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Added check for sed return code, switched to bash and also properly i… #1593

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d6d99e5
Added check for sed return code, switched to bash and also properly i…
Nov 11, 2019
aa27b81
Added space
Nov 11, 2019
18ac8ce
Added set -e at suggestion of @FloEdelmann
Nov 14, 2019
0516f69
Removed conditional that was obsoleted by sed -e
Nov 14, 2019
b01e907
Merge branch 'master' into convert-readme-newlines
peternewman Jan 27, 2020
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9 changes: 6 additions & 3 deletions plugins/convert_README_to_header.sh
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Original file line number Diff line number Diff line change
@@ -1,9 +1,11 @@
#!/bin/sh
#!/bin/bash
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@peternewman peternewman Nov 11, 2019

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As per the discussion in the issue, this needs reverting as it won't work on FreeBSD:
https://www.freebsd.org/doc/en_US.ISO8859-1/articles/linux-users/shells.html

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@Keeper-of-the-Keys Keeper-of-the-Keys Nov 11, 2019

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bash is not the default shell but it is available, whether installed or not is a different story but we can and should make it a dependency.

grep -R '#! /bin/bash' . | wc -l returns 41 on the OLA source directory so saying we depend on bash is reasonable if not necessary.

In addition to that /bin/sh causes a crapshoot of unpredictable shell interpreters where each distro is running it through whatever sh-like solution they happen to like and stuff works or doesn't work while bash is bash is bash (except maybe for version stuff but unless we use some cutting edge bash feature we're not likely to run into that).

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@Keeper-of-the-Keys Keeper-of-the-Keys Nov 11, 2019

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And grep -R '#!/bin/bash' . | wc -l returns 9

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@peternewman peternewman Nov 14, 2019

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bash is not the default shell but it is available, whether installed or not is a different story but we can and should make it a dependency.

Why? If you've tried to install OLA on say Windows, adding even more dependencies just makes it even harder, likewise it's more slightly different versions of stuff to support, it's taken us long enough to get most stuff compiling across Linux, OS X, *BSD and Windows. TBH if we were going to do anything, adding perl would probably be the sensible choice, as it's standardised, has been around forever so is well deployed and would also fix these sed incompatibilities.

grep -R '#! /bin/bash' . | wc -l returns 41 on the OLA source directory so saying we depend on bash is reasonable if not necessary.

Try running that again in a clean checkout, you'll find all those ones with spaces are from Makefile magic; I don't know what it does if you don't have bash, but there would be an option to do some magic.

In addition to that /bin/sh causes a crapshoot of unpredictable shell interpreters where each distro is running it through whatever sh-like solution they happen to like and stuff works or doesn't work while bash is bash is bash (except maybe for version stuff but unless we use some cutting edge bash feature we're not likely to run into that).

It's really not that hard, there are even tools to help:
https://wiki.ubuntu.com/DashAsBinSh
https://linux.die.net/man/1/checkbashisms

And grep -R '#!/bin/bash' . | wc -l returns 9

So these are the actual ones we'd need to look at, GitHub finds 7:
https://github.com/OpenLightingProject/ola/search?q=%22%2Fbin%2Fbash%22&unscoped_q=%22%2Fbin%2Fbash%22

So the ones in include/ are the ones actually run automatically during the build. I was about to have to agree with you, then I looked a bit more carefully:

ola/include/ola/Makefile.mk

Line 48 in d101097

sh $(top_srcdir)/include/ola/make_plugin_id.sh $(top_srcdir)/common/protocol/Ola.proto > $(top_builddir)/include/ola/plugin_id.h

I'm no expert, but I'm fairly confident that means it runs it via sh and will therefore actually use your sh interpreter rather than whatever is in the shebang line. So we should probably remove that bug in the files by changing /bin/bash to /bin/sh, but its probably having no impact to the build.

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@Keeper-of-the-Keys Keeper-of-the-Keys Nov 14, 2019 •
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Why? If you've tried to install OLA on say Windows, adding even more dependencies just makes it even harder, likewise it's more slightly different versions of stuff to support, it's taken us long enough to get most stuff compiling across Linux, OS X, *BSD and Windows. TBH if we were going to do anything, adding perl would probably be the sensible choice, as it's standardised, has been around forever so is well deployed and would also fix these sed incompatibilities.

If bash was some exotic shell that was not in wide use I would absolutely agree with you, however bash is actually very well established to the point that it is even available for windows iirc, it may not be an ISO standard but bash X.Y on OS A will behave the same and bash X.Y on OS B (and I think this may in general even apply for X.y and X.z)

(...)

It's really not that hard, there are even tools to help:
https://wiki.ubuntu.com/DashAsBinSh
https://linux.die.net/man/1/checkbashisms

This script that we are currently discussing is a live example of /bin/sh not behaving the same across different platforms while on OSX it was doing what you expected it to do it was not doing so on Debian based distros that use dash for sh and this script was not doing anything crazy complicated but the different globbing/parsing behaviors of the different sh implementations killed consistent results.

So these are the actual ones we'd need to look at, GitHub finds 7:
https://github.com/OpenLightingProject/ola/search?q=%22%2Fbin%2Fbash%22&unscoped_q=%22%2Fbin%2Fbash%22

I think we have better things to do with our time bash is easily installed and widely available.

Also note that according to the documentation about installing on Windows bash is the actual shell used there through mingw (though the MSYS part of mingw seems to be dead so that may not be wise, but an alternative is out there - MSYS2 ) and MS has released a "Linux on windows" environment this year which seems to obviate the need for mingw.

https://wiki.openlighting.org/index.php/Building_OLA_for_Windows
https://www.msys2.org/
https://itsfoss.com/install-bash-on-windows/

Both MSYS and MSYS2 provide bash shells as does "Linux on Windows", FreeBSD may not ship with it but it's installable with ease

So the ones in include/ are the ones actually run automatically during the build. I was about to have to agree with you, then I looked a bit more carefully:

ola/include/ola/Makefile.mk

Line 48 in d101097

sh $(top_srcdir)/include/ola/make_plugin_id.sh $(top_srcdir)/common/protocol/Ola.proto > $(top_builddir)/include/ola/plugin_id.h

I'm no expert, but I'm fairly confident that means it runs it via sh and will therefore actually use your sh interpreter rather than whatever is in the shebang line. So we should probably remove that bug in the files by changing /bin/bash to /bin/sh, but its probably having no impact to the build.

As far as I know you are correct.


# A simple script to build a C++ header file containing the plugin description
# from the plugin's README.md
# The output file then contains one variable 'plugin_description'.

set -e

if [ $# != 2 ]; then
echo "Usage: convert_README_to_header.sh <plugin path> <outfile path>";
echo "<plugin path>: path to plugin dir, e.g. plugins/artnet";
Expand All @@ -30,8 +32,9 @@ outfilename=`basename $outfile`;
# See http://stackoverflow.com/a/16576291
# On Mac OS's sed, \n is not recognized as a newline character, but
# \[actual newline] works
desc=`sed -e ':a' -e 'N' -e '$!ba' -e 's/\"/\\\"/g' -e 's/\n/\\\\n"\\
"/g' "$path/README.md"`;
desc=`sed -e ':a' -e 'N' -e '$!ba' -e 's/\\\/\\\\\\\/g' -e 's/\"/\\\"/g' \
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@peternewman peternewman Jan 21, 2020

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I assume s/\\\/\\\\\\\/g is trying to escape a backslash, or an escaped backslash? I don't think there are currently enough backslashes, you've got three replaced with seven. I think the shell will eat half of them, leaving s/\/\\\/g, which sed would interpret as an escaped / followed by a \ and escaped /, but with no substitution operators. I think you actually want four and eight, which boils down to two/four and therefore one/two. See the quote escaping for example.

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@Keeper-of-the-Keys Keeper-of-the-Keys Jan 25, 2020

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We're escaping backslash:

  • first for bash so sed 'sees' only 2
  • then for sed since backslash has significance there too

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@peternewman peternewman Jan 27, 2020

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* first for bash so sed 'sees' only 2

We'll need one per sed backslash (escaping or real), rather than one in total.

* then for sed since backslash has significance there too

Likewise here.

I believe you're trying to logically replace \ with \\?

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@Keeper-of-the-Keys Keeper-of-the-Keys Jan 27, 2020

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Yes because backslash also has significance in C into which the readme is ultimately converted.

-e 's/\n/\\\\n\"\\
\"/g' "$path/README.md"`;

identifier=`echo "PLUGINS_${plugin}_${outfilename%.h}_H_" | tr '[:lower:]' '[:upper:]'`

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