[PATCH v2] launch_editor(): indicate that Git waits for user input

[lars.schneider@autodesk.com]

From: Junio C Hamano <gitster@pobox.com>

When a graphical GIT_EDITOR is spawned by a Git command that opens
and waits for user input (e.g. "git rebase -i"), then the editor window
might be obscured by other windows. The user may be left staring at the
original Git terminal window without even realizing that s/he needs to
interact with another window before Git can proceed. To this user Git
appears hanging.

Show a message in the original terminal and get rid of it when the
editor returns.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
---

Junio posted the original version of this patch [1] as response to my RFC [2].
I took Junio's patch and slightly changed the commit message as well as the
message printed to the user after GIT_EDITOR is invoked [3].

Thanks,
Lars


[1] https://public-inbox.org/git/xmqqr2syvjxb.fsf@gitster.mtv.corp.google.com/
[2] https://public-inbox.org/git/274B4850-2EB7-4BFA-A42C-25A573254969@gmail.com/
[3] https://public-inbox.org/git/DAEC36C7-AE09-4C9B-ACC4-07F2C5F2B97F@gmail.com/

Notes:
    Base Ref: master
    Web-Diff: https://github.com/larsxschneider/git/commit/6fd6d8e682
    Checkout: git fetch https://github.com/larsxschneider/git editor-v2 && git checkout 6fd6d8e682


 editor.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/editor.c b/editor.c
index 7519edecdc..23db92d8c6 100644
--- a/editor.c
+++ b/editor.c
@@ -40,6 +40,32 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
 		const char *args[] = { editor, real_path(path), NULL };
 		struct child_process p = CHILD_PROCESS_INIT;
 		int ret, sig;
+		static const char *close_notice = NULL;
+
+		if (isatty(2) && !close_notice) {
+			char *term = getenv("TERM");
+
+			if (term && strcmp(term, "dumb"))
+				/*
+				 * go back to the beginning and erase the
+				 * entire line if the terminal is capable
+				 * to do so, to avoid wasting the vertical
+				 * space.
+				 */
+				close_notice = "\r\033[K";
+			else
+				/* otherwise, complete and waste the line */
+				close_notice = "done.\n";
+		}
+
+		if (close_notice) {
+			fprintf(
+				stderr,
+				"Launched your editor ('%s'). Adjust, save, and close the "
+				"file to continue. Waiting for your input... ", editor
+			);
+			fflush(stderr);
+		}

 		p.argv = args;
 		p.env = env;
@@ -53,11 +79,14 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
 		sig = ret - 128;
 		sigchain_pop(SIGINT);
 		sigchain_pop(SIGQUIT);
+
 		if (sig == SIGINT || sig == SIGQUIT)
 			raise(sig);
 		if (ret)
 			return error("There was a problem with the editor '%s'.",
 					editor);
+		if (close_notice)
+			fputs(close_notice, stderr);
 	}

 	if (!buffer)

base-commit: 89ea799ffcc5c8a0547d3c9075eb979256ee95b8
--
2.15.0