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File 2335-Add-shell-shortcut-for-recompiling-existing-modules.patch of Package erlang (Revision 3aaa84d7d540d57752db68644dc4a4df)

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From 0eb45e21d406539caaad98bfc1740f9a11e32565 Mon Sep 17 00:00:00 2001
From: Richard Carlsson <richardc@klarna.com>
Date: Tue, 6 Dec 2016 12:14:18 +0100
Subject: [PATCH 5/8] Add shell shortcut for recompiling existing modules

This extends the shell function c/1 and c/2 so that if the argument is a
module name instead of a file name, it automatically locates the .beam file
and the corresponding source file, and then recompiles the module using the
same compiler options (plus any options passed to c/2). If compilation
fails, the old beam file is preserved. Also adds c(Mod, Opts, Filter),
where the Filter argument allows you to remove old compiler options before
the new options are added.
---
 lib/stdlib/doc/src/c.xml         |  26 +++-
 lib/stdlib/doc/src/shell.xml     |  10 +-
 lib/stdlib/src/c.erl             | 254 ++++++++++++++++++++++++++++++++++-----
 lib/stdlib/src/shell_default.erl |   3 +-
 lib/stdlib/test/shell_SUITE.erl  |   2 +-
 5 files changed, 252 insertions(+), 43 deletions(-)

diff --git a/lib/stdlib/doc/src/c.xml b/lib/stdlib/doc/src/c.xml
index 55a77d1bc..766669918 100644
--- a/lib/stdlib/doc/src/c.xml
+++ b/lib/stdlib/doc/src/c.xml
@@ -52,13 +52,27 @@
 <func>
 <name name="c" arity="1"/>
 <name name="c" arity="2"/>
- <fsummary>Compile and load code in a file.</fsummary>
+ <name name="c" arity="3"/>
+ <fsummary>Compile and load a file or module.</fsummary>
 <desc>
- Compiles and then purges and loads the code for a file.
- <c><anno>Options</anno></c> defaults to <c>[]</c>. Compilation is
- equivalent to:
- <code type="none">
-compile:file(<anno>File</anno>, <anno>Options</anno> ++ [report_errors, report_warnings])</code>
+ Compiles and then purges and loads the code for a module.
+ <c><anno>Module</anno></c> can be either a module name or a source
+ file path, with or without <c>.erl</c> extension.
+ <c><anno>Options</anno></c> defaults to <c>[]</c>.
+ If <c><anno>Module</anno></c> is an atom and is not the path of a
+ source file, then the code path is searched to locate the object
+ file for the module and extract its original compiler options and
+ source path. If the source file is not found in the original
+ location, <seealso
+ marker="filelib#find_source/1"><c>filelib:find_source/1</c></seealso>
+ is used to search for it relative to the directory of the object
+ file.
+ The source file is compiled with the the original
+ options appended to the given <c><anno>Options</anno></c>, the
+ output replacing the old object file if and only if compilation
+ succeeds. A function <c><anno>Filter</anno></c> can be specified
+ for removing elements from from the original compiler options
+ before the new options are added.
 Notice that purging the code means that any processes
 lingering in old code for the module are killed without
 warning. For more information, see <c>code/3</c>.
diff --git a/lib/stdlib/doc/src/shell.xml b/lib/stdlib/doc/src/shell.xml
index d6e8036d4..f52bc39de 100644
--- a/lib/stdlib/doc/src/shell.xml
+++ b/lib/stdlib/doc/src/shell.xml
@@ -165,12 +165,12 @@
 <item>
 Evaluates <c>shell_default:help()</c>.
 </item>
- <tag><c>c(File)</c></tag>
+ <tag><c>c(Mod)</c></tag>
 <item>
- Evaluates <c>shell_default:c(File)</c>. This compiles
- and loads code in <c>File</c> and purges old versions of
- code, if necessary. Assumes that the file and module names
- are the same.
+ Evaluates <c>shell_default:c(Mod)</c>. This compiles and
+ loads the module <c>Mod</c> and purges old versions of the
+ code, if necessary. <c>Mod</c> can be either a module name or a
+ a source file path, with or without <c>.erl</c> extension.
 </item>
 <tag><c>catch_exception(Bool)</c></tag>
 <item>
diff --git a/lib/stdlib/src/c.erl b/lib/stdlib/src/c.erl
index d36630214..d3f9a9c7a 100644
--- a/lib/stdlib/src/c.erl
+++ b/lib/stdlib/src/c.erl
@@ -23,7 +23,7 @@
 
 %% Avoid warning for local function error/2 clashing with autoimported BIF.
 -compile({no_auto_import,[error/2]}).
--export([help/0,lc/1,c/1,c/2,nc/1,nc/2, nl/1,l/1,i/0,i/1,ni/0,
+-export([help/0,lc/1,c/1,c/2,c/3,nc/1,nc/2, nl/1,l/1,i/0,i/1,ni/0,
 y/1, y/2,
 	 lc_batch/0, lc_batch/1,
 	 i/3,pid/3,m/0,m/1,mm/0,lm/0,
@@ -44,7 +44,7 @@
 
 help() ->
 io:put_chars(<<"bt(Pid) -- stack backtrace for a process\n"
-		 "c(File) -- compile and load code in <File>\n"
+		 "c(Mod) -- compile and load module or file <Mod>\n"
 		 "cd(Dir) -- change working directory\n"
 		 "flush() -- flush any messages sent to the shell\n"
 		 "help() -- help info\n"
@@ -72,32 +72,222 @@ help() ->
 		 "xm(M) -- cross reference check a module\n"
 		 "y(File) -- generate a Yecc parser\n">>).
 
-%% c(FileName)
-%% Compile a file/module.
+%% c(Module)
+%% Compile a module/file.
 
--spec c(File) -> {'ok', Module} | 'error' when
- File :: file:name(),
- Module :: module().
+-spec c(Module) -> {'ok', ModuleName} | 'error' when
+ Module :: file:name(),
+ ModuleName :: module().
 
-c(File) -> c(File, []).
+c(Module) -> c(Module, []).
 
--spec c(File, Options) -> {'ok', Module} | 'error' when
- File :: file:name(),
+-spec c(Module, Options) -> {'ok', ModuleName} | 'error' when
+ Module :: file:name(),
 Options :: [compile:option()],
- Module :: module().
+ ModuleName :: module().
+
+c(Module, Opts) when is_atom(Module) ->
+ %% either a module name or a source file name (possibly without
+ %% suffix); if such a source file exists, it is used to compile from
+ %% scratch with the given options, otherwise look for an object file
+ Suffix = case filename:extension(Module) of
+ "" -> src_suffix(Opts);
+ S -> S
+ end,
+ SrcFile = filename:rootname(Module, Suffix) ++ Suffix,
+ case filelib:is_file(SrcFile) of
+ true ->
+ compile_and_load(SrcFile, Opts);
+ false ->
+ c(Module, Opts, fun (_) -> true end)
+ end;
+c(Module, Opts) ->
+ %% we never interpret a string as a module name, only as a file
+ compile_and_load(Module, Opts).
+
+%% This tries to find an existing object file and use its compile_info and
+%% source path to recompile the module, overwriting the old object file.
+%% The Filter parameter is applied to the old compile options
+
+-spec c(Module, Options, Filter) -> {'ok', ModuleName} | 'error' when
+ Module :: atom(),
+ Options :: [compile:option()],
+ Filter :: fun ((compile:option()) -> boolean()),
+ ModuleName :: module().
+
+c(Module, Options, Filter) when is_atom(Module) ->
+ case find_beam(Module) of
+ BeamFile when is_list(BeamFile) ->
+ c(Module, Options, Filter, BeamFile);
+ Error ->
+ {error, Error}
+ end.
+
+c(Module, Options, Filter, BeamFile) ->
+ case compile_info(Module, BeamFile) of
+ Info when is_list(Info) ->
+ case find_source(BeamFile, Info) of
+ SrcFile when is_list(SrcFile) ->
+ c(SrcFile, Options, Filter, BeamFile, Info);
+ Error ->
+ Error
+ end;
+ Error ->
+ Error
+ end.
+
+c(SrcFile, NewOpts, Filter, BeamFile, Info) ->
+ %% Filter old options; also remove options that will be replaced.
+ %% Write new beam over old beam unless other outdir is specified.
+ F = fun (Opt) -> not is_outdir_opt(Opt) andalso Filter(Opt) end,
+ Options = (NewOpts ++ [{outdir,filename:dirname(BeamFile)}]
+ ++ lists:filter(F, old_options(Info))),
+ format("Recompiling ~s\n", [SrcFile]),
+ safe_recompile(SrcFile, Options, BeamFile).
+
+old_options(Info) ->
+ case lists:keyfind(options, 1, Info) of
+ {options, Opts} -> Opts;
+ false -> []
+ end.
+
+%% prefer the source path in the compile info if the file exists,
+%% otherwise do a standard source search relative to the beam file
+find_source(BeamFile, Info) ->
+ case lists:keyfind(source, 1, Info) of
+ {source, SrcFile} ->
+ case filelib:is_file(SrcFile) of
+ true -> SrcFile;
+ false -> find_source(BeamFile)
+ end;
+ _ ->
+ find_source(BeamFile)
+ end.
+
+find_source(BeamFile) ->
+ case filelib:find_source(BeamFile) of
+ {ok, SrcFile} -> SrcFile;
+ _ -> {error, no_source}
+ end.
 
-c(File, Opts0) when is_list(Opts0) ->
- Opts = [report_errors,report_warnings|Opts0],
+%% find the beam file for a module, preferring the path reported by code:which()
+%% if it still exists, or otherwise by searching the code path
+find_beam(Module) when is_atom(Module) ->
+ case code:which(Module) of
+ Beam when is_list(Beam), Beam =/= "" ->
+ case erlang:module_loaded(Module) of
+ false ->
+ Beam; % code:which/1 found this in the path
+ true ->
+ case filelib:is_file(Beam) of
+ true -> Beam;
+ false -> find_beam_1(Module) % file moved?
+ end
+ end;
+ Other when Other =:= ""; Other =:= cover_compiled ->
+ %% module is loaded but not compiled directly from source
+ find_beam_1(Module);
+ Error ->
+ Error
+ end.
+
+find_beam_1(Module) ->
+ File = atom_to_list(Module) ++ code:objfile_extension(),
+ case code:where_is_file(File) of
+ Beam when is_list(Beam) ->
+ Beam;
+ Error ->
+ Error
+ end.
+
+%% get the compile_info for a module
+%% -will report the info for the module in memory, if loaded
+%% -will try to find and examine the beam file if not in memory
+%% -will not cause a module to become loaded by accident
+compile_info(Module, Beam) when is_atom(Module) ->
+ case erlang:module_loaded(Module) of
+ true ->
+ %% getting the compile info for a loaded module should normally
+ %% work, but return an empty info list if it fails
+ try erlang:get_module_info(Module, compile)
+ catch _:_ -> []
+ end;
+ false ->
+ case beam_lib:chunks(Beam, [compile_info]) of
+ {ok, {_Module, [{compile_info, Info}]}} ->
+ Info;
+ Error ->
+ Error
+ end
+ end.
+
+%% compile module, backing up any existing target file and restoring the
+%% old version if compilation fails (this should only be used when we have
+%% an old beam file that we want to preserve)
+safe_recompile(File, Options, BeamFile) ->
+ %% Note that it's possible that because of options such as 'to_asm',
+ %% the compiler might not actually write a new beam file at all
+ Backup = BeamFile ++ ".bak",
+ case file:rename(BeamFile, Backup) of
+ Status when Status =:= ok; Status =:= {error,enoent} ->
+ case compile_and_load(File, Options) of
+ {ok, _} = Result ->
+ _ = if Status =:= ok -> file:delete(Backup);
+ true -> ok
+ end,
+ Result;
+ Error ->
+ _ = if Status =:= ok -> file:rename(Backup, BeamFile);
+ true -> ok
+ end,
+ Error
+ end;
+ Error ->
+ Error
+ end.
+
+%% Compile the file and load the resulting object code (if any).
+%% Automatically ensures that there is an outdir option, by default the
+%% directory of File, and that a 'from' option will be passed to match the
+%% actual source suffix if needed (unless already specified).
+compile_and_load(File, Opts0) when is_list(Opts0) ->
+ Opts = [report_errors, report_warnings
+ | ensure_from(filename:extension(File),
+ ensure_outdir(filename:dirname(File), Opts0))],
 case compile:file(File, Opts) of
 	{ok,Mod} ->				%Listing file.
-	 machine_load(Mod, File, Opts);
+	 purge_and_load(Mod, File, Opts);
 	{ok,Mod,_Ws} ->				%Warnings maybe turned on.
-	 machine_load(Mod, File, Opts);
+	 purge_and_load(Mod, File, Opts);
 	Other ->				%Errors go here
 	 Other
 end;
-c(File, Opt) -> 
- c(File, [Opt]).
+compile_and_load(File, Opt) ->
+ compile_and_load(File, [Opt]).
+
+ensure_from(Suffix, Opts0) ->
+ case lists:partition(fun is_from_opt/1, Opts0++from_opt(Suffix)) of
+ {[Opt|_], Opts} -> [Opt | Opts];
+ {[], Opts} -> Opts
+ end.
+
+ensure_outdir(Dir, Opts0) ->
+ {[Opt|_], Opts} = lists:partition(fun is_outdir_opt/1,
+ Opts0++[{outdir,Dir}]),
+ [Opt | Opts].
+
+is_outdir_opt({outdir, _}) -> true;
+is_outdir_opt(_) -> false.
+
+is_from_opt(from_core) -> true;
+is_from_opt(from_asm) -> true;
+is_from_opt(from_beam) -> true;
+is_from_opt(_) -> false.
+
+from_opt(".core") -> [from_core];
+from_opt(".S") -> [from_asm];
+from_opt(".beam") -> [from_beam];
+from_opt(_) -> [].
 
 %%% Obtain the 'outdir' option from the argument. Return "." if no
 %%% such option was given.
@@ -113,18 +303,29 @@ outdir([Opt|Rest]) ->
 	 outdir(Rest)
 end.
 
+%% mimic how suffix is selected in compile:file().
+src_suffix([from_core|_]) -> ".core";
+src_suffix([from_asm|_]) -> ".S";
+src_suffix([from_beam|_]) -> ".beam";
+src_suffix([_|Opts]) -> src_suffix(Opts);
+src_suffix([]) -> ".erl".
+
 %%% We have compiled File with options Opts. Find out where the
-%%% output file went to, and load it.
-machine_load(Mod, File, Opts) ->
+%%% output file went and load it, purging any old version.
+purge_and_load(Mod, File, Opts) ->
 Dir = outdir(Opts),
- File2 = filename:join(Dir, filename:basename(File, ".erl")),
+ Base = filename:basename(File, src_suffix(Opts)),
+ OutFile = filename:join(Dir, Base),
 case compile:output_generated(Opts) of
 	true ->
-	 Base = atom_to_list(Mod),
-	 case filename:basename(File, ".erl") of
+	 case atom_to_list(Mod) of
 		Base ->
 		 code:purge(Mod),
-		 check_load(code:load_abs(File2,Mod), Mod);
+ %% Note that load_abs() adds the object file suffix
+		 case code:load_abs(OutFile, Mod) of
+ {error, _R}=Error -> Error;
+ _ -> {ok, Mod}
+ end;
 		_OtherMod ->
 		 format("** Module name '~p' does not match file name '~tp' **~n",
 			 [Mod,File]),
@@ -135,13 +336,6 @@ machine_load(Mod, File, Opts) ->
 	 ok
 end.
 
-%%% This function previously warned if the loaded module was
-%%% loaded from some other place than current directory.
-%%% Now, loading from other than current directory is supposed to work.
-%%% so this function does nothing special.
-check_load({error, _R} = Error, _) -> Error;
-check_load(_, Mod) -> {ok, Mod}.
-
 %% Compile a list of modules
 %% enables the nice unix shell cmd
 %% erl -s c lc f1 f2 f3 @d c1=v1 @c2 @i IDir @o ODir -s erlang halt
diff --git a/lib/stdlib/src/shell_default.erl b/lib/stdlib/src/shell_default.erl
index cd63ab28b..a0c1d9851 100644
--- a/lib/stdlib/src/shell_default.erl
+++ b/lib/stdlib/src/shell_default.erl
@@ -23,7 +23,7 @@
 
 -module(shell_default).
 
--export([help/0,lc/1,c/1,c/2,nc/1,nl/1,l/1,i/0,pid/3,i/3,m/0,m/1,lm/0,mm/0,
+-export([help/0,lc/1,c/1,c/2,c/3,nc/1,nl/1,l/1,i/0,pid/3,i/3,m/0,m/1,lm/0,mm/0,
 memory/0,memory/1,uptime/0,
 	 erlangrc/1,bi/1, regs/0, flush/0,pwd/0,ls/0,ls/1,cd/1, 
 y/1, y/2,
@@ -72,6 +72,7 @@ bi(I) 		-> c:bi(I).
 bt(Pid)		-> c:bt(Pid).
 c(File) 	-> c:c(File).
 c(File, Opt) -> c:c(File, Opt).
+c(File, Opt, Filter) -> c:c(File, Opt, Filter).
 cd(D) -> c:cd(D).
 erlangrc(X) 	-> c:erlangrc(X).
 flush() -> c:flush().
diff --git a/lib/stdlib/test/shell_SUITE.erl b/lib/stdlib/test/shell_SUITE.erl
index 15ccdea28..4864bc3d7 100644
--- a/lib/stdlib/test/shell_SUITE.erl
+++ b/lib/stdlib/test/shell_SUITE.erl
@@ -282,7 +282,7 @@ restricted_local(Config) when is_list(Config) ->
 	comm_err(<<"begin F=fun() -> hello end, foo(F) end.">>),
 "exception error: undefined shell command banan/1" =
 	comm_err(<<"begin F=fun() -> hello end, banan(F) end.">>),
- "{error,"++_ = t(<<"begin F=fun() -> hello end, c(F) end.">>),
+ "Recompiling "++_ = t(<<"c(shell_SUITE).">>),
 "exception exit: restricted shell does not allow l(" ++ _ =
 	comm_err(<<"begin F=fun() -> hello end, l(F) end.">>),
 "exception error: variable 'F' is unbound" =
-- 
2.11.1

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File 2335-Add-shell-shortcut-for-recompiling-existing-modules.patch of Package erlang (Revision 3aaa84d7d540d57752db68644dc4a4df)

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