Surprisingly, groff supports multiple copy mode escapes at the

beginning of an escape sequence: \, \E, \EE, \EEE, and so on all do
the same outside copy mode, so let them do the same in mandoc(1), too.

This fixes an assertion failure triggered by \EE*X that tb@ found
with afl(1).  The first E was consumed by roff_expand(), but that
function failed to recognize the escape sequence as the expansion
of a user-defined string and handed it over to mandoc_escape(),
which consumed the second E and then died on an assertion because
it is not prepared to handle user-defined strings.  Fix this by
letting *both* functions handle arbitrary numbers of 'E's correctly.

1 files changed, 21 insertions, 0 deletions

diff --git a/regress/roff/esc/E1.out_ascii b/regress/roff/esc/E1.out_ascii
new file mode 100644
index 00000000..1c4dbe14
--- /dev/null
+++ b/regress/roff/esc/E1.out_ascii
@@ -0,0 +1,21 @@
+ESC-E(1)                    General Commands Manual                   ESC-E(1)
+
+NNAAMMEE
+     eesscc--EE - copy-mode escaping of backslashes
+
+DDEESSCCRRIIPPTTIIOONN
+     initial text
+
+     string expansion: myval myval myval myval
+
+     output device: ascii ascii ascii ascii
+
+     numerical expression test: 1 0 1 0
+
+     register: 1 2 3 3
+
+     special character: <= >= << >>
+
+     final text
+
+OpenBSD                         April 13, 2022                         OpenBSD