[git commit] hush: fix comment parsing in `cmd`, closes 10421

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=25f3b737dc04bb84fb593ace33a5c360163bd4e4
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

function                                             old     new   delta
parse_stream                                        2692    2690      -2

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 shell/ash_test/ash-parsing/comment2.right   |  4 ++++
 shell/ash_test/ash-parsing/comment2.tests   | 13 +++++++++++++
 shell/hush.c                                | 17 +++++++++++++----
 shell/hush_test/hush-parsing/comment2.right |  4 ++++
 shell/hush_test/hush-parsing/comment2.tests | 13 +++++++++++++
 5 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/shell/ash_test/ash-parsing/comment2.right b/shell/ash_test/ash-parsing/comment2.right
new file mode 100644
index 0000000..ee6e49a
--- /dev/null
+++ b/shell/ash_test/ash-parsing/comment2.right
@@ -0,0 +1,4 @@
+Ok1
+Ok2
+Ok5
+Ok6
diff --git a/shell/ash_test/ash-parsing/comment2.tests b/shell/ash_test/ash-parsing/comment2.tests
new file mode 100755
index 0000000..b7adad9
--- /dev/null
+++ b/shell/ash_test/ash-parsing/comment2.tests
@@ -0,0 +1,13 @@
+echo "`echo Ok1 #comment is ignored`"
+echo `echo Ok2 #comment is ignored`
+#
+# Surprisingly, bash does not handle comments in $()
+# the same way as in ``. "#" causes the rest of the line, _including_ )",
+# to be ignored. These lines would cause an error:
+#echo "$(echo Ok3 #comment is ignored)"
+#echo $(echo Ok4 #comment is ignored)
+#
+echo "$(echo Ok5 #comment is ignored
+)"
+echo $(echo Ok6 #comment is ignored
+)
diff --git a/shell/hush.c b/shell/hush.c
index d27550b..708555a 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -5140,14 +5140,23 @@ static struct pipe *parse_stream(char **pstring,
 		case '#':
 			if (dest.length == 0 && !dest.has_quoted_part) {
 				/* skip "#comment" */
+				/* note: we do not add it to &ctx.as_string */
+/* TODO: in bash:
+ * comment inside $() goes to the next \n, even inside quoted string (!):
+ * cmd "$(cmd2 #comment)" - syntax error
+ * cmd "`cmd2 #comment`" - ok
+ * We accept both (comment ends where command subst ends, in both cases).
+ */
 				while (1) {
 					ch = i_peek(input);
-					if (ch == EOF || ch == '\n')
+					if (ch == '\n') {
+						nommu_addchr(&ctx.as_string, '\n');
+						break;
+					}
+					ch = i_getch(input);
+					if (ch == EOF)
 						break;
-					i_getch(input);
-					/* note: we do not add it to &ctx.as_string */
 				}
-				nommu_addchr(&ctx.as_string, '\n');
 				continue; /* back to top of while (1) */
 			}
 			break;
diff --git a/shell/hush_test/hush-parsing/comment2.right b/shell/hush_test/hush-parsing/comment2.right
new file mode 100644
index 0000000..ee6e49a
--- /dev/null
+++ b/shell/hush_test/hush-parsing/comment2.right
@@ -0,0 +1,4 @@
+Ok1
+Ok2
+Ok5
+Ok6
diff --git a/shell/hush_test/hush-parsing/comment2.tests b/shell/hush_test/hush-parsing/comment2.tests
new file mode 100755
index 0000000..b7adad9
--- /dev/null
+++ b/shell/hush_test/hush-parsing/comment2.tests
@@ -0,0 +1,13 @@
+echo "`echo Ok1 #comment is ignored`"
+echo `echo Ok2 #comment is ignored`
+#
+# Surprisingly, bash does not handle comments in $()
+# the same way as in ``. "#" causes the rest of the line, _including_ )",
+# to be ignored. These lines would cause an error:
+#echo "$(echo Ok3 #comment is ignored)"
+#echo $(echo Ok4 #comment is ignored)
+#
+echo "$(echo Ok5 #comment is ignored
+)"
+echo $(echo Ok6 #comment is ignored
+)