commit f3daa4525b1816e475fbfe7add6f3c4a33b13944
author Mohamed Akram <mohd.akram@outlook.com> Sat Jul 06 17:12:09 2024 +0200
committer Christian Brabandt <cb@256bit.org> Sat Jul 06 17:12:09 2024 +0200
tree 46fc7a5fc6c63a44ee6b558d32e767e0f62c3687
parent 84ca1388d8d9a9858f37a5c0586527589cbdadda

patch 9.1.0535: newline escape wrong in ex mode

Problem:  newline escape wrong in ex mode (Konrad Schwarz)
Solution: partly revert patch 7.3.014, remove backslash in front of a
          newline when not in prompt mode in ex line mode
          (Mohamed Akram)

This fixes newline escaping to allow passing multiple commands to
":global", multiple lines to shell commands, and ending lines in append
mode with backslashes. This should fix a POSIX/(traditional) VI
incompatiblity.

This reverts a previous incorrect attempt at patch v7.3.014 to fix
append mode which removed half of trailing backslashes which lead to,
eg. the following two commands being parsed as having a different number
of backslashes:

```
!echo foo\\\
```

```
!echo foo\\ \
```

fixes: #6135
fixes: #7244
closes: #15120

Signed-off-by: Mohamed Akram <mohd.akram@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/ex_docmd.c

diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 59d3db4..1dc28bc 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -2341,12 +2341,7 @@
     {
 	for (p = ea.arg; *p; ++p)
 	{
-	    // Remove one backslash before a newline, so that it's possible to
-	    // pass a newline to the shell and also a newline that is preceded
-	    // with a backslash.  This makes it impossible to end a shell
-	    // command in a backslash, but that doesn't appear useful.
-	    // Halving the number of backslashes is incompatible with previous
-	    // versions.
+	    // Remove one backslash before a newline
 	    if (*p == '\\' && p[1] == '\n')
 		STRMOVE(p, p + 1);
 	    else if (*p == '\n' && !(ea.argt & EX_EXPR_ARG))

src/ex_getln.c

diff --git a/src/ex_getln.c b/src/ex_getln.c
index f05259b..51a38e5 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -3138,31 +3138,15 @@
 	windgoto(msg_row, msg_col);
 	pend = (char_u *)(line_ga.ga_data) + line_ga.ga_len;
 
-	// We are done when a NL is entered, but not when it comes after an
-	// odd number of backslashes, that results in a NUL.
-	if (line_ga.ga_len > 0 && pend[-1] == '\n')
+	// We are done when a NL is entered, but not when it comes after a
+	// backslash in prompt mode.
+	if (line_ga.ga_len > 0 && pend[-1] == '\n'
+		&& (line_ga.ga_len <= 1 || pend[-2] != '\\' || !promptc))
 	{
-	    int bcount = 0;
-
-	    while (line_ga.ga_len - 2 >= bcount && pend[-2 - bcount] == '\\')
-		++bcount;
-
-	    if (bcount > 0)
-	    {
-		// Halve the number of backslashes: "\NL" -> "NUL", "\\NL" ->
-		// "\NL", etc.
-		line_ga.ga_len -= (bcount + 1) / 2;
-		pend -= (bcount + 1) / 2;
-		pend[-1] = '\n';
-	    }
-
-	    if ((bcount & 1) == 0)
-	    {
-		--line_ga.ga_len;
-		--pend;
-		*pend = NUL;
-		break;
-	    }
+	    --line_ga.ga_len;
+	    --pend;
+	    *pend = NUL;
+	    break;
 	}
     }
 

src/testdir/test_ex_mode.vim

diff --git a/src/testdir/test_ex_mode.vim b/src/testdir/test_ex_mode.vim
index 59c28f3..12e983f 100644
--- a/src/testdir/test_ex_mode.vim
+++ b/src/testdir/test_ex_mode.vim
Binary files differ

src/version.c

diff --git a/src/version.c b/src/version.c
index 2371355..ffbc13e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    535,
+/**/
     534,
 /**/
     533,