[GSoC PATCH v2] userdiff: add builtin driver for gitconfig syntax

[Lucas Seiki Oshiro <lucasseikioshiro@gmail.com>]

From Documentation/config.adoc:

Add a new builtin driver for gitconfig files, where:

- the funcname regular expression matches sections and subsections,
  i. e. the pattern [SECTION] or [SECTION "SUBSECTION"], where the
  section is composed by alphanumeric numbers, `-` and `.`, and
  subsection names may be composed by any characters;

- word_regex is more permissive than the syntax specification, matching
  any word with one or more non-whitespace characters without checking
  if it is a valid variable name or value.

A more detailed description on the format of gitconfig syntax can be
seen by running `git show cfd409:Documentation/config.txt`.

Also add tests for the new userdiff driver. These files define sections
and subsections, with and without indentation.

Helped-by: Patrick Steinhardt <ps@pks.im>
Helped-by: D. Ben Knoble <ben.knoble@gmail.com>
Signed-off-by: Lucas Seiki Oshiro <lucasseikioshiro@gmail.com>
---

Hi!

This v2 removes the quoted text from the commit message, using a reference to
the documentation file and the commit that last changed the lines where it was
copied before.

I'm also adding the missing newlines at the end of the test files.

 t/t4018/gitconfig-section             | 6 ++++++
 t/t4018/gitconfig-section-noindent    | 6 ++++++
 t/t4018/gitconfig-subsection          | 8 ++++++++
 t/t4018/gitconfig-subsection-noindent | 8 ++++++++
 userdiff.c                            | 4 ++++
 5 files changed, 32 insertions(+)
 create mode 100644 t/t4018/gitconfig-section
 create mode 100644 t/t4018/gitconfig-section-noindent
 create mode 100644 t/t4018/gitconfig-subsection
 create mode 100644 t/t4018/gitconfig-subsection-noindent

diff --git a/t/t4018/gitconfig-section b/t/t4018/gitconfig-section
new file mode 100644
index 0000000000..18c85eb613
--- /dev/null
+++ b/t/t4018/gitconfig-section
@@ -0,0 +1,6 @@
+[RIGHT]
+        # comment
+        ; comment
+        name = value
+        ChangeMe
+
diff --git a/t/t4018/gitconfig-section-noindent b/t/t4018/gitconfig-section-noindent
new file mode 100644
index 0000000000..5c58a7ac92
--- /dev/null
+++ b/t/t4018/gitconfig-section-noindent
@@ -0,0 +1,6 @@
+[RIGHT]
+# comment
+; comment
+name = value
+ChangeMe
+
diff --git a/t/t4018/gitconfig-subsection b/t/t4018/gitconfig-subsection
new file mode 100644
index 0000000000..569be04a32
--- /dev/null
+++ b/t/t4018/gitconfig-subsection
@@ -0,0 +1,8 @@
+[LEFT]
+
+[LEFT "RIGHT"]
+      # comment
+      ; comment
+      name = value
+      ChangeMe
+
diff --git a/t/t4018/gitconfig-subsection-noindent b/t/t4018/gitconfig-subsection-noindent
new file mode 100644
index 0000000000..85c5074f47
--- /dev/null
+++ b/t/t4018/gitconfig-subsection-noindent
@@ -0,0 +1,8 @@
+[LEFT]
+
+[LEFT "RIGHT"]
+# comment
+; comment
+name = value
+ChangeMe
+
diff --git a/userdiff.c b/userdiff.c
index 340c4eb4f7..5bbcc2b690 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -198,6 +198,10 @@ IPATTERN("fountain",
 	 "^((\\.[^.]|(int|ext|est|int\\.?/ext|i/e)[. ]).*)$",
 	 /* -- */
 	 "[^ \t-]+"),
+PATTERNS("gitconfig",
+         "^\\[[a-zA-Z0-9]+\\]|\\[[a-zA-Z0-9]+[ \t]+\".+\"\\]$",
+         /* -- */
+         "[^ \t]+"),
 PATTERNS("golang",
 	 /* Functions */
 	 "^[ \t]*(func[ \t]*.*(\\{[ \t]*)?)\n"
-- 
2.39.5 (Apple Git-154)