ledger-post-fill: Fix bug

Avoid searching for postings with no amount twice. Instead, change
`ledger-post-xact-total` to return positions where amounts should be
inserted.

ledger-post.el

@@ -193,29 +193,32 @@ the amount and return to ledger."
       (calc))))
 
 (defun ledger-post-xact-total ()
-  "Return (TOTAL . MISSING-COUNT) for the transaction at point.
+  "Return (TOTAL . MISSING-POSITIONS) for the transaction at point.
 
 TOTAL is a commoditized amount representing the total amount of
 the postings in the transaction.
 
-MISSING-COUNT is the number of postings in the transaction that
-do not have an amount specified (such postings do not contribute
-to TOTAL).
+MISSING-POSITIONS is a list of positions in the buffer where the
+transaction do not have an amount specified (such postings do not
+contribute to TOTAL).
 
 Error if the commodities do not match."
   (save-excursion
     (pcase-let ((`(,begin ,end) (ledger-navigate-find-xact-extents (point))))
       (goto-char begin)
       (cl-loop
        while (re-search-forward ledger-post-line-regexp end t)
-       for amount-string = (match-string ledger-regex-post-line-group-amount)
-       count (not amount-string) into missing-count
-       if amount-string
+       for amount-string = (when-let ((amount-string (match-string ledger-regex-post-line-group-amount)))
+                             (unless (string-empty-p (string-trim amount-string))
+                               amount-string))
+       if (not amount-string)
+       collect (or (match-end ledger-regex-post-line-group-account) (point)) into missing-positions
+       else
        collect (ledger-split-commodity-string amount-string) into amounts
        finally return (cons (if amounts
                                 (cl-reduce #'ledger-add-commodity amounts)
                               '(0 nil))
-                            missing-count)))))
+                            missing-positions)))))
 
 (defun ledger-post-fill ()
   "Find a posting with no amount and insert it.
@@ -224,22 +227,19 @@ Even if ledger allows for one missing amount per transaction, you
 might want to insert it anyway."
   (interactive)
   (pcase-let* ((`(,begin ,end) (ledger-navigate-find-xact-extents (point)))
-               (`(,total . ,missing-count) (ledger-post-xact-total))
+               (`(,total . ,missing-positions) (ledger-post-xact-total))
                (missing-amount (ledger-negate-commodity total))
                (amounts-balance (< (abs (car missing-amount)) 0.0001)))
-    (pcase missing-count
+    (pcase (length missing-positions)
       (0 (unless amounts-balance
            (user-error "Postings do not balance, but no posting to fill")))
       (1 (if amounts-balance
              (user-error "Missing amount but amounts balance already")
-           (goto-char begin)
-           (cl-loop
-            while (re-search-forward ledger-post-line-regexp end t)
-            unless (match-beginning ledger-regex-post-line-group-amount)
-            do
-            (goto-char (match-end ledger-regex-post-line-group-account))
-            (insert "  " (ledger-commodity-to-string missing-amount))
-            and return nil)
+           (goto-char (car missing-positions))
+           (insert "  " (ledger-commodity-to-string missing-amount))
+           (just-one-space 0)
+           (unless (equal (point) (line-end-position))
+             (just-one-space 2))
            (ledger-post-align-xact (point))))
       (_ (user-error "More than one posting with missing amount")))))
 

test/post-test.el

@@ -468,7 +468,18 @@ http://bugs.ledger-cli.org/show_bug.cgi?id=946"
 
     (should
      (equal (ledger-post-xact-total)
-            '((10 "$") . 1))))
+            '((10 "$") . (83)))))
+
+  ;; one amount missing with trailing spaces
+  (ledger-tests-with-temp-file
+      "\
+2013-05-01 foo
+    Expenses:Foo                                 $10
+    Assets:Bar       \n"
+
+    (should
+     (equal (ledger-post-xact-total)
+            '((10 "$") . (83)))))
 
   ;; all amounts missing
   (ledger-tests-with-temp-file
@@ -480,7 +491,7 @@ http://bugs.ledger-cli.org/show_bug.cgi?id=946"
 
     (should
      (equal (ledger-post-xact-total)
-            '((0 nil) . 2))))
+            '((0 nil) . (32 47)))))
 
   ;; no amounts missing
   (ledger-tests-with-temp-file
@@ -492,7 +503,7 @@ http://bugs.ledger-cli.org/show_bug.cgi?id=946"
 
     (should
      (equal (ledger-post-xact-total)
-            '((0 "$") . 0)))))
+            '((0 "$") . nil)))))
 
 
 (ert-deftest ledger-post/test-post-xact-total-002 ()
@@ -531,6 +542,21 @@ http://bugs.ledger-cli.org/show_bug.cgi?id=946"
     Assets:Bar                                 $ -10
 ")))
 
+  ;; trailing spaces
+  (ledger-tests-with-temp-file
+      "\
+2013-05-01 foo
+    Expenses:Foo                                 $10
+    Assets:Bar    \n"
+    (ledger-post-fill)
+    (should
+     (equal (buffer-string)
+            "\
+2013-05-01 foo
+    Expenses:Foo                                 $10
+    Assets:Bar                                 $ -10
+")))
+
   ;; no commodity
   (ledger-tests-with-temp-file
       "\