Fix "slice bounds out of range" error in memoryMetric.selectPoints()

[fedorlitau]

This will fix a bug which I have encountered while using nakabonne/ali (awesome! btw):

panic: runtime error: slice bounds out of range [6:1]

goroutine 53 [running]:in:

github.com/nakabonne/tstorage.(*memoryMetric).selectPoints(0xc0001ba7e0, 0x16a06b537e57044c, 0x16a06b5a7a7ab04c, 0x0, 0x0, 0x0)
        /root/go/pkg/mod/github.com/nakabonne/tstorage@v0.2.0/memory_partition.go:232 +0x27b
github.com/nakabonne/tstorage.(*memoryPartition).selectDataPoints(0xc000132200, 0x82dbf7, 0x7, 0x0, 0x0, 0x0, 0x16a06b537e57044c, 0x16a06b5a7a7ab04c, 0x449a4c, 0xc000092238, ...)
        /root/go/pkg/mod/github.com/nakabonne/tstorage@v0.2.0/memory_partition.go:124 +0x9e
github.com/nakabonne/tstorage.(*storage).Select(0xc000132180, 0x82dbf7, 0x7, 0x0, 0x0, 0x0, 0x16a06b537e57044c, 0x16a06b5a7a7ab04c, 0x46a77b, 0x77b3455e6fa8, ...)
        /root/go/pkg/mod/github.com/nakabonne/tstorage@v0.2.0/storage.go:324 +0x262
github.com/nakabonne/ali/storage.(*storage).Select(0xc00012e260, 0x82dbf7, 0x7, 0xc043adf3db12ae4c, 0x323d8539, 0xb456e0, 0xc043adfb5b12ae4c, 0x72e613139, 0xb456e0, 0x0, ...)
        /opt/ali/storage/storage.go:116 +0x105
github.com/nakabonne/ali/gui.(*drawer).redrawCharts(0xc0001c6480, 0x8a5ab8, 0xc00007e000)
        /opt/ali/gui/drawer.go:53 +0x262
created by github.com/nakabonne/ali/gui.attack
        /opt/ali/gui/keybinds.go:55 +0x9d

In the original code almost always the first case (green) is entered - the bug occurs when the second (red) case is executed:

[nakabonne]

@fedorlitau Thank you for your contribution! Sorry I got late. I'm in the middle of traveling so let me take a look later.

Btw, seems like your git commits aren't linked to your Github account (Ali's PR either). Because I want to accept you as a contributor, could you configure that setting if possible?

[fedorlitau]

@nakabonne Good point - I've corrected the commits on both PR's. Enjoy the traveling! ;-)

[nakabonne]

Well noticed! Thank you for working on this problem ;)

[nakabonne]

@fedorlitau In addition to that, could you add this test case to memory_partition_test.go?

diff --git a/memory_partition_test.go b/memory_partition_test.go
index 625d0bc..0e0701b 100644
--- a/memory_partition_test.go
+++ b/memory_partition_test.go
@@ -84,7 +84,43 @@ func Test_memoryPartition_SelectDataPoints(t *testing.T) {
                        want:            []*DataPoint{},
                },
                {
-                       name:   "select multiple points",
+                       name:   "select some points",
+                       metric: "metric1",
+                       start:  2,
+                       end:    4,
+                       memoryPartition: func() *memoryPartition {
+                               m := newMemoryPartition(nil, 0, "").(*memoryPartition)
+                               m.insertRows([]Row{
+                                       {
+                                               Metric:    "metric1",
+                                               DataPoint: DataPoint{Timestamp: 1, Value: 0.1},
+                                       },
+                                       {
+                                               Metric:    "metric1",
+                                               DataPoint: DataPoint{Timestamp: 2, Value: 0.1},
+                                       },
+                                       {
+                                               Metric:    "metric1",
+                                               DataPoint: DataPoint{Timestamp: 3, Value: 0.1},
+                                       },
+                                       {
+                                               Metric:    "metric1",
+                                               DataPoint: DataPoint{Timestamp: 4, Value: 0.1},
+                                       },
+                                       {
+                                               Metric:    "metric1",
+                                               DataPoint: DataPoint{Timestamp: 5, Value: 0.1},
+                                       },
+                               })
+                               return m
+                       }(),
+                       want: []*DataPoint{
+                               {Timestamp: 2, Value: 0.1},
+                               {Timestamp: 3, Value: 0.1},
+                       },
+               },
+               {
+                       name:   "select all points",
                        metric: "metric1",
                        start:  1,
                        end:    4,

[codecov-commenter]

Codecov Report

Merging #30 (b92d1c9) into main (9034eef) will increase coverage by 0.74%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #30      +/-   ##
==========================================
+ Coverage   65.35%   66.08%   +0.74%     
==========================================
  Files          19       19              
  Lines         955      955              
==========================================
+ Hits          624      631       +7     
+ Misses        234      229       -5     
+ Partials       97       95       -2     

Impacted Files	Coverage Δ
memory_partition.go	83.34% <100.00%> (+5.31%)	⬆️

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[nakabonne]

Great work!

[fedorlitau]

Thank you! And thank you for incorporating the fixes quicky and for: ali 💪😀