bash: '\n' after command substitution in $PS1 causes error

[k-takata]

When I use \n after command substitution in $PS1, it causes syntax error:

$ PS1='$(date)\n\$ '
-bash: command substitution: line 1: syntax error near unexpected token `)'
-bash: command substitution: line 1: `date)'

It should not cause the error.
If I remove the \n after $(date), it works fine:

$ PS1='$(date)\$ '
Mon Jan 27 19:16:55 JST 2020$ 

Using backquotes instead of $() also works fine:

$ PS1='`date`\n\$ '
Mon Jan 27 19:21:51 JST 2020
$ 

Setting PS1='$(date)\n\$ ' works fine on Cygwin, so this seems an MSYS2 specific issue.

See also: https://stackoverflow.com/questions/21517281/ps1-command-substitution-fails-when-containing-newlines-on-msys-bash

[k-takata]

If I revert the following hunks, the issue disappears:

MSYS2-packages/bash/0005-bash-4.3-msys2-fix-lineendings.patch

Lines 86 to 93 in 8a97a6c

	- return (*(bash_input.getter)) ();
	+#ifdef __MSYS__
	+ int c;
	+ while ((c = (*(bash_input.getter)) ()) == '\r');
	+ return c;
	+#else
	+ return (*(bash_input.getter)) ();
	+#endif

MSYS2-packages/bash/0005-bash-4.3-msys2-fix-lineendings.patch

Lines 182 to 189 in 8a97a6c

	- return (*(bash_input.getter)) ();
	+#ifdef __MSYS__
	+ int c;
	+ while ((c = (*(bash_input.getter)) ()) == '\r');
	+ return c;
	+#else
	+ return (*(bash_input.getter)) ();
	+#endif

MSYS2-packages/bash/0005-bash-4.3-msys2-fix-lineendings.patch

Lines 197 to 200 in 8a97a6c

	+#ifdef __MSYS__
	+ if (c == '\r')
	+ continue;
	+#endif

[stirwl]

I have same issue too.
My bash version is 5.2.15(1)-release (x86_64-pc-msys)

[GeekDuanLian]

I recently switched from Cygwin to MSYS2 and I have the same problem, and this problem seems to be only on MSYS2, I don't experience it on any of the remaining platforms.

Hope this issue can be fixed soon.

[stirwl]

I add \e[0m\]\n at the line end. It works fine.

[akinomyoga]

This hasn't yet been fixed after four years since the report. Did anyone make an effort to fix this problem? @lazka @Alexpux Who are responsible for the Bash package in MSYS2?

This causes many error reports as follows. This is not a complete list. These are just the reports to a repository that I maintain and some others that can be quickly found by Google search.

• 2014-02 backticks - PS1 command substitution fails when containing newlines on msys bash - Stack Overflow
• 2014-02 MSYS2 / Tickets / #17 PS1 command substitution
• 2015-07 I'd like to switch to git-for-windows: what are the differences with git-bash ?
• 2016-03 Why does a newline in PS1 throw a syntax error in Git for Windows bash? - Stack Overflow
• 2017-02 Git for Windows 2.xでプロンプトの設定(PS1)にブランチ名と改行を入れるとsyntax errorになる - みちしるべ
• 2021-03 Git Bash: Terminal starts with error after changing theme · Issue #211 · ohmybash/oh-my-bash
• 2021-07 Newlines and Carriage Returns Following $() Command Substitution Cause Bash Parse Error · Issue #3303 · git-for-windows/git
• 2021-11 GitBash on windows: syntax error · Issue #260 · ohmybash/oh-my-bash
• 2022-01 bash - Error PS1 git functions - conflict between Gitbash vs Cygwin - Stack Overflow
• 2023-12 Anyon with the same error? Theme sexy · Issue #512 · ohmybash/oh-my-bash
• 2024-02 Git Bash syntax error in Oh My Bash 'Sexy' Theme (solved) · ohmybash/oh-my-bash · Discussion #528

For individual personal setting, "the fix" suggested in some of the threads or #1839 (comment) might work. However, we don't want to include in a larger shared framework such specific workarounds caused by a package unmaintained for ten years unless there is a reason that this cannot be fixed in the origin.

[akinomyoga]

@lazka Who is responsible for the Bash package?

[ElectricRCAircraftGuy]

Workarounds and more info on Stack Overflow:

1. My Q&A: Cannot use command substitution inside Git Bash on Windows: "bash: command substitution: line 1: syntax error near unexpected token `)'"
2. PS1 command substitution fails when containing newlines on msys bash

[k-takata]

As I wrote in #4477, the issue also occurs in Cygwin bash when the igncr option is set.
I've sent a patch to the Cygwin mailing list:
https://cygwin.com/pipermail/cygwin/2024-May/255980.html