Re: [PATCH] sub-process: print the cmd when a capability is unsupported

On 15 Aug 2017, at 19:36, Christian Couder [off-list ref] wrote:

In handshake_capabilities() we use warning() when a capability
is not supported, so the exit code of the function is 0 and no
further error is shown. This is a problem because the warning
message doesn't tell us which subprocess cmd failed.

On the contrary if we cannot write a packet from this function,
we use error() and then subprocess_start() outputs:

   initialization for subprocess '<cmd>' failed

so we can know which subprocess cmd failed.

Let's improve the warning() message, so that we can know which
subprocess cmd failed.

Signed-off-by: Christian Couder <redacted>
---
sub-process.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/sub-process.c b/sub-process.c
index 6edb97c1c6..6b133f8dce 100644
--- a/sub-process.c
+++ b/sub-process.c

@@ -158,7 +158,8 @@ static int handshake_version(struct child_process *process,

static int handshake_capabilities(struct child_process *process,
				  struct subprocess_capability *capabilities,
-				  unsigned int *supported_capabilities)
+				  unsigned int *supported_capabilities,
+				  const char *cmd)
{
	int i;
	char *line;

@@ -184,8 +185,8 @@ static int handshake_capabilities(struct child_process *process,

			if (supported_capabilities)
				*supported_capabilities |= capabilities[i].flag;
		} else {
-			warning("external filter requested unsupported filter capability '%s'",
-				p);
+			warning("subprocess '%s' requested unsupported capability '%s'",
+				cmd, p);