[css-flexbox] Slightly restructured the text for resolving flexible lengths to resolve #5179. No normative changes intended.

Author: tabatkins

css-flexbox-1/Overview.bs

@@ -2836,10 +2836,18 @@ Resolving Flexible Lengths</h3>
 			use the flex grow factor for the rest of this algorithm;
 			otherwise, use the flex shrink factor.
 
+		<li>
+			Each item in the flex line has a <dfn>target main size</dfn>,
+			initially set to its [=flex base size=].
+			Each item is initially <i>unfrozen</i>
+			and may become <i>frozen</i>.
+
+			Note: An item’s [=target main size=] doesn’t change after freezing.
+
 		<li>
 			<strong>Size inflexible items.</strong>
 			Freeze,
-			setting its <dfn>target main size</dfn>
+			setting its [=target main size=]
 			to its <a>hypothetical main size</a>&hellip;
 			<ul>
 				<li>
@@ -2856,10 +2864,8 @@ Resolving Flexible Lengths</h3>
 
 		<li>
 			<strong>Calculate <dfn>initial free space</dfn>.</strong>
-			Sum the outer sizes of all items on the line,
+			Sum the outer [=target main sizes=] of all items on the line,
 			and subtract this from the flex container's inner <a>main size</a>.
-			For frozen items, use their outer <a>target main size</a>;
-			for other items, use their outer <a>flex base size</a>.
 
 		<li>
 			Loop:
@@ -2880,16 +2886,14 @@ Resolving Flexible Lengths</h3>
 					use this as the <a>remaining free space</a>.
 
 				<li>
-					<strong>Distribute free space proportional to the flex factors.</strong>
+					If the [=remaining free space=] is non-zero,
+					<strong>distribute it proportional to the flex factors</strong>:
 
 					<dl>
-						<dt>If the <a>remaining free space</a> is zero
-						<dd>
-							Do nothing.
-
 						<dt>If using the <a>flex grow factor</a>
 						<dd>
-							Find the ratio of the item's flex grow factor
+							For every unfrozen item on the line,
+							find the ratio of the item's flex grow factor
 							to the sum of the flex grow factors of all unfrozen items on the line.
 							Set the item's <a>target main size</a> to its <a>flex base size</a>
 							plus a fraction of the <a>remaining free space</a> proportional to the ratio.
@@ -2905,10 +2909,6 @@ Resolving Flexible Lengths</h3>
 							minus a fraction of the absolute value of the <a>remaining free space</a> proportional to the ratio.
 							<span class='note'>Note this may result in a negative inner <a>main size</a>;
 							it will be corrected in the next step.</span>
-
-						<dt>Otherwise
-						<dd>
-							Do nothing.
 					</dl>
 
 				<li>
@@ -2941,6 +2941,9 @@ Resolving Flexible Lengths</h3>
 							Freeze all the items with max violations.
 					</dl>
 
+					Note: This freezes at least one item,
+					ensuring that the loop makes progress and eventually terminates.
+
 				<li>
 					Return to the start of this loop.
 			</ol>
@@ -3704,7 +3707,7 @@ Changes since the <a href="https://www.w3.org/TR/2018/CR-css-flexbox-1-20181119/
 	<ul>
 		<li id="change-2019-bracket-range-notation">
 			Changed syntax to use <a>bracketed range notation</a> to reflect the prose restrictions on negative values.
-      
+
 		<li id="change-2018-used-cross-size">
 			Clarified that the [=flex base size=] calculations
 			rely on the <em>used</em> [=cross size=].
@@ -3714,6 +3717,10 @@ Changes since the <a href="https://www.w3.org/TR/2018/CR-css-flexbox-1-20181119/
 				its <ins>used</ins> inner cross size
 				and the flex item’s intrinsic aspect ratio.
 			</blockquote>
+
+		<li id="change-2018-flexible-length-text">
+			Slightly restructured the prose in [[#resolve-flexible-lengths]]
+			to resolve <a href="https://github.com/w3c/csswg-drafts/issues/5179">Issue 5179</a>.
 	</ul>
 
 <h3 id="changes-20171016">