestPersistentHooks(t *testing.T) {
 		t.Errorf("Unexpected error: %v", err)
 	}
 
-	for _, v := range []struct {
-		name string
-		got  string
-	}{
-		// TODO: currently PersistentPreRun* defined in parent does not
-		// run if the matching child subcommand has PersistentPreRun.
-		// If the behavior changes (https://github.com/spf13/cobra/issues/252)
-		// this test must be fixed.
-		{"parentPersPreArgs", parentPersPreArgs},
-		{"parentPreArgs", parentPreArgs},
-		{"parentRunArgs", parentRunArgs},
-		{"parentPostArgs", parentPostArgs},
-		// TODO: currently PersistentPostRun* defined in parent does not
-		// run if the matching child subcommand has PersistentPostRun.
-		// If the behavior changes (https://github.com/spf13/cobra/issues/252)
-		// this test must be fixed.
-		{"parentPersPostArgs", parentPersPostArgs},
-	} {
-		if v.got != "" {
-			t.Errorf("Expected blank %s, got %q", v.name, v.got)
-		}
-	}
-
-	for _, v := range []struct {
-		name string
-		got  string
-	}{
-		{"childPersPreArgs", childPersPreArgs},
-		{"childPreArgs", childPreArgs},
-		{"childRunArgs", childRunArgs},
-		{"childPostArgs", childPostArgs},
-		{"childPersPostArgs", childPersPostArgs},
-	} {
-		if v.got != onetwo {
-			t.Errorf("Expected %s %q, got %q", v.name, onetwo, v.got)
+	for idx, exp := range expectedHookRunOrder {
+		if len(hookRunOrder) > idx {
+			if act := hookRunOrder[idx]; act != exp {
+				t.Errorf("Expected %q at %d, got %q", exp, idx, act)
+			}
+		} else {
+			t.Errorf("Expected %q at %d, got nothing", exp, idx)
 		}
 	}
 }

site/content/user_guide.md

@@ -687,6 +687,10 @@ Inside subCmd PostRun with args: [arg1 arg2]
 Inside subCmd PersistentPostRun with args: [arg1 arg2]
 ```
 
+By default, only the first persistent hook found in the command chain is executed.
+That is why in the above output, the `rootCmd PersistentPostRun` was not called for a child command.
+Set `EnableTraverseRunHooks` global variable to `true` if you want to execute all parents' persistent hooks.
+
 ## Suggestions when "unknown command" happens
 
 Cobra will print automatic suggestions when "unknown command" errors happen. This allows Cobra to behave similarly to the `git` command when a typo happens. For example: