Merge branch 'jk/log-warn-on-bogus-encoding' into maint

Doc update plus improved error reporting.

* jk/log-warn-on-bogus-encoding:
  docs: use "character encoding" to refer to commit-object encoding
  logmsg_reencode(): warn when iconv() fails

Author: gitster

Documentation/config/gui.txt

@@ -11,7 +11,7 @@ gui.displayUntracked::
 	in the file list. The default is "true".
 
 gui.encoding::
-	Specifies the default encoding to use for displaying of
+	Specifies the default character encoding to use for displaying of
 	file contents in linkgit:git-gui[1] and linkgit:gitk[1].
 	It can be overridden by setting the 'encoding' attribute
 	for relevant files (see linkgit:gitattributes[5]).

Documentation/pretty-options.txt

@@ -33,14 +33,16 @@ people using 80-column terminals.
 	used together.
 
 --encoding=<encoding>::
-	The commit objects record the encoding used for the log message
+	Commit objects record the character encoding used for the log message
 	in their encoding header; this option can be used to tell the
 	command to re-code the commit log message in the encoding
 	preferred by the user.  For non plumbing commands this
 	defaults to UTF-8. Note that if an object claims to be encoded
 	in `X` and we are outputting in `X`, we will output the object
 	verbatim; this means that invalid sequences in the original
-	commit may be copied to the output.
+	commit may be copied to the output. Likewise, if iconv(3) fails
+	to convert the commit, we will output the original object
+	verbatim, along with a warning.
 
 --expand-tabs=<n>::
 --expand-tabs::

pretty.c

@@ -671,7 +671,11 @@ const char *repo_logmsg_reencode(struct repository *r,
 	 * If the re-encoding failed, out might be NULL here; in that
 	 * case we just return the commit message verbatim.
 	 */
-	return out ? out : msg;
+	if (!out) {
+		warning("unable to reencode commit to '%s'", output_encoding);
+		return msg;
+	}
+	return out;
 }
 
 static int mailmap_name(const char **email, size_t *email_len,

t/t4210-log-i18n.sh

@@ -131,4 +131,11 @@ do
 	fi
 done
 
+test_expect_success 'log shows warning when conversion fails' '
+	enc=this-encoding-does-not-exist &&
+	git log -1 --encoding=$enc 2>err &&
+	echo "warning: unable to reencode commit to ${SQ}${enc}${SQ}" >expect &&
+	test_cmp expect err
+'
+
 test_done