[PATCH] input: Only skip blank lines on PS1

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>]

On Wed, Jan 04, 2023 at 11:18:49AM +0000, Harald van Dijk wrote:
> 
> One is that because of what you say, the history recording for commands
> greater than BUFSIZ is already buggy, but unlikely to pose a problem in
> practice currently because normally, people don't write such long commands.

It's not just that people don't write long lines, it's the fact
that most people use the shell with a terminal device in canonical
mode and the line length is capped in canonical mode to some value
less than 8K.

> Another is that the stripping of blank lines from history breaks when blank
> lines are significant, as in
> 
>   $ cat <<EOF
>   > hello
>   >
>   > world
>   > EOF
>   hello
> 
>   world
>   $ fc 1
>   26
>   q
>   hello
>   world
> 
> Note how the blank line was lost.
> 
> If there was already "something" (as the code puts it), then when more data
> is appended, blanks must be preserved.

Good point.  This patch should fix it.

---8<---
Blank line should not be skipped if they're found on PS2.

Reported-by: Harald van Dijk <harald@xxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

diff --git a/src/input.c b/src/input.c
index 7b37ae2..5dcc8a2 100644
--- a/src/input.c
+++ b/src/input.c
@@ -254,6 +254,7 @@ retry:
 
 static int preadbuffer(void)
 {
+	int first = whichprompt == 1;
 	int something;
 	char savec;
 	int more;
@@ -279,7 +280,7 @@ again:
 	q = parsefile->nextc;
 
 	/* delete nul characters */
-	something = 0;
+	something = !first;
 	for (;;) {
 		int c;
 
@@ -327,7 +328,7 @@ check:
 	if (parsefile->fd == 0 && hist && something) {
 		HistEvent he;
 		INTOFF;
-		history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND,
+		history(hist, &he, first ? H_ENTER : H_APPEND,
 			parsefile->nextc);
 		INTON;
 	}
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt