compose: fix panic when adding empty header with uppercase letters

Running `:header Hello` causes a panic:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xa09328]

goroutine 1 [running]:
git.sr.ht/~rjarry/aerc/widgets.(*Composer).AddEditor
        git.sr.ht/~rjarry/aerc/widgets/compose.go:1302
git.sr.ht/~rjarry/aerc/commands/compose.Header.Execute
        git.sr.ht/~rjarry/aerc/commands/compose/header.go:83
git.sr.ht/~rjarry/aerc/commands.(*Commands).ExecuteCommand
        git.sr.ht/~rjarry/aerc/commands/commands.go:133
main.execCommand
        git.sr.ht/~rjarry/aerc/main.go:71

This is because addEditor() converts the header name to lowercase before
updating the c.editors map. After this, c.editors[header] (with `header`
containing uppercase letters) returns nil causes a nil pointer access.
This is a side effect of splitting AddEditor into public and private
functions.

focusEditor also converts the argument to lowercase. Fix and simplify
this. Only call focusEditor with whatever the user provided.

Fixes: 11e5390fa0ac ("compose: implement embedded headers in editor")
Reported-by: Koni Marti <koni.marti@gmail.com>
Signed-off-by: Robin Jarry <robin@jarry.cc>
Acked-by: Koni Marti <koni.marti@gmail.com>

0 files changed, 0 insertions, 0 deletions