5 files changed, 40 insertions, 8 deletions
diff --git a/changelog.md b/changelog.md
index e7ab1a298..4aa22b9d7 100644
--- a/changelog.md
+++ b/changelog.md
@@ -31,7 +31,11 @@
 - The file descriptors created for internal bookkeeping by `ioselector_kqueue`
   and `ioselector_epoll` will no longer be leaked to child processes.
 
+- `strutils.formatFloat` with `precision = 0` has been restored to the version
+  1 behaviour that produces a trailing dot, e.g. `formatFloat(3.14159, precision = 0)`
+  is now `3.`, not `3`.
 - `critbits` adds `commonPrefixLen`.
+
 - `relativePath(rel, abs)` and `relativePath(abs, rel)` used to silently give wrong results
   (see #13222); instead they now use `getCurrentDir` to resolve those cases,
   and this can now throw in edge cases where `getCurrentDir` throws.
diff --git a/lib/pure/strformat.nim b/lib/pure/strformat.nim
index 838baaf02..5f7ef380d 100644
--- a/lib/pure/strformat.nim
+++ b/lib/pure/strformat.nim
@@ -692,11 +692,11 @@ when isMainModule:
   check &"{-123.456:.3f}", "-123.456"
   check &"{123.456:1g}", "123.456"
   check &"{123.456:.1f}", "123.5"
-  check &"{123.456:.0f}", "123"
+  check &"{123.456:.0f}", "123."
   check &"{123.456:>9.3f}", "  123.456"
   check &"{123.456:9.3f}", "  123.456"
   check &"{123.456:>9.4f}", " 123.4560"
-  check &"{123.456:>9.0f}", "      123"
+  check &"{123.456:>9.0f}", "     123."
   check &"{123.456:<9.4f}", "123.4560 "
 
   # Float (scientific) tests
diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim
index ff76fa94f..a1f80ad76 100644
--- a/lib/pure/strutils.nim
+++ b/lib/pure/strutils.nim
@@ -2430,10 +2430,6 @@ proc formatBiggestFloat*(f: BiggestFloat, format: FloatFormatMode = ffDefault,
       # but nothing else is possible:
       if buf[i] in {'.', ','}: result[i] = decimalSep
       else: result[i] = buf[i]
-    since (1, 1):
-      # remove trailing dot, compatible with Python's formatter and JS backend
-      if result[^1] == decimalSep:
-        result.setLen(len(result)-1)
     when defined(windows):
       # VS pre 2015 violates the C standard: "The exponent always contains at
       # least two digits, and only as many more digits as necessary to
@@ -2936,7 +2932,8 @@ proc isNilOrWhitespace*(s: string): bool {.noSideEffect, procvar, rtl,
 when isMainModule:
   proc nonStaticTests =
     doAssert formatBiggestFloat(1234.567, ffDecimal, -1) == "1234.567000"
-    doAssert formatBiggestFloat(1234.567, ffDecimal, 0) == "1235" # bugs 8242, 12586
+    when not defined(js):
+      doAssert formatBiggestFloat(1234.567, ffDecimal, 0) == "1235." # bugs 8242, 12586
     doAssert formatBiggestFloat(1234.567, ffDecimal, 1) == "1234.6"
     doAssert formatBiggestFloat(0.00000000001, ffDecimal, 11) == "0.00000000001"
     doAssert formatBiggestFloat(0.00000000001, ffScientific, 1, ',') in
diff --git a/tests/destructor/tnewruntime_strutils.nim b/tests/destructor/tnewruntime_strutils.nim
index 9afb507f7..b0bceb4b5 100644
--- a/tests/destructor/tnewruntime_strutils.nim
+++ b/tests/destructor/tnewruntime_strutils.nim
@@ -37,7 +37,7 @@ bug12899()
 
 proc nonStaticTests =
   doAssert formatBiggestFloat(1234.567, ffDecimal, -1) == "1234.567000"
-  doAssert formatBiggestFloat(1234.567, ffDecimal, 0) == "1235" # bugs 8242, 12586
+  doAssert formatBiggestFloat(1234.567, ffDecimal, 0) == "1235." # bugs 8242, 12586
   doAssert formatBiggestFloat(1234.567, ffDecimal, 1) == "1234.6"
   doAssert formatBiggestFloat(0.00000000001, ffDecimal, 11) == "0.00000000001"
   doAssert formatBiggestFloat(0.00000000001, ffScientific, 1, ',') in
diff --git a/tests/stdlib/tstrformat.nim b/tests/stdlib/tstrformat.nim
index 403372aed..7db001979 100644
--- a/tests/stdlib/tstrformat.nim
+++ b/tests/stdlib/tstrformat.nim
@@ -173,3 +173,34 @@ block:
               y = 234
               z = true
            """
+
+
+# tests from the very own strformat documentation!
+
+let msg = "hello"
+doAssert fmt"{msg}\n" == "hello\\n"
+
+doAssert &"{msg}\n" == "hello\n"
+
+doAssert fmt"{msg}{'\n'}" == "hello\n"
+doAssert fmt("{msg}\n") == "hello\n"
+doAssert "{msg}\n".fmt == "hello\n"
+
+doAssert &"""{"abc":>4}""" == " abc"
+doAssert &"""{"abc":<4}""" == "abc "
+
+doAssert fmt"{-12345:08}" == "-0012345"
+doAssert fmt"{-1:3}" == " -1"
+doAssert fmt"{-1:03}" == "-01"
+doAssert fmt"{16:#X}" == "0x10"
+
+doAssert fmt"{123.456}" == "123.456"
+doAssert fmt"{123.456:>9.3f}" == "  123.456"
+doAssert fmt"{123.456:9.3f}" == "  123.456"
+doAssert fmt"{123.456:9.4f}" == " 123.4560"
+doAssert fmt"{123.456:>9.0f}" == "     123."
+doAssert fmt"{123.456:<9.4f}" == "123.4560 "
+
+doAssert fmt"{123.456:e}" == "1.234560e+02"
+doAssert fmt"{123.456:>13e}" == " 1.234560e+02"
+doAssert fmt"{123.456:13e}" == " 1.234560e+02"