From 53b965c549d6fa0d436bf2c84dea037d23db105e Mon Sep 17 00:00:00 2001
From: "jan.nijtmans" <nijtmans@users.sourceforge.net>
Date: Thu, 15 Feb 2024 20:33:17 +0000
Subject: [PATCH] Fix [578b7e273c03]: Round computed end value to match
 precision of given arguments

---
 generic/tclArithSeries.c | 13 +++++++++----
 tests/lseq.test          | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/generic/tclArithSeries.c b/generic/tclArithSeries.c
index 34fd6355ea8..a29b589d0e5 100755
--- a/generic/tclArithSeries.c
+++ b/generic/tclArithSeries.c
@@ -245,7 +245,7 @@ DupArithSeriesInternalRep(
 	ArithSeriesDbl *srcArithSeriesDblRepPtr =
 	    (ArithSeriesDbl *)srcArithSeriesRepPtr;
 	ArithSeriesDbl *copyArithSeriesDblRepPtr =
-	    (ArithSeriesDbl *) ckalloc(sizeof(ArithSeriesDbl));
+	    (ArithSeriesDbl *)ckalloc(sizeof(ArithSeriesDbl));
 	*copyArithSeriesDblRepPtr = *srcArithSeriesDblRepPtr;
 	copyArithSeriesDblRepPtr->elements = NULL;
 	copyPtr->internalRep.twoPtrValue.ptr1 = copyArithSeriesDblRepPtr;
@@ -327,7 +327,7 @@ NewArithSeriesInt(Tcl_WideInt start, Tcl_WideInt end, Tcl_WideInt step, Tcl_Wide
 	return arithSeriesObj;
     }
 
-    arithSeriesRepPtr = (ArithSeries*) ckalloc(sizeof (ArithSeries));
+    arithSeriesRepPtr = (ArithSeries*)ckalloc(sizeof (ArithSeries));
     arithSeriesRepPtr->isDouble = 0;
     arithSeriesRepPtr->start = start;
     arithSeriesRepPtr->end = end;
@@ -381,7 +381,7 @@ NewArithSeriesDbl(double start, double end, double step, Tcl_WideInt len)
 	return arithSeriesObj;
     }
 
-    arithSeriesRepPtr = (ArithSeriesDbl*) ckalloc(sizeof (ArithSeriesDbl));
+    arithSeriesRepPtr = (ArithSeriesDbl*)ckalloc(sizeof (ArithSeriesDbl));
     arithSeriesRepPtr->isDouble = 1;
     arithSeriesRepPtr->start = start;
     arithSeriesRepPtr->end = end;
@@ -533,7 +533,11 @@ TclNewArithSeriesObj(
 
     if (!endObj) {
 	if (useDoubles) {
+	    // Compute precision based on given command argument values
+	    int precision = maxPrecision(dstart,len,dstep);
 	    dend = dstart + (dstep * (len-1));
+	    // Make computed end value match argument(s) precision
+	    dend = ArithRound(dend, precision);
 	    end = dend;
 	} else {
 	    end = start + (step * (len-1));
@@ -642,6 +646,7 @@ Tcl_Size TclArithSeriesObjLength(Tcl_Obj *arithSeriesObj)
  * 	None.
  *----------------------------------------------------------------------
  */
+
 Tcl_Obj *
 ArithSeriesObjStep(
     Tcl_Obj *arithSeriesObj)
@@ -1094,7 +1099,7 @@ UpdateStringOfArithSeries(Tcl_Obj *arithSeriesObjPtr)
     if (length > 0) arithSeriesObjPtr->bytes[length-1] = '\0';
     arithSeriesObjPtr->length = length-1;
 }
-
+
 /*
  * Local Variables:
  * mode: c
diff --git a/tests/lseq.test b/tests/lseq.test
index 4c1f14bede8..2a7de670069 100644
--- a/tests/lseq.test
+++ b/tests/lseq.test
@@ -692,6 +692,25 @@ test lseq-bug-54329e39c7 {does not cause memory bloat} -constraints {
     expr {($postmem - $premem) < 10}
 } -result 1
 
+test lseq-bug-578b7e273c03-1 {Arithmetic Series Objects get wrong precision when end value is not specified} -body {
+    set bl [expr {2.8 in [lseq 0 count 100 by .1]}]
+    lappend bl [expr {2.8 in [lseq 0 count 200 by .1]}]
+    lappend bl [expr {0.28 in [lseq 0 count 100 by .01]}]
+    lappend bl [expr {0.28 in [lseq 0 count 200 by .01]}]
+    lappend bl [expr {0.286 in [lseq 0 count 100 by .011]}]
+    lappend bl [expr {0.286 in [lseq 0 count 200 by .011]}]
+} -result {1 1 1 1 1 1}
+
+test lseq-bug-578b7e273c03-2 {Arithmetic Series Objects get wrong precision when end value is not specified} -body {
+    set ll [llength [lseq 0 count 100 by .1]]
+    lappend ll [llength [lseq 0 count 200 by .1]]
+    lappend ll [llength [lseq 0 count 100 by .01]]
+    lappend ll [llength [lseq 0 count 200 by .01]]
+    lappend ll [llength [lseq 0 count 100 by .011]]
+    lappend ll [llength [lseq 0 count 200 by .011]]
+} -result {100 200 100 200 100 200}
+
+
 # cleanup
 ::tcltest::cleanupTests