feat(comp): Dynamic completion for --output flag

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

cmd/helm/flags.go

@@ -52,6 +52,8 @@ func addChartPathOptionsFlags(f *pflag.FlagSet, c *action.ChartPathOptions) {
 // value to the given format pointer
 func bindOutputFlag(cmd *cobra.Command, varRef *output.Format) {
 	cmd.Flags().VarP(newOutputValue(output.Table, varRef), outputFlag, "o", fmt.Sprintf("prints the output in the specified format. Allowed values: %s, %s, %s", output.Table, output.JSON, output.YAML))
+	// Setup shell completion for the flag
+	cmd.MarkFlagCustom(outputFlag, "__helm_output_options")
 }
 
 type outputValue output.Format

cmd/helm/root.go

@@ -89,6 +89,12 @@ __helm_get_namespaces()
     fi
 }
 
+__helm_output_options()
+{
+    __helm_debug "${FUNCNAME[0]}: c is $c words[c] is ${words[c]}"
+    COMPREPLY+=( $( compgen -W "table json yaml" -- "$cur" ) )
+}
+
 __helm_binary_name()
 {
     local helm_binary