Merge branch 'nd/complete-config-vars'

Continuing with the idea to programatically enumerate various
pieces of data required for command line completion, teach the
codebase to report the list of configuration variables
subcommands care about to help complete them.

* nd/complete-config-vars:
  completion: complete general config vars in two steps
  log-tree: allow to customize 'grafted' color
  completion: support case-insensitive config vars
  completion: keep other config var completion in camelCase
  completion: drop the hard coded list of config vars
  am: move advice.amWorkDir parsing back to advice.c
  advice: keep config name in camelCase in advice_config[]
  fsck: produce camelCase config key names
  help: add --config to list all available config
  fsck: factor out msg_id_info[] lazy initialization code
  grep: keep all colors in an array
  Add and use generic name->id mapping code for color slot parsing

21 files changed, 445 insertions, 553 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index ab641bf5a..1cc18a828 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1162,7 +1162,8 @@ color.diff.<slot>::
 color.decorate.<slot>::
 	Use customized color for 'git log --decorate' output.  `<slot>` is one
 	of `branch`, `remoteBranch`, `tag`, `stash` or `HEAD` for local
-	branches, remote-tracking branches, tags, stash and HEAD, respectively.
+	branches, remote-tracking branches, tags, stash and HEAD, respectively
+	and `grafted` for grafted commits.
 
 color.grep::
 	When set to `always`, always highlight matches.  When `false` (or
diff --git a/Documentation/git-help.txt b/Documentation/git-help.txt
index a40fc38d8..83d25d825 100644
--- a/Documentation/git-help.txt
+++ b/Documentation/git-help.txt
@@ -45,6 +45,11 @@ OPTIONS
 	When used with `--verbose` print description for all recognized
 	commands.
 
+-c::
+--config::
+	List all available configuration variables. This is a short
+	summary of the list in linkgit:git-config[1].
+
 -g::
 --guides::
 	Prints a list of useful guides on the standard output. This
diff --git a/advice.c b/advice.c
index 370a56d05..52aa85bdf 100644
--- a/advice.c
+++ b/advice.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "config.h"
 #include "color.h"
+#include "help.h"
 
 int advice_push_update_rejected = 1;
 int advice_push_non_ff_current = 1;
@@ -16,6 +17,7 @@ int advice_implicit_identity = 1;
 int advice_detached_head = 1;
 int advice_set_upstream_failure = 1;
 int advice_object_name_warning = 1;
+int advice_amworkdir = 1;
 int advice_rm_hints = 1;
 int advice_add_embedded_repo = 1;
 int advice_ignored_hook = 1;
@@ -53,28 +55,29 @@ static struct {
 	const char *name;
 	int *preference;
 } advice_config[] = {
-	{ "pushupdaterejected", &advice_push_update_rejected },
-	{ "pushnonffcurrent", &advice_push_non_ff_current },
-	{ "pushnonffmatching", &advice_push_non_ff_matching },
-	{ "pushalreadyexists", &advice_push_already_exists },
-	{ "pushfetchfirst", &advice_push_fetch_first },
-	{ "pushneedsforce", &advice_push_needs_force },
-	{ "statushints", &advice_status_hints },
-	{ "statusuoption", &advice_status_u_option },
-	{ "commitbeforemerge", &advice_commit_before_merge },
-	{ "resolveconflict", &advice_resolve_conflict },
-	{ "implicitidentity", &advice_implicit_identity },
-	{ "detachedhead", &advice_detached_head },
-	{ "setupstreamfailure", &advice_set_upstream_failure },
-	{ "objectnamewarning", &advice_object_name_warning },
-	{ "rmhints", &advice_rm_hints },
-	{ "addembeddedrepo", &advice_add_embedded_repo },
-	{ "ignoredhook", &advice_ignored_hook },
-	{ "waitingforeditor", &advice_waiting_for_editor },
-	{ "graftfiledeprecated", &advice_graft_file_deprecated },
+	{ "pushUpdateRejected", &advice_push_update_rejected },
+	{ "pushNonFFCurrent", &advice_push_non_ff_current },
+	{ "pushNonFFMatching", &advice_push_non_ff_matching },
+	{ "pushAlreadyExists", &advice_push_already_exists },
+	{ "pushFetchFirst", &advice_push_fetch_first },
+	{ "pushNeedsForce", &advice_push_needs_force },
+	{ "statusHints", &advice_status_hints },
+	{ "statusUoption", &advice_status_u_option },
+	{ "commitBeforeMerge", &advice_commit_before_merge },
+	{ "resolveConflict", &advice_resolve_conflict },
+	{ "implicitIdentity", &advice_implicit_identity },
+	{ "detachedHead", &advice_detached_head },
+	{ "setupStreamFailure", &advice_set_upstream_failure },
+	{ "objectNameWarning", &advice_object_name_warning },
+	{ "amWorkDir", &advice_amworkdir },
+	{ "rmHints", &advice_rm_hints },
+	{ "addEmbeddedRepo", &advice_add_embedded_repo },
+	{ "ignoredHook", &advice_ignored_hook },
+	{ "waitingForEditor", &advice_waiting_for_editor },
+	{ "graftFileDeprecated", &advice_graft_file_deprecated },
 
 	/* make this an alias for backward compatibility */
-	{ "pushnonfastforward", &advice_push_update_rejected }
+	{ "pushNonFastForward", &advice_push_update_rejected }
 };
 
 void advise(const char *advice, ...)
@@ -122,7 +125,7 @@ int git_default_advice_config(const char *var, const char *value)
 		return 0;
 
 	for (i = 0; i < ARRAY_SIZE(advice_config); i++) {
-		if (strcmp(k, advice_config[i].name))
+		if (strcasecmp(k, advice_config[i].name))
 			continue;
 		*advice_config[i].preference = git_config_bool(var, value);
 		return 0;
@@ -131,6 +134,14 @@ int git_default_advice_config(const char *var, const char *value)
 	return 0;
 }
 
+void list_config_advices(struct string_list *list, const char *prefix)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(advice_config); i++)
+		list_config_item(list, prefix, advice_config[i].name);
+}
+
 int error_resolve_conflict(const char *me)
 {
 	if (!strcmp(me, "cherry-pick"))
diff --git a/advice.h b/advice.h
index 9f5064e82..7e9377864 100644
--- a/advice.h
+++ b/advice.h
@@ -17,6 +17,7 @@ extern int advice_implicit_identity;
 extern int advice_detached_head;
 extern int advice_set_upstream_failure;
 extern int advice_object_name_warning;
+extern int advice_amworkdir;
 extern int advice_rm_hints;
 extern int advice_add_embedded_repo;
 extern int advice_ignored_hook;
diff --git a/builtin/am.c b/builtin/am.c
index 2fc2d1e82..6273ea519 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1827,15 +1827,11 @@ static void am_run(struct am_state *state, int resume)
 		}
 
 		if (apply_status) {
-			int advice_amworkdir = 1;
-
 			printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
 				linelen(state->msg), state->msg);
 
-			git_config_get_bool("advice.amworkdir", &advice_amworkdir);
-
 			if (advice_amworkdir)
-				printf_ln(_("Use 'git am --show-current-patch' to see the failed patch"));
+				advise(_("Use 'git am --show-current-patch' to see the failed patch"));
 
 			die_user_resolve(state);
 		}
diff --git a/builtin/branch.c b/builtin/branch.c
index 5217ba3bd..1876ca9e7 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -22,6 +22,7 @@
 #include "wt-status.h"
 #include "ref-filter.h"
 #include "worktree.h"
+#include "help.h"
 
 static const char * const builtin_branch_usage[] = {
 	N_("git branch [<options>] [-r | -a] [--merged | --no-merged]"),
@@ -55,25 +56,19 @@ enum color_branch {
 	BRANCH_COLOR_UPSTREAM = 5
 };
 
+static const char *color_branch_slots[] = {
+	[BRANCH_COLOR_RESET]	= "reset",
+	[BRANCH_COLOR_PLAIN]	= "plain",
+	[BRANCH_COLOR_REMOTE]	= "remote",
+	[BRANCH_COLOR_LOCAL]	= "local",
+	[BRANCH_COLOR_CURRENT]	= "current",
+	[BRANCH_COLOR_UPSTREAM] = "upstream",
+};
+
 static struct string_list output = STRING_LIST_INIT_DUP;
 static unsigned int colopts;
 
-static int parse_branch_color_slot(const char *slot)
-{
-	if (!strcasecmp(slot, "plain"))
-		return BRANCH_COLOR_PLAIN;
-	if (!strcasecmp(slot, "reset"))
-		return BRANCH_COLOR_RESET;
-	if (!strcasecmp(slot, "remote"))
-		return BRANCH_COLOR_REMOTE;
-	if (!strcasecmp(slot, "local"))
-		return BRANCH_COLOR_LOCAL;
-	if (!strcasecmp(slot, "current"))
-		return BRANCH_COLOR_CURRENT;
-	if (!strcasecmp(slot, "upstream"))
-		return BRANCH_COLOR_UPSTREAM;
-	return -1;
-}
+define_list_config_array(color_branch_slots);
 
 static int git_branch_config(const char *var, const char *value, void *cb)
 {
@@ -86,7 +81,7 @@ static int git_branch_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 	if (skip_prefix(var, "color.branch.", &slot_name)) {
-		int slot = parse_branch_color_slot(slot_name);
+		int slot = LOOKUP_CONFIG(color_branch_slots, slot_name);
 		if (slot < 0)
 			return 0;
 		if (!value)
diff --git a/builtin/clean.c b/builtin/clean.c
index fad533a0a..ab402c204 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -16,6 +16,7 @@
 #include "column.h"
 #include "color.h"
 #include "pathspec.h"
+#include "help.h"
 
 static int force = -1; /* unset */
 static int interactive;
@@ -42,6 +43,15 @@ enum color_clean {
 	CLEAN_COLOR_ERROR = 5
 };
 
+static const char *color_interactive_slots[] = {
+	[CLEAN_COLOR_ERROR]  = "error",
+	[CLEAN_COLOR_HEADER] = "header",
+	[CLEAN_COLOR_HELP]   = "help",
+	[CLEAN_COLOR_PLAIN]  = "plain",
+	[CLEAN_COLOR_PROMPT] = "prompt",
+	[CLEAN_COLOR_RESET]  = "reset",
+};
+
 static int clean_use_color = -1;
 static char clean_colors[][COLOR_MAXLEN] = {
 	[CLEAN_COLOR_ERROR] = GIT_COLOR_BOLD_RED,
@@ -82,22 +92,7 @@ struct menu_stuff {
 	void *stuff;
 };
 
-static int parse_clean_color_slot(const char *var)
-{
-	if (!strcasecmp(var, "reset"))
-		return CLEAN_COLOR_RESET;
-	if (!strcasecmp(var, "plain"))
-		return CLEAN_COLOR_PLAIN;
-	if (!strcasecmp(var, "prompt"))
-		return CLEAN_COLOR_PROMPT;
-	if (!strcasecmp(var, "header"))
-		return CLEAN_COLOR_HEADER;
-	if (!strcasecmp(var, "help"))
-		return CLEAN_COLOR_HELP;
-	if (!strcasecmp(var, "error"))
-		return CLEAN_COLOR_ERROR;
-	return -1;
-}
+define_list_config_array(color_interactive_slots);
 
 static int git_clean_config(const char *var, const char *value, void *cb)
 {
@@ -113,7 +108,7 @@ static int git_clean_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 	if (skip_prefix(var, "color.interactive.", &slot_name)) {
-		int slot = parse_clean_color_slot(slot_name);
+		int slot = LOOKUP_CONFIG(color_interactive_slots, slot_name);
 		if (slot < 0)
 			return 0;
 		if (!value)
diff --git a/builtin/commit.c b/builtin/commit.c
index a842fea66..9bcbb0c25 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -32,6 +32,7 @@
 #include "column.h"
 #include "sequencer.h"
 #include "mailmap.h"
+#include "help.h"
 
 static const char * const builtin_commit_usage[] = {
 	N_("git commit [<options>] [--] <pathspec>..."),
@@ -66,6 +67,18 @@ N_("If you wish to skip this commit, use:\n"
 "Then \"git cherry-pick --continue\" will resume cherry-picking\n"
 "the remaining commits.\n");
 
+static const char *color_status_slots[] = {
+	[WT_STATUS_HEADER]	  = "header",
+	[WT_STATUS_UPDATED]	  = "updated",
+	[WT_STATUS_CHANGED]	  = "changed",
+	[WT_STATUS_UNTRACKED]	  = "untracked",
+	[WT_STATUS_NOBRANCH]	  = "noBranch",
+	[WT_STATUS_UNMERGED]	  = "unmerged",
+	[WT_STATUS_LOCAL_BRANCH]  = "localBranch",
+	[WT_STATUS_REMOTE_BRANCH] = "remoteBranch",
+	[WT_STATUS_ONBRANCH]	  = "branch",
+};
+
 static const char *use_message_buffer;
 static struct lock_file index_lock; /* real index */
 static struct lock_file false_lock; /* used only for partial commits */
@@ -1183,27 +1196,14 @@ static int dry_run_commit(int argc, const char **argv, const char *prefix,
 	return commitable ? 0 : 1;
 }
 
+define_list_config_array_extra(color_status_slots, {"added"});
+
 static int parse_status_slot(const char *slot)
 {
-	if (!strcasecmp(slot, "header"))
-		return WT_STATUS_HEADER;
-	if (!strcasecmp(slot, "branch"))
-		return WT_STATUS_ONBRANCH;
-	if (!strcasecmp(slot, "updated") || !strcasecmp(slot, "added"))
+	if (!strcasecmp(slot, "added"))
 		return WT_STATUS_UPDATED;
-	if (!strcasecmp(slot, "changed"))
-		return WT_STATUS_CHANGED;
-	if (!strcasecmp(slot, "untracked"))
-		return WT_STATUS_UNTRACKED;
-	if (!strcasecmp(slot, "nobranch"))
-		return WT_STATUS_NOBRANCH;
-	if (!strcasecmp(slot, "unmerged"))
-		return WT_STATUS_UNMERGED;
-	if (!strcasecmp(slot, "localBranch"))
-		return WT_STATUS_LOCAL_BRANCH;
-	if (!strcasecmp(slot, "remoteBranch"))
-		return WT_STATUS_REMOTE_BRANCH;
-	return -1;
+
+	return LOOKUP_CONFIG(color_status_slots, slot);
 }
 
 static int git_status_config(const char *k, const char *v, void *cb)
diff --git a/builtin/help.c b/builtin/help.c
index 58e0a5507..8d4f6dd30 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -37,6 +37,7 @@ static const char *html_path;
 
 static int show_all = 0;
 static int show_guides = 0;
+static int show_config;
 static int verbose;
 static unsigned int colopts;
 static enum help_format help_format = HELP_FORMAT_NONE;
@@ -45,6 +46,8 @@ static struct option builtin_help_options[] = {
 	OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
 	OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
 	OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
+	OPT_BOOL('c', "config", &show_config, N_("print all configuration variable names")),
+	OPT_SET_INT_F(0, "config-for-completion", &show_config, "", 2, PARSE_OPT_HIDDEN),
 	OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
 	OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
 			HELP_FORMAT_WEB),
@@ -444,6 +447,19 @@ int cmd_help(int argc, const char **argv, const char *prefix)
 		list_commands(colopts, &main_cmds, &other_cmds);
 	}
 
+	if (show_config) {
+		int for_human = show_config == 1;
+
+		if (!for_human) {
+			list_config_help(for_human);
+			return 0;
+		}
+		setup_pager();
+		list_config_help(for_human);
+		printf("\n%s\n", _("'git help config' for more information"));
+		return 0;
+	}
+
 	if (show_guides)
 		list_common_guides_help();
 
diff --git a/config.c b/config.c
index fbbf0f8e9..a0a6ae198 100644
--- a/config.c
+++ b/config.c
@@ -3245,3 +3245,16 @@ enum config_scope current_config_scope(void)
 	else
 		return current_parsing_scope;
 }
+
+int lookup_config(const char **mapping, int nr_mapping, const char *var)
+{
+	int i;
+
+	for (i = 0; i < nr_mapping; i++) {
+		const char *name = mapping[i];
+
+		if (name && !strcasecmp(var, name))
+			return i;
+	}
+	return -1;
+}
diff --git a/config.h b/config.h
index cdac2fc73..626d4654b 100644
--- a/config.h
+++ b/config.h
@@ -257,4 +257,8 @@ struct key_value_info {
 extern NORETURN void git_die_config(const char *key, const char *err, ...) __attribute__((format(printf, 2, 3)));
 extern NORETURN void git_die_config_linenr(const char *key, const char *filename, int linenr);
 
+#define LOOKUP_CONFIG(mapping, var) \
+	lookup_config(mapping, ARRAY_SIZE(mapping), var)
+int lookup_config(const char **mapping, int nr_mapping, const char *var);
+
 #endif /* CONFIG_H */
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index dd3e92584..dc2b04603 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -2142,9 +2142,24 @@ __git_config_get_set_variables ()
 	__git config $config_file --name-only --list
 }
 
+__git_config_vars=
+__git_compute_config_vars ()
+{
+	test -n "$__git_config_vars" ||
+	__git_config_vars="$(git help --config-for-completion | sort | uniq)"
+}
+
 _git_config ()
 {
-	case "$prev" in
+	local varname
+
+	if [ "${BASH_VERSINFO[0]:-0}" -ge 4 ]; then
+		varname="${prev,,}"
+	else
+		varname="$(echo "$prev" |tr A-Z a-z)"
+	fi
+
+	case "$varname" in
 	branch.*.remote|branch.*.pushremote)
 		__gitcomp_nl "$(__git_remotes)"
 		return
@@ -2242,20 +2257,20 @@ _git_config ()
 		;;
 	branch.*.*)
 		local pfx="${cur%.*}." cur_="${cur##*.}"
-		__gitcomp "remote pushremote merge mergeoptions rebase" "$pfx" "$cur_"
+		__gitcomp "remote pushRemote merge mergeOptions rebase" "$pfx" "$cur_"
 		return
 		;;
 	branch.*)
 		local pfx="${cur%.*}." cur_="${cur#*.}"
 		__gitcomp_direct "$(__git_heads "$pfx" "$cur_" ".")"
-		__gitcomp_nl_append $'autosetupmerge\nautosetuprebase\n' "$pfx" "$cur_"
+		__gitcomp_nl_append $'autoSetupMerge\nautoSetupRebase\n' "$pfx" "$cur_"
 		return
 		;;
 	guitool.*.*)
 		local pfx="${cur%.*}." cur_="${cur##*.}"
 		__gitcomp "
-			argprompt cmd confirm needsfile noconsole norescan
-			prompt revprompt revunmerged title
+			argPrompt cmd confirm needsFile noConsole noRescan
+			prompt revPrompt revUnmerged title
 			" "$pfx" "$cur_"
 		return
 		;;
@@ -2284,14 +2299,14 @@ _git_config ()
 		local pfx="${cur%.*}." cur_="${cur##*.}"
 		__gitcomp "
 			url proxy fetch push mirror skipDefaultUpdate
-			receivepack uploadpack tagopt pushurl
+			receivepack uploadpack tagOpt pushurl
 			" "$pfx" "$cur_"
 		return
 		;;
 	remote.*)
 		local pfx="${cur%.*}." cur_="${cur#*.}"
 		__gitcomp_nl "$(__git_remotes)" "$pfx" "$cur_" "."
-		__gitcomp_nl_append "pushdefault" "$pfx" "$cur_"
+		__gitcomp_nl_append "pushDefault" "$pfx" "$cur_"
 		return
 		;;
 	url.*.*)
@@ -2299,333 +2314,14 @@ _git_config ()
 		__gitcomp "insteadOf pushInsteadOf" "$pfx" "$cur_"
 		return
 		;;
+	*.*)
+		__git_compute_config_vars
+		__gitcomp "$__git_config_vars"
+		;;
+	*)
+		__git_compute_config_vars
+		__gitcomp "$(echo "$__git_config_vars" | sed 's/\.[^ ]*/./g')"
 	esac
-	__gitcomp "
-		add.ignoreErrors
-		advice.amWorkDir
-		advice.commitBeforeMerge
-		advice.detachedHead
-		advice.implicitIdentity
-		advice.pushAlreadyExists
-		advice.pushFetchFirst
-		advice.pushNeedsForce
-		advice.pushNonFFCurrent
-		advice.pushNonFFMatching
-		advice.pushUpdateRejected
-		advice.resolveConflict
-		advice.rmHints
-		advice.statusHints
-		advice.statusUoption
-		advice.ignoredHook
-		alias.
-		am.keepcr
-		am.threeWay
-		apply.ignorewhitespace
-		apply.whitespace
-		branch.autosetupmerge
-		branch.autosetuprebase
-		browser.
-		clean.requireForce
-		color.branch
-		color.branch.current
-		color.branch.local
-		color.branch.plain
-		color.branch.remote
-		color.decorate.HEAD
-		color.decorate.branch
-		color.decorate.remoteBranch
-		color.decorate.stash
-		color.decorate.tag
-		color.diff
-		color.diff.commit
-		color.diff.frag
-		color.diff.func
-		color.diff.meta
-		color.diff.new
-		color.diff.old
-		color.diff.plain
-		color.diff.whitespace
-		color.grep
-		color.grep.context
-		color.grep.filename
-		color.grep.function
-		color.grep.linenumber
-		color.grep.match
-		color.grep.selected
-		color.grep.separator
-		color.interactive
-		color.interactive.error
-		color.interactive.header
-		color.interactive.help
-		color.interactive.prompt
-		color.pager
-		color.showbranch
-		color.status
-		color.status.added
-		color.status.changed
-		color.status.header
-		color.status.localBranch
-		color.status.nobranch
-		color.status.remoteBranch
-		color.status.unmerged
-		color.status.untracked
-		color.status.updated
-		color.ui
-		commit.cleanup
-		commit.gpgSign
-		commit.status
-		commit.template
-		commit.verbose
-		core.abbrev
-		core.askpass
-		core.attributesfile
-		core.autocrlf
-		core.bare
-		core.bigFileThreshold
-		core.checkStat
-		core.commentChar
-		core.commitGraph
-		core.compression
-		core.createObject
-		core.deltaBaseCacheLimit
-		core.editor
-		core.eol
-		core.excludesfile
-		core.fileMode
-		core.fsyncobjectfiles
-		core.gitProxy
-		core.hideDotFiles
-		core.hooksPath
-		core.ignoreStat
-		core.ignorecase
-		core.logAllRefUpdates
-		core.loosecompression
-		core.notesRef
-		core.packedGitLimit
-		core.packedGitWindowSize
-		core.packedRefsTimeout
-		core.pager
-		core.precomposeUnicode
-		core.preferSymlinkRefs
-		core.preloadindex
-		core.protectHFS
-		core.protectNTFS
-		core.quotepath
-		core.repositoryFormatVersion
-		core.safecrlf
-		core.sharedRepository
-		core.sparseCheckout
-		core.splitIndex
-		core.sshCommand
-		core.symlinks
-		core.trustctime
-		core.untrackedCache
-		core.warnAmbiguousRefs
-		core.whitespace
-		core.worktree
-		credential.helper
-		credential.useHttpPath
-		credential.username
-		credentialCache.ignoreSIGHUP
-		diff.autorefreshindex
-		diff.external
-		diff.ignoreSubmodules
-		diff.mnemonicprefix
-		diff.noprefix
-		diff.renameLimit
-		diff.renames
-		diff.statGraphWidth
-		diff.submodule
-		diff.suppressBlankEmpty
-		diff.tool
-		diff.wordRegex
-		diff.algorithm
-		difftool.
-		difftool.prompt
-		fetch.recurseSubmodules
-		fetch.unpackLimit
-		format.attach
-		format.cc
-		format.coverLetter
-		format.from
-		format.headers
-		format.numbered
-		format.pretty
-		format.signature
-		format.signoff
-		format.subjectprefix
-		format.suffix
-		format.thread
-		format.to
-		gc.
-		gc.aggressiveDepth
-		gc.aggressiveWindow
-		gc.auto
-		gc.autoDetach
-		gc.autopacklimit
-		gc.logExpiry
-		gc.packrefs
-		gc.pruneexpire
-		gc.reflogexpire
-		gc.reflogexpireunreachable
-		gc.rerereresolved
-		gc.rerereunresolved
-		gc.worktreePruneExpire
-		gitcvs.allbinary
-		gitcvs.commitmsgannotation
-		gitcvs.dbTableNamePrefix
-		gitcvs.dbdriver
-		gitcvs.dbname
-		gitcvs.dbpass
-		gitcvs.dbuser
-		gitcvs.enabled
-		gitcvs.logfile
-		gitcvs.usecrlfattr
-		guitool.
-		gui.blamehistoryctx
-		gui.commitmsgwidth
-		gui.copyblamethreshold
-		gui.diffcontext
-		gui.encoding
-		gui.fastcopyblame
-		gui.matchtrackingbranch
-		gui.newbranchtemplate
-		gui.pruneduringfetch
-		gui.spellingdictionary
-		gui.trustmtime
-		help.autocorrect
-		help.browser
-		help.format
-		http.lowSpeedLimit
-		http.lowSpeedTime
-		http.maxRequests
-		http.minSessions
-		http.noEPSV
-		http.postBuffer
-		http.proxy
-		http.sslCipherList
-		http.sslVersion
-		http.sslCAInfo
-		http.sslCAPath
-		http.sslCert
-		http.sslCertPasswordProtected
-		http.sslKey
-		http.sslVerify
-		http.useragent
-		i18n.commitEncoding
-		i18n.logOutputEncoding
-		imap.authMethod
-		imap.folder
-		imap.host
-		imap.pass
-		imap.port
-		imap.preformattedHTML
-		imap.sslverify
-		imap.tunnel
-		imap.user
-		init.templatedir
-		instaweb.browser
-		instaweb.httpd
-		instaweb.local
-		instaweb.modulepath
-		instaweb.port
-		interactive.singlekey
-		log.date
-		log.decorate
-		log.showroot
-		mailmap.file
-		man.
-		man.viewer
-		merge.
-		merge.conflictstyle
-		merge.log
-		merge.renameLimit
-		merge.renormalize
-		merge.stat
-		merge.tool
-		merge.verbosity
-		mergetool.
-		mergetool.keepBackup
-		mergetool.keepTemporaries
-		mergetool.prompt
-		notes.displayRef
-		notes.rewrite.
-		notes.rewrite.amend
-		notes.rewrite.rebase
-		notes.rewriteMode
-		notes.rewriteRef
-		pack.compression
-		pack.deltaCacheLimit
-		pack.deltaCacheSize
-		pack.depth
-		pack.indexVersion
-		pack.packSizeLimit
-		pack.threads
-		pack.window
-		pack.windowMemory
-		pager.
-		pretty.
-		pull.octopus
-		pull.twohead
-		push.default
-		push.followTags
-		rebase.autosquash
-		rebase.stat
-		receive.autogc
-		receive.denyCurrentBranch
-		receive.denyDeleteCurrent
-		receive.denyDeletes
-		receive.denyNonFastForwards
-		receive.fsckObjects
-		receive.unpackLimit
-		receive.updateserverinfo
-		remote.pushdefault
-		remotes.
-		repack.usedeltabaseoffset
-		rerere.autoupdate
-		rerere.enabled
-		sendemail.
-		sendemail.aliasesfile
-		sendemail.aliasfiletype
-		sendemail.bcc
-		sendemail.cc
-		sendemail.cccmd
-		sendemail.chainreplyto
-		sendemail.confirm
-		sendemail.envelopesender
-		sendemail.from
-		sendemail.identity
-		sendemail.multiedit
-		sendemail.signedoffbycc
-		sendemail.smtpdomain
-		sendemail.smtpencryption
-		sendemail.smtppass
-		sendemail.smtpserver
-		sendemail.smtpserveroption
-		sendemail.smtpserverport
-		sendemail.smtpuser
-		sendemail.suppresscc
-		sendemail.suppressfrom
-		sendemail.thread
-		sendemail.to
-		sendemail.tocmd
-		sendemail.validate
-		sendemail.smtpbatchsize
-		sendemail.smtprelogindelay
-		showbranch.default
-		status.relativePaths
-		status.showUntrackedFiles
-		status.submodulesummary
-		submodule.
-		tar.umask
-		transfer.unpackLimit
-		url.
-		user.email
-		user.name
-		user.signingkey
-		web.browser
-		branch. remote.
-	"
 }
 
 _git_remote ()
diff --git a/diff.c b/diff.c
index 136d44b45..639eb646b 100644
--- a/diff.c
+++ b/diff.c
@@ -22,6 +22,7 @@
 #include "argv-array.h"
 #include "graph.h"
 #include "packfile.h"
+#include "help.h"
 
 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
@@ -69,46 +70,37 @@ static char diff_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_FAINT_ITALIC,	/* NEW_MOVED_ALTERNATIVE_DIM */
 };
 
+static const char *color_diff_slots[] = {
+	[DIFF_CONTEXT]		      = "context",
+	[DIFF_METAINFO]		      = "meta",
+	[DIFF_FRAGINFO]		      = "frag",
+	[DIFF_FILE_OLD]		      = "old",
+	[DIFF_FILE_NEW]		      = "new",
+	[DIFF_COMMIT]		      = "commit",
+	[DIFF_WHITESPACE]	      = "whitespace",
+	[DIFF_FUNCINFO]		      = "func",
+	[DIFF_FILE_OLD_MOVED]	      = "oldMoved",
+	[DIFF_FILE_OLD_MOVED_ALT]     = "oldMovedAlternative",
+	[DIFF_FILE_OLD_MOVED_DIM]     = "oldMovedDimmed",
+	[DIFF_FILE_OLD_MOVED_ALT_DIM] = "oldMovedAlternativeDimmed",
+	[DIFF_FILE_NEW_MOVED]	      = "newMoved",
+	[DIFF_FILE_NEW_MOVED_ALT]     = "newMovedAlternative",
+	[DIFF_FILE_NEW_MOVED_DIM]     = "newMovedDimmed",
+	[DIFF_FILE_NEW_MOVED_ALT_DIM] = "newMovedAlternativeDimmed",
+};
+
 static NORETURN void die_want_option(const char *option_name)
 {
 	die(_("option '%s' requires a value"), option_name);
 }
 
+define_list_config_array_extra(color_diff_slots, {"plain"});
+
 static int parse_diff_color_slot(const char *var)
 {
-	if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
+	if (!strcasecmp(var, "plain"))
 		return DIFF_CONTEXT;
-	if (!strcasecmp(var, "meta"))
-		return DIFF_METAINFO;
-	if (!strcasecmp(var, "frag"))
-		return DIFF_FRAGINFO;
-	if (!strcasecmp(var, "old"))
-		return DIFF_FILE_OLD;
-	if (!strcasecmp(var, "new"))
-		return DIFF_FILE_NEW;
-	if (!strcasecmp(var, "commit"))
-		return DIFF_COMMIT;
-	if (!strcasecmp(var, "whitespace"))
-		return DIFF_WHITESPACE;
-	if (!strcasecmp(var, "func"))
-		return DIFF_FUNCINFO;
-	if (!strcasecmp(var, "oldmoved"))
-		return DIFF_FILE_OLD_MOVED;
-	if (!strcasecmp(var, "oldmovedalternative"))
-		return DIFF_FILE_OLD_MOVED_ALT;
-	if (!strcasecmp(var, "oldmoveddimmed"))
-		return DIFF_FILE_OLD_MOVED_DIM;
-	if (!strcasecmp(var, "oldmovedalternativedimmed"))
-		return DIFF_FILE_OLD_MOVED_ALT_DIM;
-	if (!strcasecmp(var, "newmoved"))
-		return DIFF_FILE_NEW_MOVED;
-	if (!strcasecmp(var, "newmovedalternative"))
-		return DIFF_FILE_NEW_MOVED_ALT;
-	if (!strcasecmp(var, "newmoveddimmed"))
-		return DIFF_FILE_NEW_MOVED_DIM;
-	if (!strcasecmp(var, "newmovedalternativedimmed"))
-		return DIFF_FILE_NEW_MOVED_ALT_DIM;
-	return -1;
+	return LOOKUP_CONFIG(color_diff_slots, var);
 }
 
 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
diff --git a/fsck.c b/fsck.c
index 48e7e3686..0b8b20b6c 100644
--- a/fsck.c
+++ b/fsck.c
@@ -14,6 +14,7 @@
 #include "packfile.h"
 #include "submodule-config.h"
 #include "config.h"
+#include "help.h"
 
 static struct oidset gitmodules_found = OIDSET_INIT;
 static struct oidset gitmodules_done = OIDSET_INIT;
@@ -86,37 +87,60 @@ enum fsck_msg_id {
 #undef MSG_ID
 
 #define STR(x) #x
-#define MSG_ID(id, msg_type) { STR(id), NULL, FSCK_##msg_type },
+#define MSG_ID(id, msg_type) { STR(id), NULL, NULL, FSCK_##msg_type },
 static struct {
 	const char *id_string;
 	const char *downcased;
+	const char *camelcased;
 	int msg_type;
 } msg_id_info[FSCK_MSG_MAX + 1] = {
 	FOREACH_MSG_ID(MSG_ID)
-	{ NULL, NULL, -1 }
+	{ NULL, NULL, NULL, -1 }
 };
 #undef MSG_ID
 
-static int parse_msg_id(const char *text)
+static void prepare_msg_ids(void)
 {
 	int i;
 
-	if (!msg_id_info[0].downcased) {
-		/* convert id_string to lower case, without underscores. */
-		for (i = 0; i < FSCK_MSG_MAX; i++) {
-			const char *p = msg_id_info[i].id_string;
-			int len = strlen(p);
-			char *q = xmalloc(len);
-
-			msg_id_info[i].downcased = q;
-			while (*p)
-				if (*p == '_')
-					p++;
-				else
-					*(q)++ = tolower(*(p)++);
-			*q = '\0';
+	if (msg_id_info[0].downcased)
+		return;
+
+	/* convert id_string to lower case, without underscores. */
+	for (i = 0; i < FSCK_MSG_MAX; i++) {
+		const char *p = msg_id_info[i].id_string;
+		int len = strlen(p);
+		char *q = xmalloc(len);
+
+		msg_id_info[i].downcased = q;
+		while (*p)
+			if (*p == '_')
+				p++;
+			else
+				*(q)++ = tolower(*(p)++);
+		*q = '\0';
+
+		p = msg_id_info[i].id_string;
+		q = xmalloc(len);
+		msg_id_info[i].camelcased = q;
+		while (*p) {
+			if (*p == '_') {
+				p++;
+				if (*p)
+					*q++ = *p++;
+			} else {
+				*q++ = tolower(*p++);
+			}
 		}
+		*q = '\0';
 	}
+}
+
+static int parse_msg_id(const char *text)
+{
+	int i;
+
+	prepare_msg_ids();
 
 	for (i = 0; i < FSCK_MSG_MAX; i++)
 		if (!strcmp(text, msg_id_info[i].downcased))
@@ -125,6 +149,16 @@ static int parse_msg_id(const char *text)
 	return -1;
 }
 
+void list_config_fsck_msg_ids(struct string_list *list, const char *prefix)
+{
+	int i;
+
+	prepare_msg_ids();
+
+	for (i = 0; i < FSCK_MSG_MAX; i++)
+		list_config_item(list, prefix, msg_id_info[i].camelcased);
+}
+
 static int fsck_msg_type(enum fsck_msg_id msg_id,
 	struct fsck_options *options)
 {
diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh
index 8d6d8b45c..c4124acbe 100755
--- a/generate-cmdlist.sh
+++ b/generate-cmdlist.sh
@@ -76,6 +76,23 @@ print_command_list () {
 	echo "};"
 }
 
+print_config_list () {
+	cat <<EOF
+static const char *config_name_list[] = {
+EOF
+	grep '^[a-zA-Z].*\..*::$' Documentation/config.txt |
+	sed '/deprecated/d; s/::$//; s/,  */\n/g' |
+	sort |
+	while read line
+	do
+		echo "	\"$line\","
+	done
+	cat <<EOF
+	NULL,
+};
+EOF
+}
+
 echo "/* Automatically generated by generate-cmdlist.sh */
 struct cmdname_help {
 	const char *name;
@@ -88,3 +105,5 @@ echo
 define_category_names "$1"
 echo
 print_command_list "$1"
+echo
+print_config_list
diff --git a/grep.c b/grep.c
index 45ec7e636..7c1b8e2e8 100644
--- a/grep.c
+++ b/grep.c
@@ -7,12 +7,24 @@
 #include "diffcore.h"
 #include "commit.h"
 #include "quote.h"
+#include "help.h"
 
 static int grep_source_load(struct grep_source *gs);
 static int grep_source_is_binary(struct grep_source *gs);
 
 static struct grep_opt grep_defaults;
 
+static const char *color_grep_slots[] = {
+	[GREP_COLOR_CONTEXT]	    = "context",
+	[GREP_COLOR_FILENAME]	    = "filename",
+	[GREP_COLOR_FUNCTION]	    = "function",
+	[GREP_COLOR_LINENO]	    = "lineNumber",
+	[GREP_COLOR_MATCH_CONTEXT]  = "matchContext",
+	[GREP_COLOR_MATCH_SELECTED] = "matchSelected",
+	[GREP_COLOR_SELECTED]	    = "selected",
+	[GREP_COLOR_SEP]	    = "separator",
+};
+
 static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 {
 	fwrite(buf, size, 1, stdout);
@@ -42,14 +54,14 @@ void init_grep_defaults(void)
 	opt->pathname = 1;
 	opt->max_depth = -1;
 	opt->pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED;
-	color_set(opt->color_context, "");
-	color_set(opt->color_filename, "");
-	color_set(opt->color_function, "");
-	color_set(opt->color_lineno, "");
-	color_set(opt->color_match_context, GIT_COLOR_BOLD_RED);
-	color_set(opt->color_match_selected, GIT_COLOR_BOLD_RED);
-	color_set(opt->color_selected, "");
-	color_set(opt->color_sep, GIT_COLOR_CYAN);
+	color_set(opt->colors[GREP_COLOR_CONTEXT], "");
+	color_set(opt->colors[GREP_COLOR_FILENAME], "");
+	color_set(opt->colors[GREP_COLOR_FUNCTION], "");
+	color_set(opt->colors[GREP_COLOR_LINENO], "");
+	color_set(opt->colors[GREP_COLOR_MATCH_CONTEXT], GIT_COLOR_BOLD_RED);
+	color_set(opt->colors[GREP_COLOR_MATCH_SELECTED], GIT_COLOR_BOLD_RED);
+	color_set(opt->colors[GREP_COLOR_SELECTED], "");
+	color_set(opt->colors[GREP_COLOR_SEP], GIT_COLOR_CYAN);
 	opt->color = -1;
 	opt->output = std_output;
 }
@@ -69,6 +81,8 @@ static int parse_pattern_type_arg(const char *opt, const char *arg)
 	die("bad %s argument: %s", opt, arg);
 }
 
+define_list_config_array_extra(color_grep_slots, {"match"});
+
 /*
  * Read the configuration file once and store it in
  * the grep_defaults template.
@@ -76,7 +90,7 @@ static int parse_pattern_type_arg(const char *opt, const char *arg)
 int grep_config(const char *var, const char *value, void *cb)
 {
 	struct grep_opt *opt = &grep_defaults;
-	char *color = NULL;
+	const char *slot;
 
 	if (userdiff_config(var, value) < 0)
 		return -1;
@@ -103,32 +117,18 @@ int grep_config(const char *var, const char *value, void *cb)
 
 	if (!strcmp(var, "color.grep"))
 		opt->color = git_config_colorbool(var, value);
-	else if (!strcmp(var, "color.grep.context"))
-		color = opt->color_context;
-	else if (!strcmp(var, "color.grep.filename"))
-		color = opt->color_filename;
-	else if (!strcmp(var, "color.grep.function"))
-		color = opt->color_function;
-	else if (!strcmp(var, "color.grep.linenumber"))
-		color = opt->color_lineno;
-	else if (!strcmp(var, "color.grep.matchcontext"))
-		color = opt->color_match_context;
-	else if (!strcmp(var, "color.grep.matchselected"))
-		color = opt->color_match_selected;
-	else if (!strcmp(var, "color.grep.selected"))
-		color = opt->color_selected;
-	else if (!strcmp(var, "color.grep.separator"))
-		color = opt->color_sep;
-	else if (!strcmp(var, "color.grep.match")) {
-		int rc = 0;
-		if (!value)
-			return config_error_nonbool(var);
-		rc |= color_parse(value, opt->color_match_context);
-		rc |= color_parse(value, opt->color_match_selected);
-		return rc;
-	}
-
-	if (color) {
+	if (!strcmp(var, "color.grep.match")) {
+		if (grep_config("color.grep.matchcontext", value, cb) < 0)
+			return -1;
+		if (grep_config("color.grep.matchselected", value, cb) < 0)
+			return -1;
+	} else if (skip_prefix(var, "color.grep.", &slot)) {
+		int i = LOOKUP_CONFIG(color_grep_slots, slot);
+		char *color;
+
+		if (i < 0)
+			return -1;
+		color = opt->colors[i];
 		if (!value)
 			return config_error_nonbool(var);
 		return color_parse(value, color);
@@ -144,6 +144,7 @@ int grep_config(const char *var, const char *value, void *cb)
 void grep_init(struct grep_opt *opt, const char *prefix)
 {
 	struct grep_opt *def = &grep_defaults;
+	int i;
 
 	memset(opt, 0, sizeof(*opt));
 	opt->prefix = prefix;
@@ -160,14 +161,8 @@ void grep_init(struct grep_opt *opt, const char *prefix)
 	opt->relative = def->relative;
 	opt->output = def->output;
 
-	color_set(opt->color_context, def->color_context);
-	color_set(opt->color_filename, def->color_filename);
-	color_set(opt->color_function, def->color_function);
-	color_set(opt->color_lineno, def->color_lineno);
-	color_set(opt->color_match_context, def->color_match_context);
-	color_set(opt->color_match_selected, def->color_match_selected);
-	color_set(opt->color_selected, def->color_selected);
-	color_set(opt->color_sep, def->color_sep);
+	for (i = 0; i < NR_GREP_COLORS; i++)
+		color_set(opt->colors[i], def->colors[i]);
 }
 
 static void grep_set_pattern_type_option(enum grep_pattern_type pattern_type, struct grep_opt *opt)
@@ -1098,12 +1093,12 @@ static void output_sep(struct grep_opt *opt, char sign)
 	if (opt->null_following_name)
 		opt->output(opt, "\0", 1);
 	else
-		output_color(opt, &sign, 1, opt->color_sep);
+		output_color(opt, &sign, 1, opt->colors[GREP_COLOR_SEP]);
 }
 
 static void show_name(struct grep_opt *opt, const char *name)
 {
-	output_color(opt, name, strlen(name), opt->color_filename);
+	output_color(opt, name, strlen(name), opt->colors[GREP_COLOR_FILENAME]);
 	opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 }
 
@@ -1370,28 +1365,28 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 	} else if (opt->pre_context || opt->post_context || opt->funcbody) {
 		if (opt->last_shown == 0) {
 			if (opt->show_hunk_mark) {
-				output_color(opt, "--", 2, opt->color_sep);
+				output_color(opt, "--", 2, opt->colors[GREP_COLOR_SEP]);
 				opt->output(opt, "\n", 1);
 			}
 		} else if (lno > opt->last_shown + 1) {
-			output_color(opt, "--", 2, opt->color_sep);
+			output_color(opt, "--", 2, opt->colors[GREP_COLOR_SEP]);
 			opt->output(opt, "\n", 1);
 		}
 	}
 	if (opt->heading && opt->last_shown == 0) {
-		output_color(opt, name, strlen(name), opt->color_filename);
+		output_color(opt, name, strlen(name), opt->colors[GREP_COLOR_FILENAME]);
 		opt->output(opt, "\n", 1);
 	}
 	opt->last_shown = lno;
 
 	if (!opt->heading && opt->pathname) {
-		output_color(opt, name, strlen(name), opt->color_filename);
+		output_color(opt, name, strlen(name), opt->colors[GREP_COLOR_FILENAME]);
 		output_sep(opt, sign);
 	}
 	if (opt->linenum) {
 		char buf[32];
 		xsnprintf(buf, sizeof(buf), "%d", lno);
-		output_color(opt, buf, strlen(buf), opt->color_lineno);
+		output_color(opt, buf, strlen(buf), opt->colors[GREP_COLOR_LINENO]);
 		output_sep(opt, sign);
 	}
 	if (opt->color) {
@@ -1401,15 +1396,15 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 		int eflags = 0;
 
 		if (sign == ':')
-			match_color = opt->color_match_selected;
+			match_color = opt->colors[GREP_COLOR_MATCH_SELECTED];
 		else
-			match_color = opt->color_match_context;
+			match_color = opt->colors[GREP_COLOR_MATCH_CONTEXT];
 		if (sign == ':')
-			line_color = opt->color_selected;
+			line_color = opt->colors[GREP_COLOR_SELECTED];
 		else if (sign == '-')
-			line_color = opt->color_context;
+			line_color = opt->colors[GREP_COLOR_CONTEXT];
 		else if (sign == '=')
-			line_color = opt->color_function;
+			line_color = opt->colors[GREP_COLOR_FUNCTION];
 		*eol = '\0';
 		while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 			if (match.rm_so == match.rm_eo)
@@ -1816,7 +1811,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 			if (binary_match_only) {
 				opt->output(opt, "Binary file ", 12);
 				output_color(opt, gs->name, strlen(gs->name),
-					     opt->color_filename);
+					     opt->colors[GREP_COLOR_FILENAME]);
 				opt->output(opt, " matches\n", 9);
 				return 1;
 			}
@@ -1890,7 +1885,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 		char buf[32];
 		if (opt->pathname) {
 			output_color(opt, gs->name, strlen(gs->name),
-				     opt->color_filename);
+				     opt->colors[GREP_COLOR_FILENAME]);
 			output_sep(opt, ':');
 		}
 		xsnprintf(buf, sizeof(buf), "%u\n", count);
diff --git a/grep.h b/grep.h
index 399381c90..ed25be271 100644
--- a/grep.h
+++ b/grep.h
@@ -62,6 +62,18 @@ enum grep_header_field {
 	GREP_HEADER_FIELD_MAX
 };
 
+enum grep_color {
+	GREP_COLOR_CONTEXT,
+	GREP_COLOR_FILENAME,
+	GREP_COLOR_FUNCTION,
+	GREP_COLOR_LINENO,
+	GREP_COLOR_MATCH_CONTEXT,
+	GREP_COLOR_MATCH_SELECTED,
+	GREP_COLOR_SELECTED,
+	GREP_COLOR_SEP,
+	NR_GREP_COLORS
+};
+
 struct grep_pat {
 	struct grep_pat *next;
 	const char *origin;
@@ -155,14 +167,7 @@ struct grep_opt {
 	int funcbody;
 	int extended_regexp_option;
 	int pattern_type_option;
-	char color_context[COLOR_MAXLEN];
-	char color_filename[COLOR_MAXLEN];
-	char color_function[COLOR_MAXLEN];
-	char color_lineno[COLOR_MAXLEN];
-	char color_match_context[COLOR_MAXLEN];
-	char color_match_selected[COLOR_MAXLEN];
-	char color_selected[COLOR_MAXLEN];
-	char color_sep[COLOR_MAXLEN];
+	char colors[NR_GREP_COLORS][COLOR_MAXLEN];
 	unsigned pre_context;
 	unsigned post_context;
 	unsigned last_shown;
diff --git a/help.c b/help.c
index dd35fcc13..3ebf0568d 100644
--- a/help.c
+++ b/help.c
@@ -409,6 +409,90 @@ void list_common_guides_help(void)
 	putchar('\n');
 }
 
+struct slot_expansion {
+	const char *prefix;
+	const char *placeholder;
+	void (*fn)(struct string_list *list, const char *prefix);
+	int found;
+};
+
+void list_config_help(int for_human)
+{
+	struct slot_expansion slot_expansions[] = {
+		{ "advice", "*", list_config_advices },
+		{ "color.branch", "<slot>", list_config_color_branch_slots },
+		{ "color.decorate", "<slot>", list_config_color_decorate_slots },
+		{ "color.diff", "<slot>", list_config_color_diff_slots },
+		{ "color.grep", "<slot>", list_config_color_grep_slots },
+		{ "color.interactive", "<slot>", list_config_color_interactive_slots },
+		{ "color.status", "<slot>", list_config_color_status_slots },
+		{ "fsck", "<msg-id>", list_config_fsck_msg_ids },
+		{ "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
+		{ NULL, NULL, NULL }
+	};
+	const char **p;
+	struct slot_expansion *e;
+	struct string_list keys = STRING_LIST_INIT_DUP;
+	int i;
+
+	for (p = config_name_list; *p; p++) {
+		const char *var = *p;
+		struct strbuf sb = STRBUF_INIT;
+
+		for (e = slot_expansions; e->prefix; e++) {
+
+			strbuf_reset(&sb);
+			strbuf_addf(&sb, "%s.%s", e->prefix, e->placeholder);
+			if (!strcasecmp(var, sb.buf)) {
+				e->fn(&keys, e->prefix);
+				e->found++;
+				break;
+			}
+		}
+		strbuf_release(&sb);
+		if (!e->prefix)
+			string_list_append(&keys, var);
+	}
+
+	for (e = slot_expansions; e->prefix; e++)
+		if (!e->found)
+			BUG("slot_expansion %s.%s is not used",
+			    e->prefix, e->placeholder);
+
+	string_list_sort(&keys);
+	for (i = 0; i < keys.nr; i++) {
+		const char *var = keys.items[i].string;
+		const char *wildcard, *tag, *cut;
+
+		if (for_human) {
+			puts(var);
+			continue;
+		}
+
+		wildcard = strchr(var, '*');
+		tag = strchr(var, '<');
+
+		if (!wildcard && !tag) {
+			puts(var);
+			continue;
+		}
+
+		if (wildcard && !tag)
+			cut = wildcard;
+		else if (!wildcard && tag)
+			cut = tag;
+		else
+			cut = wildcard < tag ? wildcard : tag;
+
+		/*
+		 * We may produce duplicates, but that's up to
+		 * git-completion.bash to handle
+		 */
+		printf("%.*s\n", (int)(cut - var), var);
+	}
+	string_list_clear(&keys, 0);
+}
+
 void list_all_cmds_help(void)
 {
 	print_cmd_by_category(main_categories);
diff --git a/help.h b/help.h
index 3b38292a1..f8b15323a 100644
--- a/help.h
+++ b/help.h
@@ -1,7 +1,8 @@
 #ifndef HELP_H
 #define HELP_H
 
-struct string_list;
+#include "string-list.h"
+#include "strbuf.h"
 
 struct cmdnames {
 	int alloc;
@@ -21,6 +22,7 @@ static inline void mput_char(char c, unsigned int num)
 extern void list_common_cmds_help(void);
 extern void list_all_cmds_help(void);
 extern void list_common_guides_help(void);
+extern void list_config_help(int for_human);
 
 extern void list_all_main_cmds(struct string_list *list);
 extern void list_all_other_cmds(struct string_list *list);
@@ -42,4 +44,45 @@ extern void list_commands(unsigned int colopts, struct cmdnames *main_cmds, stru
  * ref to the command, to give suggested "correct" refs.
  */
 extern void help_unknown_ref(const char *ref, const char *cmd, const char *error);
+
+static inline void list_config_item(struct string_list *list,
+				    const char *prefix,
+				    const char *str)
+{
+	string_list_append_nodup(list, xstrfmt("%s.%s", prefix, str));
+}
+
+#define define_list_config_array(array)					\
+void list_config_##array(struct string_list *list, const char *prefix)	\
+{									\
+	int i;								\
+	for (i = 0; i < ARRAY_SIZE(array); i++)				\
+		if (array[i])						\
+			list_config_item(list, prefix, array[i]);	\
+}									\
+struct string_list
+
+#define define_list_config_array_extra(array, values)			\
+void list_config_##array(struct string_list *list, const char *prefix)	\
+{									\
+	int i;								\
+	static const char *extra[] = values;				\
+	for (i = 0; i < ARRAY_SIZE(extra); i++)				\
+		list_config_item(list, prefix, extra[i]);		\
+	for (i = 0; i < ARRAY_SIZE(array); i++)				\
+		if (array[i])						\
+			list_config_item(list, prefix, array[i]);	\
+}									\
+struct string_list
+
+/* These are actually scattered over many C files */
+void list_config_advices(struct string_list *list, const char *prefix);
+void list_config_color_branch_slots(struct string_list *list, const char *prefix);
+void list_config_color_decorate_slots(struct string_list *list, const char *prefix);
+void list_config_color_diff_slots(struct string_list *list, const char *prefix);
+void list_config_color_grep_slots(struct string_list *list, const char *prefix);
+void list_config_color_interactive_slots(struct string_list *list, const char *prefix);
+void list_config_color_status_slots(struct string_list *list, const char *prefix);
+void list_config_fsck_msg_ids(struct string_list *list, const char *prefix);
+
 #endif /* HELP_H */
diff --git a/log-tree.c b/log-tree.c
index 0b97de5e8..d3a43e29c 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -12,6 +12,7 @@
 #include "gpg-interface.h"
 #include "sequencer.h"
 #include "line-log.h"
+#include "help.h"
 
 static struct decoration name_decoration = { "object names" };
 static int decoration_loaded;
@@ -27,6 +28,15 @@ static char decoration_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_BOLD_BLUE,	/* GRAFTED */
 };
 
+static const char *color_decorate_slots[] = {
+	[DECORATION_REF_LOCAL]	= "branch",
+	[DECORATION_REF_REMOTE] = "remoteBranch",
+	[DECORATION_REF_TAG]	= "tag",
+	[DECORATION_REF_STASH]	= "stash",
+	[DECORATION_REF_HEAD]	= "HEAD",
+	[DECORATION_GRAFTED]	= "grafted",
+};
+
 static const char *decorate_get_color(int decorate_use_color, enum decoration_type ix)
 {
 	if (want_color(decorate_use_color))
@@ -34,34 +44,11 @@ static const char *decorate_get_color(int decorate_use_color, enum decoration_ty
 	return "";
 }
 
-static int parse_decorate_color_slot(const char *slot)
-{
-	/*
-	 * We're comparing with 'ignore-case' on
-	 * (because config.c sets them all tolower),
-	 * but let's match the letters in the literal
-	 * string values here with how they are
-	 * documented in Documentation/config.txt, for
-	 * consistency.
-	 *
-	 * We love being consistent, don't we?
-	 */
-	if (!strcasecmp(slot, "branch"))
-		return DECORATION_REF_LOCAL;
-	if (!strcasecmp(slot, "remoteBranch"))
-		return DECORATION_REF_REMOTE;
-	if (!strcasecmp(slot, "tag"))
-		return DECORATION_REF_TAG;
-	if (!strcasecmp(slot, "stash"))
-		return DECORATION_REF_STASH;
-	if (!strcasecmp(slot, "HEAD"))
-		return DECORATION_REF_HEAD;
-	return -1;
-}
+define_list_config_array(color_decorate_slots);
 
 int parse_decorate_color_config(const char *var, const char *slot_name, const char *value)
 {
-	int slot = parse_decorate_color_slot(slot_name);
+	int slot = LOOKUP_CONFIG(color_decorate_slots, slot_name);
 	if (slot < 0)
 		return 0;
 	if (!value)
diff --git a/t/t4254-am-corrupt.sh b/t/t4254-am-corrupt.sh
index 168739c72..fd3bdbfe2 100755
--- a/t/t4254-am-corrupt.sh
+++ b/t/t4254-am-corrupt.sh
@@ -25,7 +25,7 @@ test_expect_success setup '
 #   fatal: unable to write file '(null)' mode 100644: Bad address
 # Also, it had the unwanted side-effect of deleting f.
 test_expect_success 'try to apply corrupted patch' '
-	test_must_fail git am bad-patch.diff 2>actual
+	test_must_fail git -c advice.amWorkDir=false am bad-patch.diff 2>actual
 '
 
 test_expect_success 'compare diagnostic; ensure file is still here' '