* lisp/progmodes/python.el (python-indent-context)

(python-indent-calculate-indentation): Fix auto-identation
behavior for comment blocks.

* test/automated/python-tests.el (python-indent-after-comment-1)
(python-indent-after-comment-2): New tests.

Fixes: debbugs:15916

4 files changed, 104 insertions, 0 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index fc66ed607d4..52d4eff3eb6 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2013-12-12  Fabián Ezequiel Gallina  <fgallina@gnu.org>
+
+        * progmodes/python.el (python-indent-context)
+        (python-indent-calculate-indentation): Fix auto-identation
+        behavior for comment blocks. (Bug#15916)
+
 2013-12-12  Nathan Trapuzzano  <nbtrap@nbtrap.com>  (tiny change)
 
         * progmodes/python.el (python-indent-calculate-indentation): When
diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 669da135644..33039a4d087 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -686,6 +686,8 @@ Context information is returned with a cons with the form:
     \(STATUS . START)
 
 Where status can be any of the following symbols:
+
+ * after-comment: When current line might continue a comment block
  * inside-paren: If point in between (), {} or []
  * inside-string: If point is inside a string
  * after-backslash: Previous line ends in a backslash
@@ -704,6 +706,17 @@ START is the buffer position where the sexp starts."
            (goto-char (line-beginning-position))
            (bobp))
          'no-indent)
+        ;; Comment continuation
+        ((save-excursion
+           (when (and
+                  (or
+                   (python-info-current-line-comment-p)
+                   (python-info-current-line-empty-p))
+                  (progn
+                    (forward-comment -1)
+                    (python-info-current-line-comment-p)))
+             (setq start (point))
+             'after-comment)))
         ;; Inside string
         ((setq start (python-syntax-context 'string ppss))
          'inside-string)
@@ -755,6 +768,9 @@ START is the buffer position where the sexp starts."
       (save-excursion
         (pcase context-status
           (`no-indent 0)
+          (`after-comment
+           (goto-char context-start)
+           (current-indentation))
           ;; When point is after beginning of block just add one level
           ;; of indentation relative to the context-start
           (`after-beginning-of-block
diff --git a/test/ChangeLog b/test/ChangeLog
index ce7208db229..790725b6342 100644
--- a/test/ChangeLog
+++ b/test/ChangeLog
@@ -1,3 +1,8 @@
+2013-12-12  Fabián Ezequiel Gallina  <fgallina@gnu.org>
+
+        * automated/python-tests.el (python-indent-after-comment-1)
+        (python-indent-after-comment-2): New tests.
+
 2013-12-12  Nathan Trapuzzano  <nbtrap@nbtrap.com>
 
         * automated/python-test.el (python-indent-block-enders-1): Rename
diff --git a/test/automated/python-tests.el b/test/automated/python-tests.el
index 58a839a5500..84be598b6dd 100644
--- a/test/automated/python-tests.el
+++ b/test/automated/python-tests.el
@@ -199,6 +199,83 @@ foo = long_function_name(
    (should (eq (car (python-indent-context)) 'inside-paren))
    (should (= (python-indent-calculate-indentation) 4))))
 
+(ert-deftest python-indent-after-comment-1 ()
+  "The most simple after-comment case that shouldn't fail."
+  (python-tests-with-temp-buffer
+   "# Contents will be modified to correct indentation
+class Blag(object):
+    def _on_child_complete(self, child_future):
+        if self.in_terminal_state():
+            pass
+        # We only complete when all our async children have entered a
+    # terminal state. At that point, if any child failed, we fail
+# with the exception with which the first child failed.
+"
+   (python-tests-look-at "# We only complete")
+   (should (eq (car (python-indent-context)) 'after-line))
+   (should (= (python-indent-calculate-indentation) 8))
+   (python-tests-look-at "# terminal state")
+   (should (eq (car (python-indent-context)) 'after-comment))
+   (should (= (python-indent-calculate-indentation) 8))
+   (python-tests-look-at "# with the exception")
+   (should (eq (car (python-indent-context)) 'after-comment))
+   ;; This one indents relative to previous block, even given the fact
+   ;; that it was under-indented.
+   (should (= (python-indent-calculate-indentation) 4))
+   (python-tests-look-at "# terminal state" -1)
+   ;; It doesn't hurt to check again.
+   (should (eq (car (python-indent-context)) 'after-comment))
+   (python-indent-line)
+   (should (= (current-indentation) 8))
+   (python-tests-look-at "# with the exception")
+   (should (eq (car (python-indent-context)) 'after-comment))
+   ;; Now everything should be lined up.
+   (should (= (python-indent-calculate-indentation) 8))))
+
+(ert-deftest python-indent-after-comment-2 ()
+  "Test after-comment in weird cases."
+  (python-tests-with-temp-buffer
+   "# Contents will be modified to correct indentation
+def func(arg):
+    # I don't do much
+    return arg
+    # This comment is badly indented just because.
+    # But we won't mess with the user in this line.
+
+now_we_do_mess_cause_this_is_not_a_comment = 1
+
+# yeah, that.
+"
+   (python-tests-look-at "# I don't do much")
+   (should (eq (car (python-indent-context)) 'after-beginning-of-block))
+   (should (= (python-indent-calculate-indentation) 4))
+   (python-tests-look-at "return arg")
+   ;; Comment here just gets ignored, this line is not a comment so
+   ;; the rules won't apply here.
+   (should (eq (car (python-indent-context)) 'after-beginning-of-block))
+   (should (= (python-indent-calculate-indentation) 4))
+   (python-tests-look-at "# This comment is badly")
+   (should (eq (car (python-indent-context)) 'after-line))
+   ;; The return keyword moves indentation backwards 4 spaces, but
+   ;; let's assume this comment was placed there because the user
+   ;; wanted to (manually adding spaces or whatever).
+   (should (= (python-indent-calculate-indentation) 0))
+   (python-tests-look-at "# but we won't mess")
+   (should (eq (car (python-indent-context)) 'after-comment))
+   (should (= (python-indent-calculate-indentation) 4))
+   ;; Behave the same for blank lines: potentially a comment.
+   (forward-line 1)
+   (should (eq (car (python-indent-context)) 'after-comment))
+   (should (= (python-indent-calculate-indentation) 4))
+   (python-tests-look-at "now_we_do_mess")
+   ;; Here is where comment indentation starts to get ignored and
+   ;; where the user can't freely indent anymore.
+   (should (eq (car (python-indent-context)) 'after-line))
+   (should (= (python-indent-calculate-indentation) 0))
+   (python-tests-look-at "# yeah, that.")
+   (should (eq (car (python-indent-context)) 'after-line))
+   (should (= (python-indent-calculate-indentation) 0))))
+
 (ert-deftest python-indent-inside-paren-1 ()
   "The most simple inside-paren case that shouldn't fail."
   (python-tests-with-temp-buffer