Merge PR #2995

# Conflicts:
#	docs/function-parity.md

crates/functions/src/text.rs

@@ -373,10 +373,10 @@ fn numbervalue(a: &[Arg], c: &mut dyn Ctx) -> R<Value> {
 /// Formats `x` (already rounded) with `decimals` places and optional thousands separators.
 fn format_fixed(x: f64, decimals: i64, commas: bool) -> String {
     let d = decimals.max(0) as usize;
-    let s = format!("{:.*}", d, x.abs());
+    let s = x.abs().to_string();
     let (int_part, frac) = match s.split_once('.') {
-        Some((i, f)) => (i.to_string(), Some(f.to_string())),
-        None => (s.clone(), None),
+        Some((i, f)) => (i, f),
+        None => (s.as_str(), ""),
     };
     let int_part = if commas {
         let b = int_part.as_bytes();
@@ -389,12 +389,14 @@ fn format_fixed(x: f64, decimals: i64, commas: bool) -> String {
         }
         o
     } else {
-        int_part
+        int_part.to_string()
     };
     let mut out = int_part;
-    if let Some(f) = frac {
+    if d > 0 {
+        let frac_len = frac.len().min(d);
         out.push('.');
-        out.push_str(&f);
+        out.push_str(&frac[..frac_len]);
+        out.extend(std::iter::repeat_n('0', d - frac_len));
     }
     out
 }
@@ -1281,6 +1283,18 @@ mod tests {
         is_text(ev("DOLLAR", vec![n(0.5), n(0.0)]), "$1");
         is_text(ev("USDOLLAR", vec![n(1.0)]), "$1.00");
         is_text(ev("USDOLLAR", vec![n(-1234.567), n(1.0)]), "($1,234.6)");
+        let fixed_16 = format!("1.1{}", "0".repeat(15));
+        let dollar_16 = format!("$1.1{}", "0".repeat(15));
+        let fixed_20 = format!("1.005{}", "0".repeat(17));
+        let dollar_20 = format!("$1.005{}", "0".repeat(17));
+        let fixed_127 = format!("1.1{}", "0".repeat(126));
+        let dollar_127 = format!("$1.1{}", "0".repeat(126));
+        is_text(ev("FIXED", vec![n(1.1), n(16.0)]), &fixed_16);
+        is_text(ev("DOLLAR", vec![n(1.1), n(16.0)]), &dollar_16);
+        is_text(ev("FIXED", vec![n(1.005), n(20.0)]), &fixed_20);
+        is_text(ev("DOLLAR", vec![n(1.005), n(20.0)]), &dollar_20);
+        is_text(ev("FIXED", vec![n(1.1), n(127.0)]), &fixed_127);
+        is_text(ev("DOLLAR", vec![n(1.1), n(127.0)]), &dollar_127);
         is_text(ev("T", vec![t("x")]), "x");
         is_text(ev("T", vec![n(1.0)]), "");
     }

docs/function-parity.md

@@ -1,6 +1,6 @@
 # Function parity: worksheet functions and formulas
 
-> **Last reviewed:** 2026-10-31 · **Last updated:** 2026-10-31 · **Change:** minor (UPPER, LOWER and PROPER use single-character Unicode casing to match measured Excel results; locale check: Windows Excel 16.0 build 20527, LCID 1033; earlier: UNICHAR returns `#N/A` for Unicode noncharacters, as observed in Excel; earlier: ECMA.CEILING listed with USDOLLAR as not on Microsoft's list; IMSQRT reproduces the stray real part Excel gives for negative reals, and the other IM* differences from Excel are listed; the LAMBDA row lists the recursion limit and its `#NUM!`, and the error a defined name holding an error gives when called; number text with accounting parentheses coerces like Excel 365; INDEX with one index on a 2-D reference is #REF! as in Excel; SUBTOTAL and AGGREGATE cap the cells they visit, #2175) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
+> **Last reviewed:** 2026-10-31 · **Last updated:** 2026-10-31 · **Change:** minor (FIXED and DOLLAR preserve the rounded number's shortest decimal digits before padding high requested precision; measured in Windows Excel 16.0 build 20527, LCID 1033; earlier: UPPER, LOWER and PROPER use single-character Unicode casing to match measured Excel results; locale check: Windows Excel 16.0 build 20527, LCID 1033; earlier: ECMA.CEILING listed with USDOLLAR as not on Microsoft's list; IMSQRT reproduces the stray real part Excel gives for negative reals, and the other IM* differences from Excel are listed; the LAMBDA row lists the recursion limit and its `#NUM!`, and the error a defined name holding an error gives when called; number text with accounting parentheses coerces like Excel 365; INDEX with one index on a 2-D reference is #REF! as in Excel; SUBTOTAL and AGGREGATE cap the cells they visit, #2175) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
 
 Excel's worksheet functions, category by category, against GridCraft's function library. Part of
 [target-app-parity.md](target-app-parity.md); gaps feed [gaps.md](gaps.md).
@@ -129,6 +129,7 @@ workbooks; results checked in as data, not Excel files) and fixing what it finds
 | 2026-10-31 | minor | BITLSHIFT and BITRSHIFT return `0` for zero operands shifted beyond 53 bits in either direction; nonzero operands retain the `#NUM!` limit, matching Excel |
 | 2026-10-31 | minor | UNICHAR returns `#N/A` for U+FDD0–U+FDEF and U+FFFE/U+FFFF on every plane; adjacent valid characters and existing invalid-range/surrogate errors remain unchanged, matching Excel |
 | 2026-10-31 | minor | UPPER, LOWER and PROPER use single-character casing: `UPPER("Straße")` keeps ß, `LOWER("İ")` returns i, and `PROPER("İSTANBUL")` returns Istanbul, matching Windows Excel 16.0 build 20527 in LCID 1033 |
+| 2026-10-31 | minor | FIXED and DOLLAR format the rounded number's shortest decimal representation before padding requested fractional zeroes, so 1.1 at 16 places and 1.005 at 20 places do not expose binary noise; measured in Windows Excel 16.0 build 20527, LCID 1033 |
 | 2026-10-27 | minor | ECMA.CEILING added to the functions that are in our library but not on Microsoft's list (with USDOLLAR), so the counts don't change |
 | 2026-10-26 | minor | IMSQRT uses Excel's polar route with its cosine reduction, so `IMSQRT("-4")` is `1.22514845490862E-16+2i` as in Excel (exact `2i` before); the rows list the IM* differences still open |
 | 2026-10-25 | minor | LAMBDA row: a LAMBDA that calls itself more than 140 times, and a formula nested past the depth limit, give `#NUM!` (#1809; nesting gave `#CALC!` before). `=Foo(1)` where the defined name Foo holds `#N/A` gives `#N/A`, not `#NAME?` |