We were just calling Help() when a user set the --help flag. You could
overwrite how the help subcommand worked with SetHelpFunc, but not now
the --help flag worked.
Today the HelpFunc() seemed to be tailor built for the `help`
subcommand. Which has a rather weird purpose as its `Run` needs to
find the actual command we want to get help about.
Instead make the HelpFunc() for a command be about that command,
rather than having it search for some other command...
This patch enables developers to add one to many template functions that
can be used by custom Usage and Help templates. Here is an example that
is included in the file cobra_test.go as the test function named
TestAddTemplateFunctions:
AddTemplateFunc("t", func() bool { return true })
AddTemplateFuncs(template.FuncMap{
"f": func() bool { return false },
"h": func() string { return "Hello," },
"w": func() string { return "world." }})
const usage = "Hello, world."
c := &Command{}
c.SetUsageTemplate(`{{if t}}{{h}}{{end}}{{if f}}{{h}}{{end}} {{w}}`)
if us := c.UsageString(); us != usage {
t.Errorf("c.UsageString() != \"%s\", is \"%s\"", usage, us)
}
In the above example four functions are added to the template function
map used when the Usage and Help text is generated from the templates
that enable custom logic as well as data injection during template
execution.
```go
package main
import (
"github.com/spf13/cobra"
"github.com/spf13/pflag"
)
func main() {
cmd := &cobra.Command{
Use: "min",
Short: "minimal command",
Run: func(_ *cobra.Command, _ []string) {},
}
pflag.String("oncmdline", "oncmdline", "oncmdline")
cmd.Execute()
}
```
Is a minimal cobra program. When --help is displayed without this patch
you only get:
But with the patch --oncmdline is shows under flags.
This first `cd` to a specified directory, then
lists the subdirectories therein with `_filedir -d`.
This can be used by e.g. `hugo --theme=[Tab][Tab]`, which would
give a list of subdirectories under the `themes` directory.
The template had gotten out of control. It was basically unparsable.
This does a little more work in functions and a little less in the
template. Overall it should be basically the same. It might output the
'additional help topics' in a couple of fewer places, but I doubt people
complain too much...
Calling `cobra-test echo times one two turkey` where `one` and `two` are
valid arguments but `turkey` is not now results in.
Error: invalid argument "turkey" for "cobra-test echo times"
Run 'cobra-test echo times --help' for usage.
Inside Command.Execute() we were checking for pflag.ErrHelp. But
Command.execute() never returns that value. It just complicates the code
and isn't used.
We had lots of quirky if statements like `commandFound.Name() ==
c.Name() && len(stripFlags(args, c)) > 0 && commandFound.Name() !=
args[0]` which embeed all sorts of artifacts which are hard to parse. So
in general, just try to simplify and make stuff readable.
This fixes a problem where if you had a root command and a grand child
with the same name, the parser would break and would not run the
grandchild. The code was special casing if the immediate child had the
same name, but didn't handle grand-children
by now, if someone calls: `program --validflag unknowncommand` the
output will be:
```
Error: unknown command "--validflag"
Run 'program help' for usage.
```
This patch strips out flags so the unknown command is printed:
```
Error: unknown command "unknowncommand"
Run 'program help' for usage.
```
