[PATCH v3] help.c: configurable suggestions

[Drew DeVault <sir@cmpwn.com>]

This allows users to disable guessing the commands or options that they
meant to use.

Signed-off-by: Drew DeVault <sir@cmpwn.com>
---
Thanks for being patient with me, Junio - I didn't entirely grok what
you were getting at in your initial review.

 Documentation/config/help.txt | 14 +++++++-------
 help.c                        | 33 +++++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/Documentation/config/help.txt b/Documentation/config/help.txt
index 224bbf5a28..dea236268a 100644
--- a/Documentation/config/help.txt
+++ b/Documentation/config/help.txt
@@ -8,13 +8,13 @@ help.format::
 	the default. 'web' and 'html' are the same.
 
 help.autoCorrect::
-	Automatically correct and execute mistyped commands after
-	waiting for the given number of deciseconds (0.1 sec). If more
-	than one command can be deduced from the entered text, nothing
-	will be executed.  If the value of this option is negative,
-	the corrected command will be executed immediately. If the
-	value is 0 - the command will be just shown but not executed.
-	This is the default.
+	If git detects typos and can identify exactly one valid command similar
+	to the error, git will automatically run the intended command after
+	waiting a duration of time defined by this configuration value in
+	deciseconds (0.1 sec).  If this value is 0, the suggested corrections
+	will be shown, but not executed. If "immediate", the suggested command
+	is run immediately. If "never", suggestions are not shown at all. The
+	default value is zero.
 
 help.htmlPath::
 	Specify the path where the HTML documentation resides. File system paths
diff --git a/help.c b/help.c
index 919cbb9206..61a7c1ea17 100644
--- a/help.c
+++ b/help.c
@@ -472,12 +472,26 @@ int is_in_cmdlist(struct cmdnames *c, const char *s)
 static int autocorrect;
 static struct cmdnames aliases;
 
+#define AUTOCORRECT_NEVER (-2)
+#define AUTOCORRECT_IMMEDIATELY (-1)
+
 static int git_unknown_cmd_config(const char *var, const char *value, void *cb)
 {
 	const char *p;
 
-	if (!strcmp(var, "help.autocorrect"))
-		autocorrect = git_config_int(var,value);
+	if (!strcmp(var, "help.autocorrect")) {
+		if (!value)
+			return config_error_nonbool(var);
+		if (!strcmp(value, "never")) {
+			autocorrect = AUTOCORRECT_NEVER;
+		} else if (!strcmp(value, "immediate")) {
+			autocorrect = AUTOCORRECT_IMMEDIATELY;
+		} else {
+			int v = git_config_int(var, value);
+			autocorrect = (v < 0)
+				? AUTOCORRECT_IMMEDIATELY : v;
+		}
+	}
 	/* Also use aliases for command lookup */
 	if (skip_prefix(var, "alias.", &p))
 		add_cmdname(&aliases, p, strlen(p));
@@ -525,6 +539,11 @@ const char *help_unknown_cmd(const char *cmd)
 
 	read_early_config(git_unknown_cmd_config, NULL);
 
+	if (autocorrect == AUTOCORRECT_NEVER) {
+		fprintf_ln(stderr, _("git: '%s' is not a git command. See 'git --help'."), cmd);
+		exit(1);
+	}
+
 	load_command_list("git-", &main_cmds, &other_cmds);
 
 	add_cmd_list(&main_cmds, &aliases);
@@ -594,7 +613,7 @@ const char *help_unknown_cmd(const char *cmd)
 			   _("WARNING: You called a Git command named '%s', "
 			     "which does not exist."),
 			   cmd);
-		if (autocorrect < 0)
+		if (autocorrect == AUTOCORRECT_IMMEDIATELY)
 			fprintf_ln(stderr,
 				   _("Continuing under the assumption that "
 				     "you meant '%s'."),
@@ -706,10 +725,16 @@ NORETURN void help_unknown_ref(const char *ref, const char *cmd,
 			       const char *error)
 {
 	int i;
-	struct string_list suggested_refs = guess_refs(ref);
+	struct string_list suggested_refs;
 
 	fprintf_ln(stderr, _("%s: %s - %s"), cmd, ref, error);
 
+	if (autocorrect == AUTOCORRECT_NEVER) {
+		exit(1);
+	}
+
+	suggested_refs = guess_refs(ref);
+
 	if (suggested_refs.nr > 0) {
 		fprintf_ln(stderr,
 			   Q_("\nDid you mean this?",
-- 
2.29.2