[latex3-commits] [git/LaTeX3-latex3-latex2e] gh697: Fix patching of commands that contain parameter tokens (4932d3d8)
PhelypeOleinik
phelype.oleinik at latex-project.org
Thu Oct 21 03:53:40 CEST 2021
Repository : https://github.com/latex3/latex2e
On branch : gh697
Link : https://github.com/latex3/latex2e/commit/4932d3d83c9e3f624c8082da869b4ec3ed02c158
>---------------------------------------------------------------
commit 4932d3d83c9e3f624c8082da869b4ec3ed02c158
Author: Phelype Oleinik <phelype.oleinik at latex-project.org>
Date: Wed Oct 20 16:43:17 2021 -0300
Fix patching of commands that contain parameter tokens
Fixes #697
>---------------------------------------------------------------
4932d3d83c9e3f624c8082da869b4ec3ed02c158
base/changes.txt | 5 +
base/doc/ltnews34.tex | 17 ++
base/ltcmdhooks.dtx | 359 ++++++++++++++++++++++++++++-----
base/testfiles-lthooks/github-0697.tlg | 28 ---
4 files changed, 334 insertions(+), 75 deletions(-)
diff --git a/base/changes.txt b/base/changes.txt
index 49326538..c8c36aa9 100644
--- a/base/changes.txt
+++ b/base/changes.txt
@@ -6,6 +6,11 @@ completeness or accuracy and it contains some references to files that
are not part of the distribution.
================================================================================
+2021-10-20 Phelype Oleinik <phelype.oleinik at latex-project.org>
+
+ * ltcmdhooks.dtx (subsubsection{Patching by expansion and redefinition}):
+ Fix patching of commands that contain parameter tokens (gh/697)
+
2021-10-19 Frank Mittelbach <Frank.Mittelbach at latex-project.org>
* ltpara.dtx (subsection{The error messages}):
diff --git a/base/doc/ltnews34.tex b/base/doc/ltnews34.tex
index 86125c31..c949c161 100644
--- a/base/doc/ltnews34.tex
+++ b/base/doc/ltnews34.tex
@@ -320,6 +320,19 @@ preferred.
+\subsection{Fix patching of commands that contain parameter tokens}
+
+In the previous release, \LaTeX's hook mechanism was extended to add
+support for hooking into commands using generic \hook{cmd} hooks
+(see~\cite{34:ltnews33}). The initial version had a bug, in which the
+patching of some commands with a parameter token (normally |#|) in their
+definition would fail with a low-level \TeX{} error. The bug has been
+fixed, and now patching works for those commands as well.
+%
+\githubissue{697}
+
+
+
\subsection{???}
@@ -796,6 +809,10 @@ a \cs{mathopen} has been added to avoid that the anchor affects a following unar
\emph{\LaTeXe{} news 32}.\\
\url{https://latex-project.org/news/latex2e-news/ltnews32.pdf}
+\bibitem{34:ltnews33} \LaTeX{} Project Team:
+ \emph{\LaTeXe{} news 33}.\\
+ \url{https://latex-project.org/news/latex2e-news/ltnews33.pdf}
+
\end{thebibliography}
diff --git a/base/ltcmdhooks.dtx b/base/ltcmdhooks.dtx
index 3f692b2f..26c09ead 100644
--- a/base/ltcmdhooks.dtx
+++ b/base/ltcmdhooks.dtx
@@ -13,8 +13,8 @@
%
%%% From File: ltcmdhooks.dtx
%
-\def\ltcmdhooksversion{v1.0e}
-\def\ltcmdhooksdate{2021/10/14}
+\def\ltcmdhooksversion{v1.0f}
+\def\ltcmdhooksdate{2021/10/20}
%
%
%
@@ -353,19 +353,46 @@
% \end{macro}
%
% \begin{macro}{\l_@@_patch_prefixes_tl}
-% \begin{macro}{\l_@@_patch_param_text_tl}
-% \begin{macro}{\l_@@_patch_replacement_tl}
+% \begin{macro}{\l_@@_param_text_tl}
+% \begin{macro}{\l_@@_replace_text_tl}
% The prefixes and parameters of the definition for the macro being
% patched.
% \begin{macrocode}
\tl_new:N \l_@@_patch_prefixes_tl
-\tl_new:N \l_@@_patch_param_text_tl
-\tl_new:N \l_@@_patch_replacement_tl
+\tl_new:N \l_@@_param_text_tl
+\tl_new:N \l_@@_replace_text_tl
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
+% \begin{macro}{\c_@@_hash_tl}
+% A constant token list that contains two parameter tokens.
+% \begin{macrocode}
+\tl_const:Nn \c_@@_hash_tl { # # }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_exp_not:NN}
+% \begin{macro}{\@@_def_cmd:w}
+% Two temporary macros that change depending on the macro being
+% patched.
+% \begin{macrocode}
+\cs_new_eq:NN \@@_exp_not:NN ?
+\cs_new_eq:NN \@@_def_cmd:w ?
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\q_@@_recursion_tail,\q_@@_recursion_stop}
+% Internal quarks for recursion: they can't appear in any macro being
+% patched.
+% \begin{macrocode}
+\quark_new:N \q_@@_recursion_tail
+\quark_new:N \q_@@_recursion_stop
+% \end{macrocode}
+% \end{macro}
+%
% \begin{macro}{\g_@@_delayed_patches_prop}
% A list containing the patches delayed to |\begin{document}|, so that
% patching is not attempted twice.
@@ -663,13 +690,71 @@
%
%
%
+%
% \begin{macro}{\@@_patch_expand_redefine:NNnn}
+% \begin{macro}{\@@_redefine_with_hooks:Nnnn}
% \begin{macro}[EXP]{\@@_make_prefixes:w}
% Now the real action begins. Here we have in |#1| a boolean
-% indicating if the command has a |[|\ldots|]|-delimited argument, in
-% |#2| the command control sequence, in |#3| the name of the command
-% (note that |#1|${}\ne{}$|\csname#2\endcsname| at this point!), and
-% in |#4| the hook position, either |before| or |after|.
+% indicating if the command has a leading |[|\ldots|]|-delimited
+% argument, in |#2| the command control sequence, in |#3| the name of
+% the command (note that |#1|${}\ne{}$|\csname#2\endcsname| at this
+% point!), and in |#4| the hook position, either |before| or |after|.
+%
+% \changes{v1.0f}{2021/10/20}
+% {Correct patching by expansion+redefinition when the macro
+% contains a parameter tokens (gh/697).}
+% Patching with expansion+redefinition is trickier than it looks like
+% at first glance. Suppose the simple definition:
+% \begin{verbatim}
+% \def\foo#1{#1##2}
+% \end{verbatim}
+% When defined, its \meta{replacement text} will be a token list
+% containing:
+% \begin{quote}
+% \itshape
+% out\_param |1|, mac\_param |#|, character |2|
+% \end{quote}
+%
+% Then, after expanding \cs{foo}|{##1}| (here |##| denotes a single
+% |#|$_6$) we end up with a token list with \textit{out\_param}~|1|
+% replaced:
+% \begin{quote}
+% \itshape
+% mac\_param |#|, character |1|, mac\_param |#|, character |2|
+% \end{quote}
+% that is, the definition would be:
+% \begin{verbatim}
+% \def\foo#1{#1#2}
+% \end{verbatim}
+% which obviously fails, because the original input in the definition
+% was |##| but \TeX{} reduced that to a single parameter token |#|$_6$
+% when carrying out the definition. That leaves no room for a clever
+% solution with (say) \cs{unexpanded}, because anything that would
+% double the second |#|$_6$, would also (incorrectly) double the
+% first, so there's not much to do other than a manual solution.
+%
+% There are three cases we can distinguish to make things hopefully
+% faster on simpler cases:
+% \begin{enumerate}
+% \item a macro with no parameters;
+% \item a macro with no parameter tokens in its definition;
+% \item a macro with parameters \emph{and} parameter tokens.
+% \end{enumerate}
+%
+% The first case is trivial: if the macro has no parameters, we can
+% just use \cs{unexpanded} around it, and if there is a parameter
+% token in it, it is handled correctly (the macro can be treated as a
+% |tl| variable).
+%
+% The second case requires looking at the \meta{replacement text} of
+% the macro to see if it has a parameter token in there. If it does
+% not, then there is no worry, and the macro can be redefined normally
+% (without \cs{unexpanded}).
+%
+% The third case, as usual, is the devious one. Here we'll have to
+% loop through the definition token by token, and double every
+% parameter token, so that this case can be handled like the previous
+% one.
% \begin{macrocode}
\cs_new_protected:Npn \@@_patch_expand_redefine:NNnn #1 #2 #3 #4
{
@@ -689,36 +774,93 @@
% \end{macrocode}
% Now build two token lists:
% \begin{description}
-% \item[\cs{l_@@_patch_param_text_tl}] will contain the
+% \item[\cs{l_@@_param_text_tl}] will contain the
% \meta{parameter text} to be used when redefining the macro. It
% should be identical to the \meta{parameter text} used when
% originally defining that macro.
-% \item[\cs{l_@@_patch_replacement_tl}] will contain braced pairs of
-% |#|$_{12}$\meta{num} to feed to the macro when expanded. This
-% token list as well as the previous will have the first item
+% \item[\cs{l_@@_replace_text_tl}] will contain braced pairs of
+% \cs{c_@@_hash_tl}\meta{num} to feed to the macro when expanded.
+% This token list as well as the previous will have the first item
% surrounded by |[|\ldots|]| in the case of an optional argument.
% \end{description}
+%
+% The use of \cs{c_@@_hash_tl} here is to differentiate actual
+% parameters in the macro from parameter tokens in the original
+% definition of the macro. Later on, \cs{c_@@_hash_tl} is either
+% replaced by actual parameter tokens, or expanded into them.
% \begin{macrocode}
\int_compare:nNnTF { \l_@@_patch_num_args_int } > { \c_zero_int }
{
- \tl_set:Nx \l_@@_patch_param_text_tl
- { \bool_if:NTF #1 { [####1] } { ####1 } }
- \tl_set:Nx \l_@@_patch_replacement_tl
- { \bool_if:NTF #1 { [####1] } { {####1} } }
+% \end{macrocode}
+% We'll first check if the command has any parameter token in its
+% definition (feeding it empty arguments), and set \cs{@@_exp_not:n}
+% accordingly. \cs{@@_exp_not:n} will be used later to either leave
+% \cs{c_@@_hash_tl} or expand it, and also to remember the result of
+% \cs{@@_if_has_hash:nTF} to avoid testing twice (the test can be
+% rather slow).
+% \begin{macrocode}
+ \tl_set:Nx \l_@@_tmpa_tl { \bool_if:NTF #1 { [ ] } { { } } }
\int_step_inline:nnn { 2 } { \l_@@_patch_num_args_int }
+ { \tl_put_right:Nn \l_@@_tmpa_tl { { } } }
+ \exp_args:NNo \exp_args:No \@@_if_has_hash:nTF
+ { \exp_after:wN #2 \l_@@_tmpa_tl }
+ { \cs_set_eq:NN \@@_exp_not:n \exp_not:n }
+ { \cs_set_eq:NN \@@_exp_not:n \use:n }
+ \cs_set_protected:Npn \@@_tmp:w ##1 ##2
{
- \tl_put_right:Nn \l_@@_patch_param_text_tl { ## ####1 }
- \tl_put_right:Nn \l_@@_patch_replacement_tl { { ## ####1 } }
+ ##1 \l_@@_param_text_tl { \use:n ##2 }
+ ##1 \l_@@_replace_text_tl { \@@_exp_not:n {##2} }
}
+% \end{macrocode}
+% Here we'll conditionally add |[|\ldots|]| around the first
+% parameter:
+% \begin{macrocode}
+ \bool_if:NTF #1
+ { \@@_tmp:w \tl_set:Nx { [ \c_@@_hash_tl 1 ] } }
+ { \@@_tmp:w \tl_set:Nx { { \c_@@_hash_tl 1 } } }
+% \end{macrocode}
+% Then, for every parameter from the second, just add it normally:
+% \begin{macrocode}
+ \int_step_inline:nnn { 2 } { \l_@@_patch_num_args_int }
+ { \@@_tmp:w \tl_put_right:Nx { { \c_@@_hash_tl ##1 } } }
+% \end{macrocode}
+% Now, if the command has any parameter token in its definition
+% (then \cs{@@_exp_not:n} is \cs{exp_not:n}), call
+% \cs{@@_double_hashes:n} to double them, and replace every
+% \cs{c_@@_hash_tl} by |#|:
+% \begin{macrocode}
+ \tl_set:Nx \l_@@_replace_text_tl
+ { \exp_not:N #2 \exp_not:V \l_@@_replace_text_tl }
+ \tl_set:Nx \l_@@_replace_text_tl
+ {
+ \token_if_eq_meaning:NNTF \@@_exp_not:n \exp_not:n
+ { \exp_args:NNV \exp_args:No \@@_double_hashes:n }
+ { \exp_args:NV \exp_not:o }
+ \l_@@_replace_text_tl
+ }
+% \end{macrocode}
+% And now, set a few auxiliaries for the case that the macro has
+% parameters, so it won't be passed through \cs{unexpanded} (twice):
+% \begin{macrocode}
+ \cs_set_eq:NN \@@_def_cmd:w \tex_gdef:D
+ \cs_set_eq:NN \@@_exp_not:NN \prg_do_nothing:
}
{
- \tl_clear:N \l_@@_patch_param_text_tl
- \tl_clear:N \l_@@_patch_replacement_tl
+% \end{macrocode}
+% In the case the macro has no parameters, we'll treat it as a token
+% list and things are much simpler (expansion control looks a bit
+% complicated, but it's just a pair of \cs{exp_not:N} preventing
+% another \cs{exp_not:n} from expanding):
+% \begin{macrocode}
+ \tl_clear:N \l_@@_param_text_tl
+ \tl_set_eq:NN \l_@@_replace_text_tl #2
+ \cs_set_eq:NN \@@_def_cmd:w \tex_xdef:D
+ \cs_set:Npn \@@_exp_not:NN ##1 { \exp_not:N ##1 \exp_not:N }
}
% \end{macrocode}
-% Finally, before redefining, we need to also get the prefixes used
-% when defining the command. Here we ensure that the \tn{escapechar}
-% is printable, otherwise a macro defined with prefixes
+% Before redefining, we need to also get the prefixes used when
+% defining the command. Here we ensure that the \tn{escapechar} is
+% printable, otherwise a macro defined with prefixes
% |\protected \long| will have it \tn{meaning} printed as
% |protectedlong|, making life unnecessarily complicated. Here the
% \tn{escapechar} is changed to |/|, then we loop between pairs of
@@ -733,34 +875,44 @@
{ \exp_not:N \@@_make_prefixes:w \cs_prefix_spec:N #2 / / }
}
% \end{macrocode}
+% Finally, call \cs{@@_redefine_with_hooks:Nnnn} with the macro being
+% redefined in |#1|, then \cs{UseHook}|{cmd/<name>/before}| in |#2| or
+% \cs{UseHook}|{cmd/<name>/after}| in |#3| (one is always empty), and
+% in |#4| the \meta{replacement text} of the macro.
+% \begin{macrocode}
+ \use:x
+ {
+ \@@_redefine_with_hooks:Nnnn \exp_not:N #2
+ \str_if_eq:nnTF {#4} { after }
+ { \use_ii_i:nn }
+ { \use:nn }
+ { { \@@_exp_not:NN \exp_not:N \UseHook { cmd / #3 / #4 } } }
+ { { } }
+ { \@@_exp_not:NN \exp_not:V \l_@@_replace_text_tl }
+ }
+ }
+% \end{macrocode}
+%
% Now that all the needed tools are ready, without further ado we'll
-% redefine the command |#2|. The definition uses the prefixes
-% gathered in \cs{l_@@_patch_prefixes_tl}, a primitive \cs{tex_def:D}
-% to avoid adding extra prefixes, and the \meta{parameter text} from
-% \cs{l_@@_patch_param_text_tl}.
+% redefine the command. The definition uses the prefixes gathered in
+% \cs{l_@@_patch_prefixes_tl}, a primitive \cs{@@_def_cmd:w} (which is
+% \cs{tex_gdef:D} or \cs{tex_xdef:D}) to avoid adding extra prefixes,
+% and the \meta{parameter text} from \cs{l_@@_param_text_tl}.
%
-% Then finally, in the body of the definition, we insert
-% \hook{cmd/\#3/before} if |#4| is |before|, the code of the
-% command expanded once grabbing the parameters in
-% \cs{l_@@_patch_replacement_tl}, and \hook{cmd/\#3/after} if |#4| is
-% |after|.
+% Then finally, in the body of the definition, we insert |#2|, which
+% is \hook{cmd/\#1/before} or empty, |#4| which is the
+% \meta{replacement text}, and |#3| which is \hook{cmd/\#1/after} or
+% empty.
%
% \changes{v1.0e}{2021/09/28}
% {Make patching of commands a global operation (gh/674)}
% \begin{macrocode}
- \use:x
- {
- \l_@@_patch_prefixes_tl \tex_gdef:D
- \exp_not:N #2 \exp_not:V \l_@@_patch_param_text_tl
- {
- \str_if_eq:nnT {#4} { before }
- { \exp_not:N \UseHook { cmd / #3 / #4 } }
- \exp_args:No \exp_not:o
- { \exp_after:wN #2 \l_@@_patch_replacement_tl }
- \str_if_eq:nnT {#4} { after }
- { \exp_not:N \UseHook { cmd / #3 / #4 } }
- }
- }
+\cs_new_protected:Npn \@@_redefine_with_hooks:Nnnn #1 #2 #3 #4
+ {
+ \l_@@_patch_prefixes_tl
+ \exp_after:wN \@@_def_cmd:w
+ \exp_after:wN #1 \l_@@_param_text_tl
+ { #2 #4 #3 }
}
% \end{macrocode}
%
@@ -779,9 +931,122 @@
% \end{macrocode}
% \end{macro}
% \end{macro}
+% \end{macro}
+%
+%
+% Here are some auxiliaries for the contraption above.
+%
+% \begin{macro}[pTF]{\@@_if_has_hash:n}
+% \begin{macro}{\@@_if_has_hash:w,\@@_if_has_hash_check:w}
+% \cs{@@_if_has_hash:nTF} searches the token list |#1| for a catcode~6
+% token, and if any is found, it returns |true|, and |false|
+% otherwise. The searching doesn't care about preserving groups or
+% spaces: we can ignore those safely (braces are removed) so that
+% searching is as fast as possible.
+% \begin{macrocode}
+\prg_new_conditional:Npnn \@@_if_has_hash:n #1 { TF }
+ { \@@_if_has_hash:w #1 ## \s_@@_mark }
+\cs_new:Npn \@@_if_has_hash:w #1
+ {
+ \tl_if_single_token:nTF {#1}
+ {
+ \token_if_eq_catcode:NNTF ## #1
+ { \@@_if_has_hash_check:w }
+ { \@@_if_has_hash:w }
+ }
+ { \@@_if_has_hash:w #1 }
+ }
+\cs_new:Npn \@@_if_has_hash_check:w #1 \s_@@_mark
+ { \tl_if_empty:nTF {#1} { \prg_return_false: } { \prg_return_true: } }
+% \end{macrocode}
+% \end{macro}
%
%
+% \begin{macro}[rEXP]{\@@_double_hashes:n}
+% \begin{macro}[rEXP]{
+% \@@_double_hashes:w,
+% \@@_double_hashes_output:N,
+% \@@_double_hashes_stop:w,
+% \@@_double_hashes_group:n,
+% \@@_double_hashes_space:w,
+% }
+% \cs{@@_double_hashes:n} loops through the token list |#1| and
+% duplicates any catcode~6 token, and expands tokens \cs{ifx}-equal to
+% \cs{c_@@_hash_tl}, and leaves all other tokens \cs{notexpanded} with
+% \cs{exp_not:N}. Unfortunately pairs of explicit catcode~1 and
+% catcode~2 character tokens are normalised to |{|$_1$ and |}|$_1$
+% because it's not feasible to expandably detect the character code
+% (\emph{maybe} it could be done using something along the lines of
+% \url{https://tex.stackexchange.com/a/527538}, but it's far too much
+% work for close to zero benefit).
+%
+% \cs{@@_double_hashes:w} is the tail-recursive loop macro, that tests
+% which of the three types of item is in the head of the token list.
+% \begin{macrocode}
+\cs_new:Npn \@@_double_hashes:n #1
+ { \@@_double_hashes:w #1 \q_@@_recursion_tail \q_@@_recursion_stop }
+\cs_new:Npn \@@_double_hashes:w #1 \q_@@_recursion_stop
+ {
+ \tl_if_head_is_N_type:nTF {#1}
+ { \@@_double_hashes_output:N }
+ {
+ \tl_if_head_is_group:nTF {#1}
+ { \@@_double_hashes_group:n }
+ { \@@_double_hashes_space:w }
+ }
+ #1 \q_@@_recursion_stop
+ }
+% \end{macrocode}
%
+% \cs{@@_double_hashes_output:N} checks for the end of the token list,
+% then checks if the token is \cs{c_@@_hash_tl}, and if so just leaves
+% it.
+% \begin{macrocode}
+\cs_new:Npn \@@_double_hashes_output:N #1
+ {
+ \if_meaning:w \q_@@_recursion_tail #1
+ \@@_double_hashes_stop:w
+ \fi:
+ \if_meaning:w \c_@@_hash_tl #1
+% \end{macrocode}
+% (this \cs{use_i:nnnn} uses \cs{fi:} and consumes \cs{use:n}, the
+% whole \cs{if_catcode:w} block, and the \cs{exp_not:N}, leaving just
+% |#1| which is \cs{c_@@_hash_tl}.)
+% \begin{macrocode}
+ \use_i:nnnn
+ \fi:
+ \use:n
+ {
+% \end{macrocode}
+% If |#1| is not \cs{c_@@_hash_tl}, then check if its catcode is~6,
+% and if so, leave it doubled in \cs{exp_not:n} and consume the
+% following |\exp_not:N #1|.
+% \begin{macrocode}
+ \if_catcode:w ## \exp_not:N #1
+ \exp_after:wN \use_ii:nnnn
+ \fi:
+ \use_none:n
+ { \exp_not:n { #1 #1 } }
+ }
+% \end{macrocode}
+% If both previous tests returned |false|, then leave the token
+% unexpanded and resume the loop.
+% \begin{macrocode}
+ \exp_not:N #1
+ \@@_double_hashes:w
+ }
+\cs_new:Npn \@@_double_hashes_stop:w #1 \q_@@_recursion_stop { \fi: }
+% \end{macrocode}
+%
+% Dealing with spaces and grouped tokens is trivial:
+% \begin{macrocode}
+\cs_new:Npn \@@_double_hashes_group:n #1
+ { { \@@_double_hashes:n {#1} } \@@_double_hashes:w }
+\exp_last_unbraced:NNo
+\cs_new:Npn \@@_double_hashes_space:w \c_space_tl
+ { ~ \@@_double_hashes:w }
+% \end{macrocode}
+% \end{macro}
%
%
%
diff --git a/base/testfiles-lthooks/github-0697.tlg b/base/testfiles-lthooks/github-0697.tlg
index acc3d61b..addc7b80 100644
--- a/base/testfiles-lthooks/github-0697.tlg
+++ b/base/testfiles-lthooks/github-0697.tlg
@@ -1,33 +1,5 @@
This is a generated file for the LaTeX2e validation system.
Don't change this file in any respect.
-! Illegal parameter number in definition of \fooA .
-<to be read again>
- }
-l. ...\__hook_cmd_begindocument_code:
-You meant to type ## instead of #, right?
-Or maybe a } was forgotten somewhere earlier, and things
-are all screwed up? I'm going to assume that you meant ##.
-! Illegal parameter number in definition of \fooC .
-<to be read again>
- 2
-l. ...\__hook_cmd_begindocument_code:
-You meant to type ## instead of #, right?
-Or maybe a } was forgotten somewhere earlier, and things
-are all screwed up? I'm going to assume that you meant ##.
-! Illegal parameter number in definition of \barA .
-<to be read again>
- 2
-l. ...\__hook_cmd_begindocument_code:
-You meant to type ## instead of #, right?
-Or maybe a } was forgotten somewhere earlier, and things
-are all screwed up? I'm going to assume that you meant ##.
-! Illegal parameter number in definition of \barB .
-<to be read again>
- 2
-l. ...\__hook_cmd_begindocument_code:
-You meant to type ## instead of #, right?
-Or maybe a } was forgotten somewhere earlier, and things
-are all screwed up? I'm going to assume that you meant ##.
fooA
##
fooB
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