\NewDocumentEnvironment: existence check without space trimming

[muzimuzhi]

Brief outline of the bug

\(New|Renew|Provide)DocumentEnvironment does the existence check for envname without space trimming, while the actual name of environment to be defined (or redefined) is always space trimmed.

When the user-specified envname consists of leading and/or trailing space(s), it may lead to erroneously silent environment declaration.

Minimal example showing the bug

\RequirePackage{latexbug}       % <--should be always the first line (see CONTRIBUTING)!
\documentclass{article}

\NewDocumentEnvironment {myenv} { } {begin} {end}

\NewDocumentEnvironment {myenv} { } {begin} {end} % errors as expected
\NewDocumentEnvironment { myenv } { } {begin} {end} % !! works, which is wrong

\begin{document}
\end{document}

Log file (required) and possibly PDF file

ltcmd-env-exisistence-check.log

Relevant source lines

latex2e/base/ltcmd.dtx

Lines 5030 to 5047 in 066ad1d

	\cs_new_protected:Npn \NewDocumentEnvironment #1#2#3#4
	{
	\cs_if_exist:cTF {#1}
	{ \msg_error:nnx { cmd } { env-already-defined } {#1} }
	{
	\cs_if_exist:cTF { end #1 }
	{ \msg_error:nnx { cmd } { env-end-already-defined } {#1} }
	{ \@@_declare_env:nnnn {#1} {#2} {#3} {#4} }
	}
	}
	\cs_new_protected:Npn \RenewDocumentEnvironment #1#2#3#4
	{
	\cs_if_exist:cTF {#1}
	{ \@@_declare_env:nnnn {#1} {#2} {#3} {#4} }
	{ \msg_error:nnx { cmd } { env-undefined } {#1} }
	}
	\cs_new_protected:Npn \ProvideDocumentEnvironment #1#2#3#4
	{ \cs_if_exist:cF {#1} { \@@_declare_env:nnnn {#1} {#2} {#3} {#4} } }

latex2e/base/ltcmd.dtx

Lines 629 to 633 in 066ad1d

	\cs_new_protected:Npn \@@_declare_env:nnnn #1#2
	{
	\str_set:Nx \l_@@_environment_str {#1}
	\str_set:Nx \l_@@_environment_str
	{ \tl_trim_spaces:o { \l_@@_environment_str } }

[FrankMittelbach]

guess that classifies as a bug even though I think it is not a high profile bug