add amend mode

doc/tigrc.5.adoc

@@ -617,6 +617,9 @@ bind generic G none
 # User-defined external command to amend the last commit
 bind status + !git commit --amend
 
+# Toggle amend mode in the status or stage view
+bind status a status-amend
+
 # User-defined internal command that reloads ~/.tigrc
 bind generic S :source ~/.tigrc
 
@@ -922,6 +925,7 @@ View-specific actions
 [frame="none",grid="none",cols="25<m,75<"]
 |=============================================================================
 |status-update           |Stage/unstage chunk or file changes
+|status-amend            |Toggle amend mode
 |status-revert           |Revert chunk or file changes
 |status-merge            |Merge file using external tool
 |stage-update-line       |Stage/unstage single line

include/tig/repo.h

@@ -30,7 +30,8 @@ typedef char repo_str[SIZEOF_STR];
 	_(repo_str, git_dir) \
 	_(repo_str, worktree) \
 	_(repo_str, exec_dir) \
-	_(bool,     is_inside_work_tree)
+	_(bool,     is_inside_work_tree) \
+	_(bool,     amend_mode)
 
 #define REPO_INFO_FIELDS(type, name)	type name;
 
@@ -51,6 +52,9 @@ struct index_diff {
 
 bool index_diff(struct index_diff *diff, bool untracked, bool count_all);
 bool update_index(void);
+const char *repo_staged_parent(void);
+bool repo_amend_mode_enabled(void);
+bool repo_toggle_amend_mode(void);
 
 #endif
 /* vim: set ts=8 sw=8 noexpandtab: */

include/tig/request.h

@@ -41,6 +41,7 @@
 	\
 	REQ_GROUP("View-specific actions") \
 	REQ_(STATUS_UPDATE,	"Stage/unstage chunk or file changes"), \
+	REQ_(STATUS_AMEND,	"Toggle amend mode"), \
 	REQ_(STATUS_REVERT,	"Revert chunk or file changes"), \
 	REQ_(STATUS_MERGE,	"Merge file using external tool"), \
 	REQ_(STAGE_UPDATE_LINE,	"Stage/unstage single line"), \

src/main.c

@@ -211,7 +211,8 @@ main_add_changes(struct view *view, struct main_state *state, const char *parent
 
 	return main_add_changes_commit(view, LINE_STAT_UNTRACKED, untracked_parent, "Untracked changes")
 	    && main_add_changes_commit(view, LINE_STAT_UNSTAGED, unstaged_parent, "Unstaged changes")
-	    && main_add_changes_commit(view, LINE_STAT_STAGED, staged_parent, "Staged changes");
+	    && main_add_changes_commit(view, LINE_STAT_STAGED, staged_parent,
+	     repo_amend_mode_enabled() ? "Amend changes" : "Staged changes");
 }
 
 static bool

src/prompt.c

@@ -1125,6 +1125,31 @@ run_prompt_command(struct view *view, const char *argv[])
 	return REQ_NONE;
 }
 
+static bool
+run_request_should_amend(const char **argv)
+{
+	return repo_amend_mode_enabled() &&
+	       argv && argv[0] && argv[1] &&
+	       !strcmp(argv[0], "git") &&
+	       !strcmp(argv[1], "commit") &&
+	       !argv_contains(argv, "--amend");
+}
+
+static bool
+run_request_add_amend(const char ***dst_argv, const char **src_argv)
+{
+	size_t i;
+
+	for (i = 0; src_argv[i]; i++) {
+		if (!argv_append(dst_argv, src_argv[i]))
+			return false;
+		if (i == 1 && !argv_append(dst_argv, "--amend"))
+			return false;
+	}
+
+	return true;
+}
+
 enum request
 exec_run_request(struct view *view, struct run_request *req)
 {
@@ -1146,6 +1171,23 @@ exec_run_request(struct view *view, struct run_request *req)
 		return REQ_NONE;
 	}
 
+	if (run_request_should_amend(argv)) {
+		const char **amend_argv = NULL;
+
+		if (!run_request_add_amend(&amend_argv, argv)) {
+			argv_free(argv);
+			free(argv);
+			argv_free(amend_argv);
+			free(amend_argv);
+			report("Failed to prepare amend commit command");
+			return REQ_NONE;
+		}
+
+		argv_free(argv);
+		free(argv);
+		argv = amend_argv;
+	}
+
 	if (req->flags.internal) {
 		request = run_prompt_command(view, argv);
 

src/repo.c

@@ -16,6 +16,8 @@
 #include "tig/io.h"
 #include "tig/refdb.h"
 #include "tig/git.h"
+#include "tig/display.h"
+#include "tig/status.h"
 
 #define REPO_INFO_GIT_DIR	"--git-dir"
 #define REPO_INFO_WORK_TREE	"--is-inside-work-tree"
@@ -131,6 +133,31 @@ load_repo_head(void)
 
 struct repo_info repo;
 
+const char *
+repo_staged_parent(void)
+{
+	return repo.amend_mode ? "HEAD^" : "HEAD";
+}
+
+bool
+repo_amend_mode_enabled(void)
+{
+	return repo.amend_mode;
+}
+
+bool
+repo_toggle_amend_mode(void)
+{
+	if (!repo.amend_mode && is_initial_commit()) {
+		report("Amend mode requires an existing commit");
+		return false;
+	}
+
+	repo.amend_mode = !repo.amend_mode;
+	report("Amend mode %s", repo.amend_mode ? "enabled" : "disabled");
+	return true;
+}
+
 /*
  * Git index utils.
  */
@@ -154,6 +181,7 @@ index_diff(struct index_diff *diff, bool untracked, bool count_all)
 	const char *status_argv[] = {
 		"git", "status", "--porcelain", "-z", untracked_arg, NULL
 	};
+	const char *staged_parent = repo_staged_parent();
 	struct io io;
 	struct buffer buf;
 	bool ok = true;
@@ -185,6 +213,41 @@ index_diff(struct index_diff *diff, bool untracked, bool count_all)
 		ok = false;
 
 	io_done(&io);
+	if (!ok || !repo.amend_mode || is_initial_commit())
+		return ok;
+
+	{
+		const char *diff_index_argv[] = {
+			"git", "diff-index", "--cached", "--diff-filter=ACDMRTXB",
+			"-z", staged_parent, "--", NULL
+		};
+		int staged = 0;
+		struct status parsed = {0};
+
+		if (!io_run(&io, IO_RD, repo.exec_dir, NULL, diff_index_argv))
+			return false;
+
+		while (io_get(&io, &buf, 0, true) && (ok = buf.size > 3)) {
+			if (!status_get_diff(&parsed, buf.data, buf.size)) {
+				ok = false;
+				break;
+			}
+			staged++;
+			if (parsed.status == 'R' || parsed.status == 'C')
+				io_get(&io, &buf, 0, true);
+			if (!io_get(&io, &buf, 0, true))
+				break;
+			if (!count_all && staged && diff->unstaged &&
+			    (!untracked || diff->untracked))
+				break;
+		}
+
+		if (io_error(&io))
+			ok = false;
+		io_done(&io);
+		diff->staged = staged;
+	}
+
 	return ok;
 }
 

src/stage.c

@@ -452,11 +452,14 @@ find_deleted_line_in_head(struct view *view, struct line *line) {
 	unsigned long line_number_in_head, line_number = 0;
 	long bias_by_staged_changes = 0;
 	char buf[SIZEOF_STR] = "";
+	const char *staged_parent = repo_staged_parent();
 	char file_in_head_pathspec[sizeof("HEAD:") + SIZEOF_STR],
 		file_in_index_pathspec[sizeof(":") + SIZEOF_STR];
 	const char *file_in_head = NULL;
 	const char *ls_tree_argv[] = {
-		"git", "ls-tree", "-z", "HEAD", view->env->file, NULL
+		"git", "ls-tree", "-z",
+		stage_line_type == LINE_STAT_STAGED ? staged_parent : "HEAD",
+		view->env->file, NULL
 	};
 	const char *diff_argv[] = {
 		"git", "diff", file_in_head_pathspec, file_in_index_pathspec,
@@ -473,7 +476,9 @@ find_deleted_line_in_head(struct view *view, struct line *line) {
 	} else { // The file might might be renamed in the index. Find its old name.
 		const char *diff_index_argv[] = {
 			"git", "diff-index", "--cached", "-C",
-			"--diff-filter=ACR", "-z", "HEAD", NULL
+			"--diff-filter=ACR", "-z",
+			stage_line_type == LINE_STAT_STAGED ? staged_parent : "HEAD",
+			NULL
 		};
 		if (!io_run(&io, IO_RD, repo.exec_dir, NULL, diff_index_argv) || io.status)
 			return false;
@@ -565,6 +570,12 @@ stage_request(struct view *view, enum request request, struct line *line)
 			return REQ_NONE;
 		break;
 
+	case REQ_STATUS_AMEND:
+		if (!repo_toggle_amend_mode())
+			return REQ_NONE;
+		load_repo_head();
+		break;
+
 	case REQ_STATUS_REVERT:
 		if (!stage_revert(view, line))
 			return REQ_NONE;
@@ -655,7 +666,8 @@ stage_request(struct view *view, enum request request, struct line *line)
 
 		view->env->ref[0] = 0;
 		if (find_deleted_line_in_head(view, line))
-			string_copy(view->env->ref, "HEAD");
+			string_copy(view->env->ref,
+			 stage_line_type == LINE_STAT_STAGED ? repo_staged_parent() : "HEAD");
 		else
 			view->env->goto_lineno = diff_get_lineno(view, line, false);
 		if (view->env->goto_lineno > 0)
@@ -698,7 +710,8 @@ stage_request(struct view *view, enum request request, struct line *line)
 static void
 stage_select(struct view *view, struct line *line)
 {
-	const char *changes_msg = stage_line_type == LINE_STAT_STAGED ? "Staged changes"
+	const char *changes_msg = stage_line_type == LINE_STAT_STAGED
+				? repo_amend_mode_enabled() ? "Amend changes" : "Staged changes"
 				: stage_line_type == LINE_STAT_UNSTAGED ? "Unstaged changes"
 				: NULL;
 
@@ -713,9 +726,11 @@ stage_open(struct view *view, enum open_flags flags)
 			stage_status.new.name)
 	};
 	const char *index_show_argv[] = {
-		GIT_DIFF_STAGED(encoding_arg, diff_context_arg(), diff_prefix_arg(),
-			ignore_space_arg(), word_diff_arg(), stage_status.old.name,
-			stage_status.new.name)
+		"git", "diff-index", encoding_arg, "--textconv", "--patch-with-stat", "-C",
+			"--cached", "--diff-filter=ACDMRTXB", DIFF_ARGS, "%(cmdlineargs)",
+			diff_context_arg(), diff_prefix_arg(), ignore_space_arg(),
+			word_diff_arg(), repo_staged_parent(), "--",
+			stage_status.old.name, stage_status.new.name, NULL
 	};
 	const char *files_show_argv[] = {
 		GIT_DIFF_UNSTAGED(encoding_arg, diff_context_arg(), diff_prefix_arg(),

src/status.c

@@ -185,7 +185,6 @@ status_run(struct view *view, const char *argv[], char status, enum line_type ty
 	return true;
 }
 
-static const char *status_diff_index_argv[] = { GIT_DIFF_STAGED_FILES("-z") };
 static const char *status_diff_files_argv[] = { GIT_DIFF_UNSTAGED_FILES("-z") };
 
 static const char *status_list_other_argv[] = {
@@ -352,6 +351,14 @@ status_update_onbranch(void)
 		if (!string_format(status_onbranch, fmt,
 				   prefix, head, tracking_info))
 			string_copy(status_onbranch, repo.head);
+		if (repo_amend_mode_enabled()) {
+			char amend_status[SIZEOF_STR];
+
+			if (string_nformat(amend_status, sizeof(amend_status), NULL,
+			     "%s [amend]", status_onbranch)) {
+				string_copy(status_onbranch, amend_status);
+			}
+		}
 		return;
 	}
 
@@ -379,6 +386,10 @@ status_read_untracked(struct view *view)
 static enum status_code
 status_open(struct view *view, enum open_flags flags)
 {
+	const char *status_diff_index_argv[] = {
+		"git", "diff-index", "-z", "%(cmdlineargs)", "--diff-filter=ACDMRTXB",
+		"-C", "--cached", repo_staged_parent(), "--", NULL
+	};
 	const char **staged_argv = is_initial_commit() ?
 		status_list_no_head_argv : status_diff_index_argv;
 	char staged_status = staged_argv == status_list_no_head_argv ? 'A' : 0;
@@ -423,7 +434,9 @@ status_get_column_data(struct view *view, const struct line *line, struct view_c
 		switch (line->type) {
 		case LINE_STAT_STAGED:
 			type = LINE_SECTION;
-			text = "Changes to be committed:";
+			text = repo_amend_mode_enabled() ?
+				"Changes to be amended:" :
+				"Changes to be committed:";
 			break;
 
 		case LINE_STAT_UNSTAGED:
@@ -722,6 +735,12 @@ status_request(struct view *view, enum request request, struct line *line)
 			return REQ_NONE;
 		break;
 
+	case REQ_STATUS_AMEND:
+		if (!repo_toggle_amend_mode())
+			return REQ_NONE;
+		load_repo_head();
+		break;
+
 	case REQ_STATUS_REVERT:
 		if (!status_revert(status, line->type, status_has_none(view, line)))
 			return REQ_NONE;
@@ -791,9 +810,13 @@ status_stage_info_(char *buf, size_t bufsize,
 	switch (type) {
 	case LINE_STAT_STAGED:
 		if (status && status->status)
-			info = "Staged changes to %s";
+			info = repo_amend_mode_enabled() ?
+				"Amend changes to %s" :
+				"Staged changes to %s";
 		else
-			info = "Staged changes";
+			info = repo_amend_mode_enabled() ?
+				"Amend changes" :
+				"Staged changes";
 		break;
 
 	case LINE_STAT_UNSTAGED:
@@ -831,15 +854,21 @@ status_select(struct view *view, struct line *line)
 
 	switch (line->type) {
 	case LINE_STAT_STAGED:
-		text = "Press %s to unstage %s for commit";
+		text = repo_amend_mode_enabled() ?
+			"Press %s to unstage %s from amend commit" :
+			"Press %s to unstage %s for commit";
 		break;
 
 	case LINE_STAT_UNSTAGED:
-		text = "Press %s to stage %s for commit";
+		text = repo_amend_mode_enabled() ?
+			"Press %s to stage %s for amend commit" :
+			"Press %s to stage %s for commit";
 		break;
 
 	case LINE_STAT_UNTRACKED:
-		text = "Press %s to stage %s for addition";
+		text = repo_amend_mode_enabled() ?
+			"Press %s to stage %s for amend commit" :
+			"Press %s to stage %s for addition";
 		break;
 
 	default: