[PATCH 3/3] [programs/cmd] Handle unechoed rem commands inside a (..) section

[Jason Edmeades]

Fixes bug#45729

When processing a (..) multiline section, each line is processed and if it starts with
a '@' it is not echoed, but more importantly if is 'rem' then anything else on that line
should be ignored. The reported issue was that a pipe was being executed when it was
hidden behind a rem, which was trigged by the preceeding '@' character not being skipped.

Signed-off-by: Jason Edmeades <us at edmeades.me.uk>
---
 programs/cmd/tests/test_builtins.cmd     |  6 ++++++
 programs/cmd/tests/test_builtins.cmd.exp |  1 +
 programs/cmd/wcmdmain.c                  | 13 +++++++++++--
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/programs/cmd/tests/test_builtins.cmd b/programs/cmd/tests/test_builtins.cmd
index bed395091e..79233d8d6f 100644
--- a/programs/cmd/tests/test_builtins.cmd
+++ b/programs/cmd/tests/test_builtins.cmd
@@ -1427,6 +1427,12 @@ for /L %%i in (2,2,1) do (
   echo %%i
   echo FAILED
 )
+echo --- rems inside for loops
+for /f %%i IN ("hello") DO (
+   REM foo|echo ERROR unexpected execution 1
+   @REM foo|echo ERROR unexpected execution 2
+   @     REM foo|echo ERROR unexpected execution 3
+)
 echo --- ifs inside for loops
 for %%i in (test) do (
     echo a1
diff --git a/programs/cmd/tests/test_builtins.cmd.exp b/programs/cmd/tests/test_builtins.cmd.exp
index 5cca037a30..797a9cc8ae 100644
--- a/programs/cmd/tests/test_builtins.cmd.exp
+++ b/programs/cmd/tests/test_builtins.cmd.exp
@@ -996,6 +996,7 @@ ErrorLevel 0
 -1
 1
 3
+--- rems inside for loops
 --- ifs inside for loops
 a1
 b1
diff --git a/programs/cmd/wcmdmain.c b/programs/cmd/wcmdmain.c
index c8a41d3a80..5ef4a2bf34 100644
--- a/programs/cmd/wcmdmain.c
+++ b/programs/cmd/wcmdmain.c
@@ -2308,12 +2308,21 @@ WCHAR *WCMD_ReadAndParseLine(const WCHAR *optionalcmd, CMD_LIST **output, HANDLE
 
         } while (*extraData == 0x00);
         curPos = extraSpace;
-        if (context) handleExpansion(extraSpace, FALSE, FALSE);
+
+        /* Skip preceding whitespace */
+        while (*curPos == ' ' || *curPos == '\t') curPos++;
+
+        /* Replace env vars if in a batch context */
+        if (context) handleExpansion(curPos, FALSE, FALSE);
+
         /* Continue to echo commands IF echo is on and in batch program */
-        if (context && echo_mode && extraSpace[0] && (extraSpace[0] != '@')) {
+        if (context && echo_mode && *curPos && *curPos != '@') {
           WCMD_output_asis(extraSpace);
           WCMD_output_asis(newlineW);
         }
+
+        /* Skip repeated 'no echo' characters and whitespace */
+        while (*curPos == '@' || *curPos == ' ' || *curPos == '\t') curPos++;
       }
     }
 
-- 
2.17.1