diff: have the diff-* builtins configure diff before initializing revisions

This matches how the diff Porcelain works.  It makes the plumbing commands
respect diff's configuration options, such as indentHeuristic, because
init_revisions() calls diff_setup() which fills in the diff_options struct.

Signed-off-by: Marc Branchaud <marcnarc@xiplink.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/diff-files.c

@@ -20,9 +20,9 @@ int cmd_diff_files(int argc, const char **argv, const char *prefix)
 	int result;
 	unsigned options = 0;
 
+	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	init_revisions(&rev, prefix);
 	gitmodules_config();
-	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	rev.abbrev = 0;
 	precompose_argv(argc, argv);
 

builtin/diff-index.c

@@ -17,9 +17,9 @@ int cmd_diff_index(int argc, const char **argv, const char *prefix)
 	int i;
 	int result;
 
+	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	init_revisions(&rev, prefix);
 	gitmodules_config();
-	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	rev.abbrev = 0;
 	precompose_argv(argc, argv);
 

builtin/diff-tree.c

@@ -105,9 +105,9 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
 	struct setup_revision_opt s_r_opt;
 	int read_stdin = 0;
 
+	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	init_revisions(opt, prefix);
 	gitmodules_config();
-	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	opt->abbrev = 0;
 	opt->diff = 1;
 	opt->disable_stdin = 1;

t/t4061-diff-indent.sh

@@ -213,4 +213,70 @@ test_expect_success 'blame: --no-indent-heuristic overrides config' '
 	compare_blame spaces-expect out-blame2
 '
 
+test_expect_success 'diff-tree: nice spaces with --indent-heuristic' '
+	git diff-tree --indent-heuristic -p old new -- spaces.txt >out-diff-tree-compacted &&
+	compare_diff spaces-compacted-expect out-diff-tree-compacted
+'
+
+test_expect_success 'diff-tree: nice spaces with diff.indentHeuristic' '
+	git -c diff.indentHeuristic=true diff-tree -p old new -- spaces.txt >out-diff-tree-compacted2 &&
+	compare_diff spaces-compacted-expect out-diff-tree-compacted2
+'
+
+test_expect_success 'diff-tree: --no-indent-heuristic overrides config' '
+	git -c diff.indentHeuristic=true diff-tree --no-indent-heuristic -p old new -- spaces.txt >out-diff-tree &&
+	compare_diff spaces-expect out-diff-tree
+'
+
+test_expect_success 'diff-index: nice spaces with --indent-heuristic' '
+	git checkout -B diff-index &&
+	git reset --soft HEAD~ &&
+	git diff-index --indent-heuristic -p old -- spaces.txt >out-diff-index-compacted &&
+	compare_diff spaces-compacted-expect out-diff-index-compacted &&
+	git checkout -f master
+'
+
+test_expect_success 'diff-index: nice spaces with diff.indentHeuristic' '
+	git checkout -B diff-index &&
+	git reset --soft HEAD~ &&
+	git -c diff.indentHeuristic=true diff-index -p old -- spaces.txt >out-diff-index-compacted2 &&
+	compare_diff spaces-compacted-expect out-diff-index-compacted2 &&
+	git checkout -f master
+'
+
+test_expect_success 'diff-index: --no-indent-heuristic overrides config' '
+	git checkout -B diff-index &&
+	git reset --soft HEAD~ &&
+	git -c diff.indentHeuristic=true diff-index --no-indent-heuristic -p old -- spaces.txt >out-diff-index &&
+	compare_diff spaces-expect out-diff-index &&
+	git checkout -f master
+'
+
+test_expect_success 'diff-files: nice spaces with diff.indentHeuristic' '
+	git checkout -B diff-files &&
+	git reset HEAD~ &&
+	git -c diff.indentHeuristic=true diff-files -p spaces.txt >out-diff-files-raw &&
+	grep -v index out-diff-files-raw >out-diff-files-compacted &&
+	compare_diff spaces-compacted-expect out-diff-files-compacted &&
+	git checkout -f master
+'
+
+test_expect_success 'diff-files: nice spaces with diff.indentHeuristic' '
+	git checkout -B diff-files &&
+	git reset HEAD~ &&
+	git -c diff.indentHeuristic=true diff-files -p spaces.txt >out-diff-files-raw2 &&
+	grep -v index out-diff-files-raw2 >out-diff-files-compacted2 &&
+	compare_diff spaces-compacted-expect out-diff-files-compacted2 &&
+	git checkout -f master
+'
+
+test_expect_success 'diff-files: --no-indent-heuristic overrides config' '
+	git checkout -B diff-files &&
+	git reset HEAD~ &&
+	git -c diff.indentHeuristic=true diff-files --no-indent-heuristic -p spaces.txt >out-diff-files-raw3 &&
+	grep -v index out-diff-files-raw3 >out-diff-files &&
+	compare_diff spaces-expect out-diff-files &&
+	git checkout -f master
+'
+
 test_done