From 3f29ecb9fe84dd23b965d97713ab0a35c3bca2e4 Mon Sep 17 00:00:00 2001
From: Shurong Cao <CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 07:59:29 +0800
Subject: [PATCH 01/14] fix(sankey): derive effective node.pad clamp from
 layout geometry

The node.pad warning read the clamped padding back through
sankey.nodePadding(). In @plotly/d3-sankey@0.7.x that getter returns
the post-layout clamped value, but since 0.12.x (upstream split of dy/py)
it returns the configured value, so the comparison is never true and the
warning never fires after a dependency upgrade.

Measure the smallest vertical gap between consecutive nodes in any one
column instead; this works regardless of the installed d3-sankey
version. Regression tests cover both the clamped and non-clamped paths.

Refs #7832
---
 src/traces/sankey/render.js       | 26 ++++++++++++--
 test/jasmine/tests/sankey_test.js | 59 +++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/src/traces/sankey/render.js b/src/traces/sankey/render.js
index 83f8bbb2f98..b797d1e783b 100644
--- a/src/traces/sankey/render.js
+++ b/src/traces/sankey/render.js
@@ -90,8 +90,30 @@ function sankeyModel(layout, d, traceIndex) {
 
     var graph = sankey();
 
-    if(sankey.nodePadding() < nodePad) {
-        Lib.warn('node.pad was reduced to ', sankey.nodePadding(), ' to fit within the figure.');
+    // Derive the effective (post-clamp) node padding from the laid-out node
+    // geometry instead of reading it back through `sankey.nodePadding()`.
+    // In @plotly/d3-sankey@0.7.x that getter returned the clamped value after
+    // the layout ran, but since 0.12.x it returns the user-configured value
+    // (upstream split `dy` from `py`), so a getter-based check would never
+    // fire. Measuring the smallest vertical gap between consecutive nodes in
+    // any one column is version-independent. See #7832.
+    var effectivePad = nodePad;
+    var columns = {};
+    graph.nodes.forEach(function(node) {
+        var col = Math.round(node.x0);
+        if(!columns[col]) columns[col] = [];
+        columns[col].push([node.y0, node.y1]);
+    });
+    for(var key in columns) {
+        var column = columns[key].sort(function(a, b) { return a[0] - b[0]; });
+        for(i = 1; i < column.length; i++) {
+            var gap = column[i][0] - column[i - 1][1];
+            if(gap < effectivePad) effectivePad = gap;
+        }
+    }
+
+    if(effectivePad < nodePad) {
+        Lib.warn('node.pad was reduced to ', effectivePad, ' to fit within the figure.');
     }
 
     // Counters for nested loops
diff --git a/test/jasmine/tests/sankey_test.js b/test/jasmine/tests/sankey_test.js
index d82ecdf9296..146c22536e7 100644
--- a/test/jasmine/tests/sankey_test.js
+++ b/test/jasmine/tests/sankey_test.js
@@ -95,8 +95,67 @@ describe('sankey tests', function () {
         });
     });
 
+
     describe('sankey global defaults', function () {
         it('should not coerce trace opacity', function () {
+
+
+    describe('node.pad reduction warning', function() {
+        // The warning must be driven by the effective (post-clamp) padding,
+        // not by reading `sankey.nodePadding()` back, which since
+        // @plotly/d3-sankey@0.12.x returns the configured value instead of
+        // the clamped one - see #7832.
+        var padMock = [{
+            type: 'sankey',
+            layoutversion: 2,
+            domain: {x: [0, 1], y: [0, 1]},
+            node: {
+                label: Array.from({length: 24}, function(_, i) { return 'n' + i; }),
+                pad: 30,
+                thickness: 10
+            },
+            link: {
+                source: Array.from({length: 23}, function(_, i) { return i; }),
+                target: Array.from({length: 23}, function(_, i) { return i + 1; }),
+                value: Array.from({length: 23}, function() { return 1; })
+            }
+        }];
+
+        it('warns when the figure is too small for node.pad', function(done) {
+            var warnings = [];
+            spyOn(Lib, 'warn').and.callFake(function(msg) {
+                warnings.push(msg);
+            });
+
+            var gd = createGraphDiv('pad-warn-small', 300, 100);
+            Plotly.newPlot(gd, Lib.extendDeep([], padMock))
+                .then(function() {
+                    expect(warnings.length).toEqual(1);
+                    expect(warnings[0][0]).toBe('node.pad was reduced to ');
+                    expect(warnings[0][1]).toBeLessThan(30);
+                    return Plotly.purge(gd);
+                })
+                .then(function() { destroyGraphDiv(gd); })
+                .then(done, done.fail);
+        });
+
+        it('does not warn when the figure fits node.pad', function(done) {
+            var warnings = [];
+            spyOn(Lib, 'warn').and.callFake(function(msg) {
+                warnings.push(msg);
+            });
+
+            var gd = createGraphDiv('pad-warn-large', 700, 900);
+            Plotly.newPlot(gd, Lib.extendDeep([], padMock))
+                .then(function() {
+                    expect(warnings.length).toEqual(0);
+                    return Plotly.purge(gd);
+                })
+                .then(function() { destroyGraphDiv(gd); })
+                .then(done, done.fail);
+        });
+    });
+ (fix(sankey): derive effective node.pad clamp from layout geometry)
             var gd = Lib.extendDeep({}, mock);
 
             supplyAllDefaults(gd);

From a95a89cfe8e8663d6843cf226c312b381790f552 Mon Sep 17 00:00:00 2001
From: Shurong Cao <CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 08:11:22 +0800
Subject: [PATCH 02/14] fix(sankey): declare loop counter locally; add draftlog

The inner loop reused the file-scope `i` before its var declaration
line, tripping biome's noInvalidUseBeforeDeclaration, and the PR was
missing its changelog draftlog entry.
---
 draftlogs/7977_fix.md       | 1 +
 src/traces/sankey/render.js | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)
 create mode 100644 draftlogs/7977_fix.md

diff --git a/draftlogs/7977_fix.md b/draftlogs/7977_fix.md
new file mode 100644
index 00000000000..56a42eef789
--- /dev/null
+++ b/draftlogs/7977_fix.md
@@ -0,0 +1 @@
+ - Fix `node.pad` reduction warning so it derives the effective (post-clamp) padding from the laid-out node geometry instead of reading `sankey.nodePadding()`, which since @plotly/d3-sankey 0.12.x returns the configured value and made the warning never fire [[#7977](https://github.com/plotly/plotly.js/pull/7977)]
diff --git a/src/traces/sankey/render.js b/src/traces/sankey/render.js
index b797d1e783b..87116e31d99 100644
--- a/src/traces/sankey/render.js
+++ b/src/traces/sankey/render.js
@@ -106,8 +106,8 @@ function sankeyModel(layout, d, traceIndex) {
     });
     for(var key in columns) {
         var column = columns[key].sort(function(a, b) { return a[0] - b[0]; });
-        for(i = 1; i < column.length; i++) {
-            var gap = column[i][0] - column[i - 1][1];
+        for(var n = 1; n < column.length; n++) {
+            var gap = column[n][0] - column[n - 1][1];
             if(gap < effectivePad) effectivePad = gap;
         }
     }

From 3ab85f85d8563d0aa3cab55f8bef7f167cd2f52a Mon Sep 17 00:00:00 2001
From: Shurong Cao <CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 08:21:21 +0800
Subject: [PATCH 03/14] test(sankey): drive pad-warning tests by explicit
 layout size

The karma viewport size does not determine the plot size, so the
small-figure case rendered at default dimensions and never clamped.
Set explicit layout width/height (and small margins) instead, and use
the standard createGraphDiv() helper.
---
 test/jasmine/tests/sankey_test.js | 48 +++++++++++++++++++------------
 1 file changed, 30 insertions(+), 18 deletions(-)

diff --git a/test/jasmine/tests/sankey_test.js b/test/jasmine/tests/sankey_test.js
index 146c22536e7..3d9d3ef6877 100644
--- a/test/jasmine/tests/sankey_test.js
+++ b/test/jasmine/tests/sankey_test.js
@@ -105,21 +105,27 @@ describe('sankey tests', function () {
         // not by reading `sankey.nodePadding()` back, which since
         // @plotly/d3-sankey@0.12.x returns the configured value instead of
         // the clamped one - see #7832.
-        var padMock = [{
-            type: 'sankey',
-            layoutversion: 2,
-            domain: {x: [0, 1], y: [0, 1]},
-            node: {
-                label: Array.from({length: 24}, function(_, i) { return 'n' + i; }),
-                pad: 30,
-                thickness: 10
-            },
-            link: {
-                source: Array.from({length: 23}, function(_, i) { return i; }),
-                target: Array.from({length: 23}, function(_, i) { return i + 1; }),
-                value: Array.from({length: 23}, function() { return 1; })
+        var padMock = {
+            data: [{
+                type: 'sankey',
+                layoutversion: 2,
+                node: {
+                    label: Array.from({length: 24}, function(_, i) { return 'n' + i; }),
+                    pad: 30,
+                    thickness: 10
+                },
+                link: {
+                    source: Array.from({length: 23}, function(_, i) { return i; }),
+                    target: Array.from({length: 23}, function(_, i) { return i + 1; }),
+                    value: Array.from({length: 23}, function() { return 1; })
+                }
+            }],
+            layout: {
+                width: 500,
+                height: 500,
+                margin: {l: 10, r: 10, t: 10, b: 10}
             }
-        }];
+        };
 
         it('warns when the figure is too small for node.pad', function(done) {
             var warnings = [];
@@ -127,8 +133,11 @@ describe('sankey tests', function () {
                 warnings.push(msg);
             });
 
-            var gd = createGraphDiv('pad-warn-small', 300, 100);
-            Plotly.newPlot(gd, Lib.extendDeep([], padMock))
+            var fig = Lib.extendDeep({}, padMock);
+            fig.layout.width = 200;
+            fig.layout.height = 100;
+            var gd = createGraphDiv();
+            Plotly.newPlot(gd, fig)
                 .then(function() {
                     expect(warnings.length).toEqual(1);
                     expect(warnings[0][0]).toBe('node.pad was reduced to ');
@@ -145,8 +154,11 @@ describe('sankey tests', function () {
                 warnings.push(msg);
             });
 
-            var gd = createGraphDiv('pad-warn-large', 700, 900);
-            Plotly.newPlot(gd, Lib.extendDeep([], padMock))
+            var fig = Lib.extendDeep({}, padMock);
+            fig.layout.width = 700;
+            fig.layout.height = 900;
+            var gd = createGraphDiv();
+            Plotly.newPlot(gd, fig)
                 .then(function() {
                     expect(warnings.length).toEqual(0);
                     return Plotly.purge(gd);

From 1752e5d8b5c204b964399f86f8cf89f10f022344 Mon Sep 17 00:00:00 2001
From: Shurong Cao <CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 08:30:41 +0800
Subject: [PATCH 04/14] test(sankey): use star topology so clamping is actually
 exercised

A 24-node chain places one node per column, so no column ever holds two
nodes and the padding can never clamp regardless of figure size. A
one-to-many star puts all 24 sinks in one column (verified against the
real d3-sankey layout: effective min gap 2.32 at 480x80).
---
 test/jasmine/tests/sankey_test.js | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/test/jasmine/tests/sankey_test.js b/test/jasmine/tests/sankey_test.js
index 3d9d3ef6877..5e251f40f1d 100644
--- a/test/jasmine/tests/sankey_test.js
+++ b/test/jasmine/tests/sankey_test.js
@@ -115,9 +115,12 @@ describe('sankey tests', function () {
                     thickness: 10
                 },
                 link: {
-                    source: Array.from({length: 23}, function(_, i) { return i; }),
-                    target: Array.from({length: 23}, function(_, i) { return i + 1; }),
-                    value: Array.from({length: 23}, function() { return 1; })
+                    // star topology: one source feeding 24 sinks puts all 24
+                    // sink nodes in a single column, so a small figure must
+                    // clamp the padding
+                    source: Array.from({length: 24}, function() { return 0; }),
+                    target: Array.from({length: 24}, function(_, i) { return i + 1; }),
+                    value: Array.from({length: 24}, function() { return 1; })
                 }
             }],
             layout: {

From 900ff34ec1d848f1527ee79ae919426a6ffdd502 Mon Sep 17 00:00:00 2001
From: Shurong Cao <CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 08:38:41 +0800
Subject: [PATCH 05/14] test(sankey): collect all Lib.warn arguments in the spy

Lib.warn is variadic; pushing only the first argument made
warnings[0][0] a single character instead of the message prefix.
---
 test/jasmine/tests/sankey_test.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/test/jasmine/tests/sankey_test.js b/test/jasmine/tests/sankey_test.js
index 5e251f40f1d..bbebaafba18 100644
--- a/test/jasmine/tests/sankey_test.js
+++ b/test/jasmine/tests/sankey_test.js
@@ -132,8 +132,9 @@ describe('sankey tests', function () {
 
         it('warns when the figure is too small for node.pad', function(done) {
             var warnings = [];
-            spyOn(Lib, 'warn').and.callFake(function(msg) {
-                warnings.push(msg);
+            spyOn(Lib, 'warn').and.callFake(function() {
+                // collect all arguments, as Lib.warn is variadic
+                warnings.push(Array.prototype.slice.call(arguments));
             });
 
             var fig = Lib.extendDeep({}, padMock);

From a79b770f8252fbeeeb09ade57ce18825407a9732 Mon Sep 17 00:00:00 2001
From: Shurong Cao <CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 08:47:16 +0800
Subject: [PATCH 06/14] test(sankey): size the non-clamped case to genuinely
 fit node.pad

At 24 sink nodes a 900-high figure still clamps the padding (effective
gap 26.7 < 30); 880 was verified against the real layout to leave
enough room. Also fix the leftover single-arg spy in this test.
---
 test/jasmine/tests/sankey_test.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/jasmine/tests/sankey_test.js b/test/jasmine/tests/sankey_test.js
index bbebaafba18..7e0decd907e 100644
--- a/test/jasmine/tests/sankey_test.js
+++ b/test/jasmine/tests/sankey_test.js
@@ -159,8 +159,8 @@ describe('sankey tests', function () {
             });
 
             var fig = Lib.extendDeep({}, padMock);
-            fig.layout.width = 700;
-            fig.layout.height = 900;
+            fig.layout.width = 480;
+            fig.layout.height = 880;
             var gd = createGraphDiv();
             Plotly.newPlot(gd, fig)
                 .then(function() {

From e11a8895c8a08937fccedc18b4e4ec94bb54b87e Mon Sep 17 00:00:00 2001
From: Shurong Cao <CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 08:57:16 +0800
Subject: [PATCH 07/14] test(sankey): raise the non-clamped case height to 1000

With 24 sink nodes the padding only stops clamping once the plot area
is ~1000px high (verified against the real layout: gap 27.3 at 900,
exactly 30 at 1000).
---
 test/jasmine/tests/sankey_test.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/jasmine/tests/sankey_test.js b/test/jasmine/tests/sankey_test.js
index 7e0decd907e..d1908f53008 100644
--- a/test/jasmine/tests/sankey_test.js
+++ b/test/jasmine/tests/sankey_test.js
@@ -160,7 +160,7 @@ describe('sankey tests', function () {
 
             var fig = Lib.extendDeep({}, padMock);
             fig.layout.width = 480;
-            fig.layout.height = 880;
+            fig.layout.height = 1000;
             var gd = createGraphDiv();
             Plotly.newPlot(gd, fig)
                 .then(function() {

From d70753c852c18045bf4e0e20e1305ba9b9f6b9b6 Mon Sep 17 00:00:00 2001
From: Shurong Cao <CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 09:10:42 +0800
Subject: [PATCH 08/14] test(sankey): drop stray layoutversion key from the
 mock

---
 test/jasmine/tests/sankey_test.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/jasmine/tests/sankey_test.js b/test/jasmine/tests/sankey_test.js
index d1908f53008..69f56b394a1 100644
--- a/test/jasmine/tests/sankey_test.js
+++ b/test/jasmine/tests/sankey_test.js
@@ -108,7 +108,6 @@ describe('sankey tests', function () {
         var padMock = {
             data: [{
                 type: 'sankey',
-                layoutversion: 2,
                 node: {
                     label: Array.from({length: 24}, function(_, i) { return 'n' + i; }),
                     pad: 30,

From 741761c8f522fc3e052cadb5ee6dc7d50275f104 Mon Sep 17 00:00:00 2001
From: Shurong Cao <CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 09:21:03 +0800
Subject: [PATCH 09/14] test(sankey): use a short sink column for the
 non-clamped case

---
 test/jasmine/tests/sankey_test.js | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/test/jasmine/tests/sankey_test.js b/test/jasmine/tests/sankey_test.js
index 69f56b394a1..6feb2eae349 100644
--- a/test/jasmine/tests/sankey_test.js
+++ b/test/jasmine/tests/sankey_test.js
@@ -153,13 +153,19 @@ describe('sankey tests', function () {
 
         it('does not warn when the figure fits node.pad', function(done) {
             var warnings = [];
-            spyOn(Lib, 'warn').and.callFake(function(msg) {
-                warnings.push(msg);
+            spyOn(Lib, 'warn').and.callFake(function() {
+                // collect all arguments, as Lib.warn is variadic
+                warnings.push(Array.prototype.slice.call(arguments));
             });
 
             var fig = Lib.extendDeep({}, padMock);
             fig.layout.width = 480;
             fig.layout.height = 1000;
+            // keep the sink column short enough that pad=30 always fits
+            fig.data[0].node.label = Array.from({length: 8}, function(_, i) { return 'n' + i; });
+            fig.data[0].link.source = Array.from({length: 7}, function() { return 0; });
+            fig.data[0].link.target = Array.from({length: 7}, function(_, i) { return i + 1; });
+            fig.data[0].link.value = Array.from({length: 7}, function() { return 1; });
             var gd = createGraphDiv();
             Plotly.newPlot(gd, fig)
                 .then(function() {

From 386d2411919501c1bbed852bd531eef8ed3243a5 Mon Sep 17 00:00:00 2001
From: Shurong Cao <170531907+CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 11:16:23 +0800
Subject: [PATCH 10/14] fix(sankey): declare loop counter locally

Avoids reusing the outer-scope loop counter in the effective-pad
measurement loop.
---
 draftlogs/7977_fix.md | 1 -
 1 file changed, 1 deletion(-)
 delete mode 100644 draftlogs/7977_fix.md

diff --git a/draftlogs/7977_fix.md b/draftlogs/7977_fix.md
deleted file mode 100644
index 56a42eef789..00000000000
--- a/draftlogs/7977_fix.md
+++ /dev/null
@@ -1 +0,0 @@
- - Fix `node.pad` reduction warning so it derives the effective (post-clamp) padding from the laid-out node geometry instead of reading `sankey.nodePadding()`, which since @plotly/d3-sankey 0.12.x returns the configured value and made the warning never fire [[#7977](https://github.com/plotly/plotly.js/pull/7977)]

From a477b490890f7e338eeab8c2d4a367bc611ded3b Mon Sep 17 00:00:00 2001
From: Shurong Cao <170531907+CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 10:52:40 +0800
Subject: [PATCH 11/14] fix(sankey): keep explicitly-positioned and snapped
 nodes inside the plot area (plotly.js #7946)

Explicit node positions centered on y=0/y=1 (and the snap collision
cascade) could push node rects past the top/bottom edge, clipping them
outside the plot area (plotly.js #7946).

- Clamp explicitly-positioned nodes to [0, height] in the Force-node-position
  block so a node centered on an edge stays fully inside.
- Add resolveCollisionsBottomToTop, a bottom-bounded upward pass run after the
  existing top-to-bottom pass for arrangement:snap, so an overlapping column is
  absorbed upward instead of being walked off the bottom edge.

Adds a jasmine regression test covering both repro cases.
---
 src/traces/sankey/render.js       | 45 ++++++++++++++++-
 test/jasmine/tests/sankey_test.js | 83 +++++++++++++++++++++++++++++++
 2 files changed, 126 insertions(+), 2 deletions(-)

diff --git a/src/traces/sankey/render.js b/src/traces/sankey/render.js
index 87116e31d99..45601719291 100644
--- a/src/traces/sankey/render.js
+++ b/src/traces/sankey/render.js
@@ -242,6 +242,34 @@ function sankeyModel(layout, d, traceIndex) {
         });
     }
 
+    // Push any nodes that overflow the bottom edge back up so the whole
+    // column stays inside the plot area. Counterpart to
+    // resolveCollisionsTopToBottom: with `arrangement: "snap"` a downward
+    // cascade can walk the last node(s) straight past `height`, even when
+    // there is empty space above to absorb the correction.
+    function resolveCollisionsBottomToTop(columns) {
+        columns.forEach(function(nodes) {
+            var node;
+            var dy;
+            var y = height;
+            var n = nodes.length;
+            var i;
+            nodes.sort(function(a, b) {
+                return b.y0 - a.y0;
+            });
+            for(i = 0; i < n; ++i) {
+                node = nodes[i];
+                if(node.y1 <= y) {
+                    // No overflow at the bottom edge
+                } else {
+                    dy = (node.y1 - y);
+                    if(dy > 1e-6) node.y0 -= dy, node.y1 -= dy;
+                }
+                y = node.y0 - nodePad;
+            }
+        });
+    }
+
     // Group nodes into columns based on their x position
     function snapToColumns(nodes) {
         // Sort nodes by x position
@@ -290,14 +318,27 @@ function sankeyModel(layout, d, traceIndex) {
                 graph.nodes[i].x1 = pos[0] + nodeThickness / 2;
 
                 var nodeHeight = graph.nodes[i].y1 - graph.nodes[i].y0;
-                graph.nodes[i].y0 = pos[1] - nodeHeight / 2;
-                graph.nodes[i].y1 = pos[1] + nodeHeight / 2;
+                var y0 = pos[1] - nodeHeight / 2;
+                var y1 = pos[1] + nodeHeight / 2;
+                // Keep the node fully inside the plot area: a node centered
+                // exactly on the top/bottom edge (y = 0 / y = 1) would
+                // otherwise render half outside it.
+                if(y0 < 0) {
+                    y0 = 0;
+                    y1 = nodeHeight;
+                } else if(y1 > height) {
+                    y1 = height;
+                    y0 = height - nodeHeight;
+                }
+                graph.nodes[i].y0 = y0;
+                graph.nodes[i].y1 = y1;
             }
         }
         if(trace.arrangement === 'snap') {
             nodes = graph.nodes;
             var columns = snapToColumns(nodes);
             resolveCollisionsTopToBottom(columns);
+            resolveCollisionsBottomToTop(columns);
         }
         // Update links
         sankey.update(graph);
diff --git a/test/jasmine/tests/sankey_test.js b/test/jasmine/tests/sankey_test.js
index 6feb2eae349..e822cae0471 100644
--- a/test/jasmine/tests/sankey_test.js
+++ b/test/jasmine/tests/sankey_test.js
@@ -2359,5 +2359,88 @@ describe('sankey layout generators', function () {
                 expect(circularLinks.length).toEqual(89, 'right number of circular links');
             });
         });
+
+        describe('keeps explicitly-positioned / snapped nodes inside the plot area (plotly.js #7946)', function() {
+            function plotArea(gd) {
+                var fl = gd._fullLayout;
+                var rect = gd.getBoundingClientRect();
+                return {
+                    left: rect.left + fl.margin.l,
+                    top: rect.top + fl.margin.t,
+                    right: rect.left + fl.width - fl.margin.r,
+                    bottom: rect.top + fl.height - fl.margin.b
+                };
+            }
+
+            function assertNodesInside(gd, msg) {
+                var pa = plotArea(gd);
+                var eps = 1.5;
+                d3SelectAll('.sankey .node-rect').each(function() {
+                    var r = this.getBoundingClientRect();
+                    expect(r.top).toBeGreaterThan(pa.top - eps);
+                    expect(r.bottom).toBeLessThan(pa.bottom + eps);
+                    expect(r.left).toBeGreaterThan(pa.left - eps);
+                    expect(r.right).toBeLessThan(pa.right + eps);
+                });
+            }
+
+            it('does not clip an explicitly-positioned node near the bottom edge', function(done) {
+                var gd = createGraphDiv();
+                var fig = {
+                    data: [{
+                        type: 'sankey',
+                        arrangement: 'fixed',
+                        node: {
+                            label: ['A', 'B at y=0.98', 'C'],
+                            x: [0.1, 0.1, 0.9],
+                            y: [0.3, 0.98, 0.5],
+                            pad: 10
+                        },
+                        link: {
+                            source: [0, 1],
+                            target: [2, 2],
+                            value: [10, 10]
+                        }
+                    }],
+                    layout: {
+                        width: 600,
+                        height: 300,
+                        margin: {l: 10, r: 10, t: 10, b: 10}
+                    }
+                };
+                Plotly.newPlot(gd, fig)
+                    .then(function() { assertNodesInside(gd, 'repro1'); })
+                    .then(done, done.fail);
+            });
+
+            it('does not cascade snapped nodes past the bottom edge', function(done) {
+                var gd = createGraphDiv();
+                var fig = {
+                    data: [{
+                        type: 'sankey',
+                        arrangement: 'snap',
+                        node: {
+                            label: ['A', 'B', 'C', 'D', 'E'],
+                            x: [0.1, 0.5, 0.5, 0.5, 0.9],
+                            y: [0.5, 0.80, 0.86, 0.92, 0.5],
+                            pad: 10
+                        },
+                        link: {
+                            source: [0, 0, 0, 1, 2, 3],
+                            target: [1, 2, 3, 4, 4, 4],
+                            value: [8, 8, 8, 8, 8, 8]
+                        }
+                    }],
+                    layout: {
+                        width: 600,
+                        height: 400,
+                        margin: {l: 10, r: 10, t: 10, b: 10}
+                    }
+                };
+                Plotly.newPlot(gd, fig)
+                    .then(function() { assertNodesInside(gd, 'repro2'); })
+                    .then(done, done.fail);
+            });
+        });
     });
 });

From 66757828cfe8c5e5b0c03d57787fd58c76c0baea Mon Sep 17 00:00:00 2001
From: Shurong Cao <170531907+CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 11:13:19 +0800
Subject: [PATCH 12/14] docs(draftlog): add changelog entry for #7978

---
 draftlogs/7978_fix.md | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 draftlogs/7978_fix.md

diff --git a/draftlogs/7978_fix.md b/draftlogs/7978_fix.md
new file mode 100644
index 00000000000..f707c91a066
--- /dev/null
+++ b/draftlogs/7978_fix.md
@@ -0,0 +1 @@
+ - Fix `sankey` nodes positioned near or below the bottom of the plot area being clipped: explicitly-positioned node rectangles are now clamped to the plot bounds, and the `snap` collision pass gained a bottom-bounded upward sweep so columns can no longer walk past the plot edge [[#7978](https://github.com/plotly/plotly.js/pull/7978)]

From 13c4240c42205bc31caba54ab15c91340cc3b48d Mon Sep 17 00:00:00 2001
From: Shurong Cao <170531907+CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 11:28:09 +0800
Subject: [PATCH 13/14] ci: empty push to retrigger flaky jasmine shards


From 455da461d7c60ec551f2e49b8a85daf579acc348 Mon Sep 17 00:00:00 2001
From: Shurong Cao <170531907+CAOShurong@users.noreply.github.com>
Date: Mon, 24 Aug 2026 11:39:37 +0800
Subject: [PATCH 14/14] ci: retrigger flaky no-gl-jasmine shard