Re: Diffing submodule does not yield complete logs for merge commits

[Robert Dailey <rcdailey.lists@gmail.com>]

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On Tue, May 5, 2015 at 12:49 AM, Johannes Schindelin
<johannes.schindelin@gmx.de> wrote:
> Hi Robert,
>
> On 2015-05-04 22:21, Robert Dailey wrote:
>
>> Since I am not a linux user, I have implemented this feature against
>> the Git for Windows fork of git. I am not able to verify changes if I
>> make them directly against the Git repository.
>
> That is why I worked so hard on support of Vagrant: https://github.com/msysgit/msysgit/wiki/Vagrant -- in short, it makes it dead easy for you to set up a *minimal* Linux VM inside your Git SDK and interact with it via ssh.
>
> With the Vagrant solution, you can easily test Linux Git even on Windows.
>
> Ciao,
> Johannes

At the moment I have a "half-ass" patch attached. This implements the
feature itself. I'm able to test this and it seems to be working.
Please note I'm a C++ developer and straight C / Bash are not my
strong suits. I apologize in advance for any mistakes. I am open to
taking recommendations for corrections.

I'm not sure how I can verify the feature in a unit test. In addition
to learning bash scripting well enough to write the test, I am not
sure how to use git to check for the additional commits. Plus the repo
for the test will need to handle a submodule change to a merge commit
as well. Any advice on setting up a good test case for this? What
conditions should I check for, as far as log output goes?

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From 66db185ab76d0d893792d03dc0fc4913d868f218 Mon Sep 17 00:00:00 2001
From: Robert Dailey <rcdailey@gmail.com>
Date: Tue, 5 May 2015 21:56:26 +0100
Subject: [PATCH] Add 'full-log' option to diff.submodule

Like the 'log' option to `diff --submodule`, 'full-log' provides
logs without the `--first-parent` option.
---
 diff.c      | 16 ++++++++++++----
 diff.h      |  1 +
 submodule.c |  9 +++++----
 submodule.h |  3 ++-
 4 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/diff.c b/diff.c
index 7500c55..58c4872 100644
--- a/diff.c
+++ b/diff.c
@@ -128,10 +128,18 @@ static int parse_dirstat_params(struct diff_options *options, const char *params
 
 static int parse_submodule_params(struct diff_options *options, const char *value)
 {
-	if (!strcmp(value, "log"))
+	if (!strcmp(value, "log")) {
 		DIFF_OPT_SET(options, SUBMODULE_LOG);
-	else if (!strcmp(value, "short"))
+		DIFF_OPT_CLR(options, SUBMODULE_FULL_LOG);
+	}
+	else if (!strcmp(value, "full-log")) {
+		DIFF_OPT_SET(options, SUBMODULE_FULL_LOG);
+		DIFF_OPT_CLR(options, SUBMODULE_LOG);
+	}
+	else if (!strcmp(value, "short")) {
 		DIFF_OPT_CLR(options, SUBMODULE_LOG);
+		DIFF_OPT_CLR(options, SUBMODULE_FULL_LOG);
+	}
 	else
 		return -1;
 	return 0;
@@ -2240,7 +2248,7 @@ static void builtin_diff(const char *name_a,
 	struct strbuf header = STRBUF_INIT;
 	const char *line_prefix = diff_line_prefix(o);
 
-	if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
+	if ((DIFF_OPT_TST(o, SUBMODULE_LOG) || DIFF_OPT_TST(o, SUBMODULE_FULL_LOG)) &&
 			(!one->mode || S_ISGITLINK(one->mode)) &&
 			(!two->mode || S_ISGITLINK(two->mode))) {
 		const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
@@ -2248,7 +2256,7 @@ static void builtin_diff(const char *name_a,
 		show_submodule_summary(o->file, one->path ? one->path : two->path,
 				line_prefix,
 				one->sha1, two->sha1, two->dirty_submodule,
-				meta, del, add, reset);
+				meta, del, add, reset, DIFF_OPT_TST(o, SUBMODULE_FULL_LOG));
 		return;
 	}
 
diff --git a/diff.h b/diff.h
index b4a624d..95f319c 100644
--- a/diff.h
+++ b/diff.h
@@ -90,6 +90,7 @@ typedef struct strbuf *(*diff_prefix_fn_t)(struct diff_options *opt, void *data)
 #define DIFF_OPT_DIRSTAT_BY_LINE     (1 << 28)
 #define DIFF_OPT_FUNCCONTEXT         (1 << 29)
 #define DIFF_OPT_PICKAXE_IGNORE_CASE (1 << 30)
+#define DIFF_OPT_SUBMODULE_FULL_LOG  (1 << 31)
 
 #define DIFF_OPT_TST(opts, flag)    ((opts)->flags & DIFF_OPT_##flag)
 #define DIFF_OPT_TOUCHED(opts, flag)    ((opts)->touched_flags & DIFF_OPT_##flag)
diff --git a/submodule.c b/submodule.c
index d37d400..f98173e 100644
--- a/submodule.c
+++ b/submodule.c
@@ -290,14 +290,14 @@ void handle_ignore_submodules_arg(struct diff_options *diffopt,
 
 static int prepare_submodule_summary(struct rev_info *rev, const char *path,
 		struct commit *left, struct commit *right,
-		int *fast_forward, int *fast_backward)
+		int *fast_forward, int *fast_backward, unsigned full_log)
 {
 	struct commit_list *merge_bases, *list;
 
 	init_revisions(rev, NULL);
 	setup_revisions(0, NULL, rev, NULL);
 	rev->left_right = 1;
-	rev->first_parent_only = 1;
+	rev->first_parent_only = full_log ? 0 : 1;
 	left->object.flags |= SYMMETRIC_LEFT;
 	add_pending_object(rev, &left->object, path);
 	add_pending_object(rev, &right->object, path);
@@ -363,7 +363,8 @@ void show_submodule_summary(FILE *f, const char *path,
 		const char *line_prefix,
 		unsigned char one[20], unsigned char two[20],
 		unsigned dirty_submodule, const char *meta,
-		const char *del, const char *add, const char *reset)
+		const char *del, const char *add, const char *reset,
+		unsigned full_log)
 {
 	struct rev_info rev;
 	struct commit *left = NULL, *right = NULL;
@@ -381,7 +382,7 @@ void show_submodule_summary(FILE *f, const char *path,
 		 !(right = lookup_commit_reference(two)))
 		message = "(commits not present)";
 	else if (prepare_submodule_summary(&rev, path, left, right,
-					   &fast_forward, &fast_backward))
+					   &fast_forward, &fast_backward, full_log))
 		message = "(revision walker failed)";
 
 	if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
diff --git a/submodule.h b/submodule.h
index 7beec48..301358b 100644
--- a/submodule.h
+++ b/submodule.h
@@ -26,7 +26,8 @@ void show_submodule_summary(FILE *f, const char *path,
 		const char *line_prefix,
 		unsigned char one[20], unsigned char two[20],
 		unsigned dirty_submodule, const char *meta,
-		const char *del, const char *add, const char *reset);
+		const char *del, const char *add, const char *reset,
+		unsigned full_log);
 void set_config_fetch_recurse_submodules(int value);
 void check_for_new_submodule_commits(unsigned char new_sha1[20]);
 int fetch_populated_submodules(const struct argv_array *options,
-- 
2.4.1.windows.1