Merge branch 'ds/config-internal-whitespace-fix'

"git config" corrupted literal HT characters written in the
configuration file as part of a value, which has been corrected.

* ds/config-internal-whitespace-fix:
  config.txt: describe handling of whitespace further
  t1300: add more tests for whitespace and inline comments
  config: really keep value-internal whitespace verbatim
  config: minor addition of whitespace

3 files changed, 136 insertions, 21 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 782c2bab90..70b448b132 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -22,9 +22,10 @@ multivalued.
 Syntax
 ~~~~~~
 
-The syntax is fairly flexible and permissive; whitespaces are mostly
-ignored.  The '#' and ';' characters begin comments to the end of line,
-blank lines are ignored.
+The syntax is fairly flexible and permissive.  Whitespace characters,
+which in this context are the space character (SP) and the horizontal
+tabulation (HT), are mostly ignored.  The '#' and ';' characters begin
+comments to the end of line.  Blank lines are ignored.
 
 The file consists of sections and variables.  A section begins with
 the name of the section in square brackets and continues until the next
@@ -63,16 +64,17 @@ the variable is the boolean "true").
 The variable names are case-insensitive, allow only alphanumeric characters
 and `-`, and must start with an alphabetic character.
 
-A line that defines a value can be continued to the next line by
-ending it with a `\`; the backslash and the end-of-line are
-stripped.  Leading whitespaces after 'name =', the remainder of the
-line after the first comment character '#' or ';', and trailing
-whitespaces of the line are discarded unless they are enclosed in
-double quotes.  Internal whitespaces within the value are retained
-verbatim.
-
-Inside double quotes, double quote `"` and backslash `\` characters
-must be escaped: use `\"` for `"` and `\\` for `\`.
+Whitespace characters surrounding `name`, `=` and `value` are discarded.
+Internal whitespace characters within 'value' are retained verbatim.
+Comments starting with either `#` or `;` and extending to the end of line
+are discarded.  A line that defines a value can be continued to the next
+line by ending it with a backslash (`\`);  the backslash and the end-of-line
+characters are discarded.
+
+If `value` needs to contain leading or trailing whitespace characters,
+it must be enclosed in double quotation marks (`"`).  Inside double quotation
+marks, double quote (`"`) and backslash (`\`) characters must be escaped:
+use `\"` for `"` and `\\` for `\`.
 
 The following escape sequences (beside `\"` and `\\`) are recognized:
 `\n` for newline character (NL), `\t` for horizontal tabulation (HT, TAB)
diff --git a/config.c b/config.c
index 3cfeb3d8bd..5072f12e62 100644
--- a/config.c
+++ b/config.c
@@ -817,7 +817,8 @@ static int get_next_char(struct config_source *cs)
 
 static char *parse_value(struct config_source *cs)
 {
-	int quote = 0, comment = 0, space = 0;
+	int quote = 0, comment = 0;
+	size_t trim_len = 0;
 
 	strbuf_reset(&cs->value);
 	for (;;) {
@@ -827,13 +828,17 @@ static char *parse_value(struct config_source *cs)
 				cs->linenr--;
 				return NULL;
 			}
+			if (trim_len)
+				strbuf_setlen(&cs->value, trim_len);
 			return cs->value.buf;
 		}
 		if (comment)
 			continue;
 		if (isspace(c) && !quote) {
+			if (!trim_len)
+				trim_len = cs->value.len;
 			if (cs->value.len)
-				space++;
+				strbuf_addch(&cs->value, c);
 			continue;
 		}
 		if (!quote) {
@@ -842,8 +847,8 @@ static char *parse_value(struct config_source *cs)
 				continue;
 			}
 		}
-		for (; space; space--)
-			strbuf_addch(&cs->value, ' ');
+		if (trim_len)
+			trim_len = 0;
 		if (c == '\\') {
 			c = get_next_char(cs);
 			switch (c) {
@@ -869,7 +874,7 @@ static char *parse_value(struct config_source *cs)
 			continue;
 		}
 		if (c == '"') {
-			quote = 1-quote;
+			quote = 1 - quote;
 			continue;
 		}
 		strbuf_addch(&cs->value, c);
diff --git a/t/t1300-config.sh b/t/t1300-config.sh
index 31c3878687..f4bd69512e 100755
--- a/t/t1300-config.sh
+++ b/t/t1300-config.sh
@@ -11,6 +11,98 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
+test_expect_success 'setup whitespace config' '
+	sed -e "s/^|//" \
+	    -e "s/[$]$//" \
+	    -e "s/X/	/g" >.git/config <<-\EOF
+	[section]
+	|	solid = rock
+	|	sparse = big XX blue
+	|	sparseAndTail = big XX blue $
+	|	sparseAndTailQuoted = "big XX blue "
+	|	sparseAndBiggerTail = big XX blue X X
+	|	sparseAndBiggerTailQuoted = "big XX blue X X"
+	|	sparseAndBiggerTailQuotedPlus = "big XX blue X X"X $
+	|	headAndTail = Xbig blue $
+	|	headAndTailQuoted = "Xbig blue "
+	|	headAndTailQuotedPlus = "Xbig blue " $
+	|	annotated = big blueX# to be discarded
+	|	annotatedQuoted = "big blue"X# to be discarded
+	EOF
+'
+
+test_expect_success 'no internal whitespace' '
+	echo "rock" >expect &&
+	git config --get section.solid >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'internal whitespace' '
+	echo "big QQ blue" | q_to_tab >expect &&
+	git config --get section.sparse >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'internal and trailing whitespace' '
+	echo "big QQ blue" | q_to_tab >expect &&
+	git config --get section.sparseAndTail >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'internal and trailing whitespace, all quoted' '
+	echo "big QQ blue " | q_to_tab >expect &&
+	git config --get section.sparseAndTailQuoted >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'internal and more trailing whitespace' '
+	echo "big QQ blue" | q_to_tab >expect &&
+	git config --get section.sparseAndBiggerTail >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'internal and more trailing whitespace, all quoted' '
+	echo "big QQ blue Q Q" | q_to_tab >expect &&
+	git config --get section.sparseAndBiggerTailQuoted >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'internal and more trailing whitespace, not all quoted' '
+	echo "big QQ blue Q Q" | q_to_tab >expect &&
+	git config --get section.sparseAndBiggerTailQuotedPlus >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'leading and trailing whitespace' '
+	echo "big blue" >expect &&
+	git config --get section.headAndTail >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'leading and trailing whitespace, all quoted' '
+	echo "Qbig blue " | q_to_tab >expect &&
+	git config --get section.headAndTailQuoted >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'leading and trailing whitespace, not all quoted' '
+	echo "Qbig blue " | q_to_tab >expect &&
+	git config --get section.headAndTailQuotedPlus >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'inline comment' '
+	echo "big blue" >expect &&
+	git config --get section.annotated >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'inline comment, quoted' '
+	echo "big blue" >expect &&
+	git config --get section.annotatedQuoted >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'clear default config' '
 	rm -f .git/config
 '
@@ -1066,9 +1158,25 @@ test_expect_success '--null --get-regexp' '
 	test_cmp expect result
 '
 
-test_expect_success 'inner whitespace kept verbatim' '
-	git config section.val "foo 	  bar" &&
-	test_cmp_config "foo 	  bar" section.val
+test_expect_success 'inner whitespace kept verbatim, spaces only' '
+	echo "foo   bar" >expect &&
+	git config section.val "foo   bar" &&
+	git config --get section.val >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'inner whitespace kept verbatim, horizontal tabs only' '
+	echo "fooQQbar" | q_to_tab >expect &&
+	git config section.val "$(cat expect)" &&
+	git config --get section.val >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'inner whitespace kept verbatim, horizontal tabs and spaces' '
+	echo "foo Q  bar" | q_to_tab >expect &&
+	git config section.val "$(cat expect)" &&
+	git config --get section.val >actual &&
+	test_cmp expect actual
 '
 
 test_expect_success SYMLINKS 'symlinked configuration' '