0.12.2! Minor lines_strip_indent semantic change.

A minor semantic change to lines_strip_indent: when it encounters
a whitespace-only line, it clips the line to *trailing* in the
LineInfo object.  It used to clip such lines to *leading*.  But this
changed LineInfo.column_number in a nonsensical way.

This behavior is policy going forward: if a lines modifer function
ever clips the entire line, it must clip it to *trailing* rather than
*leading*.  It shouldn't matter one way or another, as whitespace-only
lines arguably shouldn't have any explicit semantics.  But it makes
intuitive sense to me that their empty line should be at column number 1,
rather than 9 or 13 or whatnot.  (Especially considering that with
lines_strip_indent their indent value is synthetic anyway,
inferred by looking ahead.)

Also, a major cleanup to the lines modifier test suites.

README.md

@@ -6134,6 +6134,29 @@ in the **big** test suite.
 
 ## Release history
 
+#### 0.12.2
+
+*2024/09/11*
+
+<dl><dd>
+
+* A minor semantic change to [`lines_strip_indent`](#lines_strip_indentli):
+  when it encounters a whitespace-only line, it clips the line to *trailing*
+  in the `LineInfo` object.  It used to clip such lines to *leading*.  But this
+  changed `LineInfo.column_number` in a nonsensical way.
+
+  This behavior is policy going forward: if a lines modifer function ever clips
+  the entire line, it must clip it to *trailing* rather than *leading*.  It
+  shouldn't matter one way or another, as whitespace-only lines arguably
+  shouldn't have any explicit semantics.  But it makes intuitive sense to me
+  that their empty line should be at column number 1, rather than 9 or 13
+  or whatnot.  (Especially considering that with `lines_strip_indent` their
+  indent value is synthetic anyway, inferred by looking ahead.)
+
+* Major cleanup to the lines modifier test suites.
+
+</dd></dl>
+
 #### 0.12.1
 
 *2024/09/07*

big/__init__.py

@@ -30,4 +30,4 @@
 THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 """
 
-__version__ = "0.12.1"
+__version__ = "0.12.2"

big/text.py

@@ -3404,7 +3404,11 @@ def lines_strip_indent(li):
 
         lstripped = line.lstrip()
         if not lstripped:
-            line = info.clip_leading(line, line)
+            # yes, clip *TRAILING*.
+            # When a line is 100% whitespace,
+            # always clip to trailing.
+            # That way you don't change column_number nonsensically.
+            line = info.clip_trailing(line, line)
             blank_lines.append((info, line))
             # print(f"BL+ {info=} {lstripped=}")
             continue
@@ -3480,6 +3484,10 @@ def lines_filter_empty_lines(li):
         (line_number=3, "a")
         (line_number=5, "b")
 
+    Doesn't strip whitespace (or anything else).  If you want to filter
+    out lines that only contain whitespace, add lines_rstrip to the chain
+    of lines modifiers before lines_filter_empty_lines.
+
     Composable with all the lines_ modifier functions in the big.text module.
     """
     for t in li: