STYLE: Add [[nodiscard]] to non-const data(), begin(), end(), etc.

N-Dekker · N-Dekker · commit 13e653326a33 · 2025-12-12T18:49:59.000+01:00
The clang-tidy `modernize-use-nodiscard` check only considers _const_ member functions, whereas this commit specifically addresses non-const member functions. Follow-up to pull request InsightSoftwareConsortium#5404 commit 85aa7bd "STYLE: Use C++17 [[nodiscard]] attribute"
diff --git a/Modules/Core/Common/include/itkFixedArray.h b/Modules/Core/Common/include/itkFixedArray.h
@@ -324,7 +324,7 @@ class ITK_TEMPLATE_EXPORT FixedArray
     return m_InternalArray;
   }
 
-  ValueType *
+  [[nodiscard]] ValueType *
   data()
   {
     return m_InternalArray;
@@ -370,7 +370,7 @@ class ITK_TEMPLATE_EXPORT FixedArray
     return m_InternalArray;
   }
 
-  constexpr iterator
+  [[nodiscard]] constexpr iterator
   begin() noexcept
   {
     return m_InternalArray;
@@ -388,7 +388,7 @@ class ITK_TEMPLATE_EXPORT FixedArray
     return m_InternalArray + VLength;
   }
 
-  constexpr iterator
+  [[nodiscard]] constexpr iterator
   end() noexcept
   {
     return m_InternalArray + VLength;
@@ -400,7 +400,7 @@ class ITK_TEMPLATE_EXPORT FixedArray
     return this->cend();
   }
 
-  reverse_iterator
+  [[nodiscard]] reverse_iterator
   rbegin()
   {
     return reverse_iterator{ this->end() };
@@ -418,7 +418,7 @@ class ITK_TEMPLATE_EXPORT FixedArray
     return this->crbegin();
   }
 
-  reverse_iterator
+  [[nodiscard]] reverse_iterator
   rend()
   {
     return reverse_iterator{ this->begin() };
diff --git a/Modules/Core/Common/include/itkIndex.h b/Modules/Core/Common/include/itkIndex.h
@@ -355,7 +355,7 @@ struct ITK_TEMPLATE_EXPORT Index final
     return &m_InternalArray[0];
   }
 
-  constexpr iterator
+  [[nodiscard]] constexpr iterator
   begin()
   {
     return &m_InternalArray[0];
@@ -373,7 +373,7 @@ struct ITK_TEMPLATE_EXPORT Index final
     return &m_InternalArray[VDimension];
   }
 
-  constexpr iterator
+  [[nodiscard]] constexpr iterator
   end()
   {
     return &m_InternalArray[VDimension];
@@ -385,7 +385,7 @@ struct ITK_TEMPLATE_EXPORT Index final
     return &m_InternalArray[VDimension];
   }
 
-  reverse_iterator
+  [[nodiscard]] reverse_iterator
   rbegin()
   {
     return reverse_iterator(end());
@@ -397,7 +397,7 @@ struct ITK_TEMPLATE_EXPORT Index final
     return const_reverse_iterator(end());
   }
 
-  reverse_iterator
+  [[nodiscard]] reverse_iterator
   rend()
   {
     return reverse_iterator(begin());
@@ -453,7 +453,7 @@ struct ITK_TEMPLATE_EXPORT Index final
     return m_InternalArray[pos];
   }
 
-  constexpr reference
+  [[nodiscard]] constexpr reference
   front()
   {
     return *begin();
@@ -465,7 +465,7 @@ struct ITK_TEMPLATE_EXPORT Index final
     return *begin();
   }
 
-  constexpr reference
+  [[nodiscard]] constexpr reference
   back()
   {
     return VDimension ? *(end() - 1) : *end();
@@ -477,7 +477,7 @@ struct ITK_TEMPLATE_EXPORT Index final
     return VDimension ? *(end() - 1) : *end();
   }
 
-  IndexValueType *
+  [[nodiscard]] IndexValueType *
   data()
   {
     return &m_InternalArray[0];
diff --git a/Modules/Core/Common/include/itkMatrix.h b/Modules/Core/Common/include/itkMatrix.h
@@ -341,14 +341,14 @@ class ITK_TEMPLATE_EXPORT Matrix
   }
 
   /** Returns an iterator to the first element. */
-  iterator
+  [[nodiscard]] iterator
   begin()
   {
     return m_Matrix.begin();
   }
 
   /** Returns an iterator just beyond the last element. */
-  iterator
+  [[nodiscard]] iterator
   end()
   {
     return m_Matrix.end();
diff --git a/Modules/Core/Common/include/itkNeighborhoodAllocator.h b/Modules/Core/Common/include/itkNeighborhoodAllocator.h
@@ -120,7 +120,7 @@ class NeighborhoodAllocator
 
   /** STL-style iterator support for the memory buffer. */
   /** @ITKStartGrouping */
-  iterator
+  [[nodiscard]] iterator
   begin()
   {
     return m_Data.get();
@@ -130,7 +130,7 @@ class NeighborhoodAllocator
   {
     return m_Data.get();
   }
-  iterator
+  [[nodiscard]] iterator
   end()
   {
     return m_Data.get() + m_ElementCount;
@@ -173,7 +173,7 @@ class NeighborhoodAllocator
     }
   }
 
-  TPixel *
+  [[nodiscard]] TPixel *
   data() noexcept
   {
     return m_Data.get();
diff --git a/Modules/Core/Common/include/itkOffset.h b/Modules/Core/Common/include/itkOffset.h
@@ -304,7 +304,7 @@ struct ITK_TEMPLATE_EXPORT Offset final
     return &m_InternalArray[0];
   }
 
-  constexpr iterator
+  [[nodiscard]] constexpr iterator
   begin()
   {
     return &m_InternalArray[0];
@@ -322,7 +322,7 @@ struct ITK_TEMPLATE_EXPORT Offset final
     return &m_InternalArray[VDimension];
   }
 
-  constexpr iterator
+  [[nodiscard]] constexpr iterator
   end()
   {
     return &m_InternalArray[VDimension];
@@ -334,7 +334,7 @@ struct ITK_TEMPLATE_EXPORT Offset final
     return &m_InternalArray[VDimension];
   }
 
-  reverse_iterator
+  [[nodiscard]] reverse_iterator
   rbegin()
   {
     return reverse_iterator(end());
@@ -346,7 +346,7 @@ struct ITK_TEMPLATE_EXPORT Offset final
     return const_reverse_iterator(end());
   }
 
-  reverse_iterator
+  [[nodiscard]] reverse_iterator
   rend()
   {
     return reverse_iterator(begin());
@@ -402,7 +402,7 @@ struct ITK_TEMPLATE_EXPORT Offset final
     return m_InternalArray[pos];
   }
 
-  constexpr reference
+  [[nodiscard]] constexpr reference
   front()
   {
     return *begin();
@@ -414,7 +414,7 @@ struct ITK_TEMPLATE_EXPORT Offset final
     return *begin();
   }
 
-  constexpr reference
+  [[nodiscard]] constexpr reference
   back()
   {
     return VDimension ? *(end() - 1) : *end();
@@ -426,7 +426,7 @@ struct ITK_TEMPLATE_EXPORT Offset final
     return VDimension ? *(end() - 1) : *end();
   }
 
-  OffsetValueType *
+  [[nodiscard]] OffsetValueType *
   data()
   {
     return &m_InternalArray[0];
diff --git a/Modules/Core/Common/include/itkSize.h b/Modules/Core/Common/include/itkSize.h
@@ -279,7 +279,7 @@ struct ITK_TEMPLATE_EXPORT Size final
     return &m_InternalArray[0];
   }
 
-  constexpr iterator
+  [[nodiscard]] constexpr iterator
   begin()
   {
     return &m_InternalArray[0];
@@ -297,7 +297,7 @@ struct ITK_TEMPLATE_EXPORT Size final
     return &m_InternalArray[VDimension];
   }
 
-  constexpr iterator
+  [[nodiscard]] constexpr iterator
   end()
   {
     return &m_InternalArray[VDimension];
@@ -309,7 +309,7 @@ struct ITK_TEMPLATE_EXPORT Size final
     return &m_InternalArray[VDimension];
   }
 
-  reverse_iterator
+  [[nodiscard]] reverse_iterator
   rbegin()
   {
     return reverse_iterator(end());
@@ -321,7 +321,7 @@ struct ITK_TEMPLATE_EXPORT Size final
     return const_reverse_iterator(end());
   }
 
-  reverse_iterator
+  [[nodiscard]] reverse_iterator
   rend()
   {
     return reverse_iterator(begin());
@@ -377,7 +377,7 @@ struct ITK_TEMPLATE_EXPORT Size final
     return m_InternalArray[pos];
   }
 
-  constexpr reference
+  [[nodiscard]] constexpr reference
   front()
   {
     return *begin();
@@ -389,7 +389,7 @@ struct ITK_TEMPLATE_EXPORT Size final
     return *begin();
   }
 
-  constexpr reference
+  [[nodiscard]] constexpr reference
   back()
   {
     return VDimension ? *(end() - 1) : *end();
@@ -401,7 +401,7 @@ struct ITK_TEMPLATE_EXPORT Size final
     return VDimension ? *(end() - 1) : *end();
   }
 
-  SizeValueType *
+  [[nodiscard]] SizeValueType *
   data()
   {
     return &m_InternalArray[0];
diff --git a/Modules/IO/IPL/include/itkIPLFileNameList.h b/Modules/IO/IPL/include/itkIPLFileNameList.h
@@ -139,13 +139,13 @@ class ITKIOIPL_EXPORT IPLFileNameList
 
   virtual ~IPLFileNameList();
 
-  IteratorType
+  [[nodiscard]] IteratorType
   begin()
   {
     return m_List.begin();
   }
 
-  IteratorType
+  [[nodiscard]] IteratorType
   end()
   {
     return m_List.end();

Original file line number	Diff line number	Diff line change
`@@ -324,7 +324,7 @@ class ITK_TEMPLATE_EXPORT FixedArray`
`324`	`324`	`return m_InternalArray;`
`325`	`325`	`}`
`326`	`326`
`327`		`- ValueType *`
	`327`	`+ [[nodiscard]] ValueType *`
`328`	`328`	`data()`
`329`	`329`	`{`
`330`	`330`	`return m_InternalArray;`
`@@ -370,7 +370,7 @@ class ITK_TEMPLATE_EXPORT FixedArray`
`370`	`370`	`return m_InternalArray;`
`371`	`371`	`}`
`372`	`372`
`373`		`- constexpr iterator`
	`373`	`+ [[nodiscard]] constexpr iterator`
`374`	`374`	`begin() noexcept`
`375`	`375`	`{`
`376`	`376`	`return m_InternalArray;`
`@@ -388,7 +388,7 @@ class ITK_TEMPLATE_EXPORT FixedArray`
`388`	`388`	`return m_InternalArray + VLength;`
`389`	`389`	`}`
`390`	`390`
`391`		`- constexpr iterator`
	`391`	`+ [[nodiscard]] constexpr iterator`
`392`	`392`	`end() noexcept`
`393`	`393`	`{`
`394`	`394`	`return m_InternalArray + VLength;`
`@@ -400,7 +400,7 @@ class ITK_TEMPLATE_EXPORT FixedArray`
`400`	`400`	`return this->cend();`
`401`	`401`	`}`
`402`	`402`
`403`		`- reverse_iterator`
	`403`	`+ [[nodiscard]] reverse_iterator`
`404`	`404`	`rbegin()`
`405`	`405`	`{`
`406`	`406`	`return reverse_iterator{ this->end() };`
`@@ -418,7 +418,7 @@ class ITK_TEMPLATE_EXPORT FixedArray`
`418`	`418`	`return this->crbegin();`
`419`	`419`	`}`
`420`	`420`
`421`		`- reverse_iterator`
	`421`	`+ [[nodiscard]] reverse_iterator`
`422`	`422`	`rend()`
`423`	`423`	`{`
`424`	`424`	`return reverse_iterator{ this->begin() };`
Original file line number	Diff line number	Diff line change
`@@ -355,7 +355,7 @@ struct ITK_TEMPLATE_EXPORT Index final`
`355`	`355`	`return &m_InternalArray[0];`
`356`	`356`	`}`
`357`	`357`
`358`		`- constexpr iterator`
	`358`	`+ [[nodiscard]] constexpr iterator`
`359`	`359`	`begin()`
`360`	`360`	`{`
`361`	`361`	`return &m_InternalArray[0];`
`@@ -373,7 +373,7 @@ struct ITK_TEMPLATE_EXPORT Index final`
`373`	`373`	`return &m_InternalArray[VDimension];`
`374`	`374`	`}`
`375`	`375`
`376`		`- constexpr iterator`
	`376`	`+ [[nodiscard]] constexpr iterator`
`377`	`377`	`end()`
`378`	`378`	`{`
`379`	`379`	`return &m_InternalArray[VDimension];`
`@@ -385,7 +385,7 @@ struct ITK_TEMPLATE_EXPORT Index final`
`385`	`385`	`return &m_InternalArray[VDimension];`
`386`	`386`	`}`
`387`	`387`
`388`		`- reverse_iterator`
	`388`	`+ [[nodiscard]] reverse_iterator`
`389`	`389`	`rbegin()`
`390`	`390`	`{`
`391`	`391`	`return reverse_iterator(end());`
`@@ -397,7 +397,7 @@ struct ITK_TEMPLATE_EXPORT Index final`
`397`	`397`	`return const_reverse_iterator(end());`
`398`	`398`	`}`
`399`	`399`
`400`		`- reverse_iterator`
	`400`	`+ [[nodiscard]] reverse_iterator`
`401`	`401`	`rend()`
`402`	`402`	`{`
`403`	`403`	`return reverse_iterator(begin());`
`@@ -453,7 +453,7 @@ struct ITK_TEMPLATE_EXPORT Index final`
`453`	`453`	`return m_InternalArray[pos];`
`454`	`454`	`}`
`455`	`455`
`456`		`- constexpr reference`
	`456`	`+ [[nodiscard]] constexpr reference`
`457`	`457`	`front()`
`458`	`458`	`{`
`459`	`459`	`return *begin();`
`@@ -465,7 +465,7 @@ struct ITK_TEMPLATE_EXPORT Index final`
`465`	`465`	`return *begin();`
`466`	`466`	`}`
`467`	`467`
`468`		`- constexpr reference`
	`468`	`+ [[nodiscard]] constexpr reference`
`469`	`469`	`back()`
`470`	`470`	`{`
`471`	`471`	`return VDimension ? (end() - 1) : end();`
`@@ -477,7 +477,7 @@ struct ITK_TEMPLATE_EXPORT Index final`
`477`	`477`	`return VDimension ? (end() - 1) : end();`
`478`	`478`	`}`
`479`	`479`
`480`		`- IndexValueType *`
	`480`	`+ [[nodiscard]] IndexValueType *`
`481`	`481`	`data()`
`482`	`482`	`{`
`483`	`483`	`return &m_InternalArray[0];`
Original file line number	Diff line number	Diff line change
`@@ -341,14 +341,14 @@ class ITK_TEMPLATE_EXPORT Matrix`
`341`	`341`	`}`
`342`	`342`
`343`	`343`	`/** Returns an iterator to the first element. */`
`344`		`- iterator`
	`344`	`+ [[nodiscard]] iterator`
`345`	`345`	`begin()`
`346`	`346`	`{`
`347`	`347`	`return m_Matrix.begin();`
`348`	`348`	`}`
`349`	`349`
`350`	`350`	`/** Returns an iterator just beyond the last element. */`
`351`		`- iterator`
	`351`	`+ [[nodiscard]] iterator`
`352`	`352`	`end()`
`353`	`353`	`{`
`354`	`354`	`return m_Matrix.end();`
Original file line number	Diff line number	Diff line change
`@@ -120,7 +120,7 @@ class NeighborhoodAllocator`
`120`	`120`
`121`	`121`	`/** STL-style iterator support for the memory buffer. */`
`122`	`122`	`/** @ITKStartGrouping */`
`123`		`- iterator`
	`123`	`+ [[nodiscard]] iterator`
`124`	`124`	`begin()`
`125`	`125`	`{`
`126`	`126`	`return m_Data.get();`
`@@ -130,7 +130,7 @@ class NeighborhoodAllocator`
`130`	`130`	`{`
`131`	`131`	`return m_Data.get();`
`132`	`132`	`}`
`133`		`- iterator`
	`133`	`+ [[nodiscard]] iterator`
`134`	`134`	`end()`
`135`	`135`	`{`
`136`	`136`	`return m_Data.get() + m_ElementCount;`
`@@ -173,7 +173,7 @@ class NeighborhoodAllocator`
`173`	`173`	`}`
`174`	`174`	`}`
`175`	`175`
`176`		`- TPixel *`
	`176`	`+ [[nodiscard]] TPixel *`
`177`	`177`	`data() noexcept`
`178`	`178`	`{`
`179`	`179`	`return m_Data.get();`
Original file line number	Diff line number	Diff line change
`@@ -304,7 +304,7 @@ struct ITK_TEMPLATE_EXPORT Offset final`
`304`	`304`	`return &m_InternalArray[0];`
`305`	`305`	`}`
`306`	`306`
`307`		`- constexpr iterator`
	`307`	`+ [[nodiscard]] constexpr iterator`
`308`	`308`	`begin()`
`309`	`309`	`{`
`310`	`310`	`return &m_InternalArray[0];`
`@@ -322,7 +322,7 @@ struct ITK_TEMPLATE_EXPORT Offset final`
`322`	`322`	`return &m_InternalArray[VDimension];`
`323`	`323`	`}`
`324`	`324`
`325`		`- constexpr iterator`
	`325`	`+ [[nodiscard]] constexpr iterator`
`326`	`326`	`end()`
`327`	`327`	`{`
`328`	`328`	`return &m_InternalArray[VDimension];`
`@@ -334,7 +334,7 @@ struct ITK_TEMPLATE_EXPORT Offset final`
`334`	`334`	`return &m_InternalArray[VDimension];`
`335`	`335`	`}`
`336`	`336`
`337`		`- reverse_iterator`
	`337`	`+ [[nodiscard]] reverse_iterator`
`338`	`338`	`rbegin()`
`339`	`339`	`{`
`340`	`340`	`return reverse_iterator(end());`
`@@ -346,7 +346,7 @@ struct ITK_TEMPLATE_EXPORT Offset final`
`346`	`346`	`return const_reverse_iterator(end());`
`347`	`347`	`}`
`348`	`348`
`349`		`- reverse_iterator`
	`349`	`+ [[nodiscard]] reverse_iterator`
`350`	`350`	`rend()`
`351`	`351`	`{`
`352`	`352`	`return reverse_iterator(begin());`
`@@ -402,7 +402,7 @@ struct ITK_TEMPLATE_EXPORT Offset final`
`402`	`402`	`return m_InternalArray[pos];`
`403`	`403`	`}`
`404`	`404`
`405`		`- constexpr reference`
	`405`	`+ [[nodiscard]] constexpr reference`
`406`	`406`	`front()`
`407`	`407`	`{`
`408`	`408`	`return *begin();`
`@@ -414,7 +414,7 @@ struct ITK_TEMPLATE_EXPORT Offset final`
`414`	`414`	`return *begin();`
`415`	`415`	`}`
`416`	`416`
`417`		`- constexpr reference`
	`417`	`+ [[nodiscard]] constexpr reference`
`418`	`418`	`back()`
`419`	`419`	`{`
`420`	`420`	`return VDimension ? (end() - 1) : end();`
`@@ -426,7 +426,7 @@ struct ITK_TEMPLATE_EXPORT Offset final`
`426`	`426`	`return VDimension ? (end() - 1) : end();`
`427`	`427`	`}`
`428`	`428`
`429`		`- OffsetValueType *`
	`429`	`+ [[nodiscard]] OffsetValueType *`
`430`	`430`	`data()`
`431`	`431`	`{`
`432`	`432`	`return &m_InternalArray[0];`
Original file line number	Diff line number	Diff line change
`@@ -279,7 +279,7 @@ struct ITK_TEMPLATE_EXPORT Size final`
`279`	`279`	`return &m_InternalArray[0];`
`280`	`280`	`}`
`281`	`281`
`282`		`- constexpr iterator`
	`282`	`+ [[nodiscard]] constexpr iterator`
`283`	`283`	`begin()`
`284`	`284`	`{`
`285`	`285`	`return &m_InternalArray[0];`
`@@ -297,7 +297,7 @@ struct ITK_TEMPLATE_EXPORT Size final`
`297`	`297`	`return &m_InternalArray[VDimension];`
`298`	`298`	`}`
`299`	`299`
`300`		`- constexpr iterator`
	`300`	`+ [[nodiscard]] constexpr iterator`
`301`	`301`	`end()`
`302`	`302`	`{`
`303`	`303`	`return &m_InternalArray[VDimension];`
`@@ -309,7 +309,7 @@ struct ITK_TEMPLATE_EXPORT Size final`
`309`	`309`	`return &m_InternalArray[VDimension];`
`310`	`310`	`}`
`311`	`311`
`312`		`- reverse_iterator`
	`312`	`+ [[nodiscard]] reverse_iterator`
`313`	`313`	`rbegin()`
`314`	`314`	`{`
`315`	`315`	`return reverse_iterator(end());`
`@@ -321,7 +321,7 @@ struct ITK_TEMPLATE_EXPORT Size final`
`321`	`321`	`return const_reverse_iterator(end());`
`322`	`322`	`}`
`323`	`323`
`324`		`- reverse_iterator`
	`324`	`+ [[nodiscard]] reverse_iterator`
`325`	`325`	`rend()`
`326`	`326`	`{`
`327`	`327`	`return reverse_iterator(begin());`
`@@ -377,7 +377,7 @@ struct ITK_TEMPLATE_EXPORT Size final`
`377`	`377`	`return m_InternalArray[pos];`
`378`	`378`	`}`
`379`	`379`
`380`		`- constexpr reference`
	`380`	`+ [[nodiscard]] constexpr reference`
`381`	`381`	`front()`
`382`	`382`	`{`
`383`	`383`	`return *begin();`
`@@ -389,7 +389,7 @@ struct ITK_TEMPLATE_EXPORT Size final`
`389`	`389`	`return *begin();`
`390`	`390`	`}`
`391`	`391`
`392`		`- constexpr reference`
	`392`	`+ [[nodiscard]] constexpr reference`
`393`	`393`	`back()`
`394`	`394`	`{`
`395`	`395`	`return VDimension ? (end() - 1) : end();`
`@@ -401,7 +401,7 @@ struct ITK_TEMPLATE_EXPORT Size final`
`401`	`401`	`return VDimension ? (end() - 1) : end();`
`402`	`402`	`}`
`403`	`403`
`404`		`- SizeValueType *`
	`404`	`+ [[nodiscard]] SizeValueType *`
`405`	`405`	`data()`
`406`	`406`	`{`
`407`	`407`	`return &m_InternalArray[0];`
Original file line number	Diff line number	Diff line change
`@@ -139,13 +139,13 @@ class ITKIOIPL_EXPORT IPLFileNameList`
`139`	`139`
`140`	`140`	`virtual ~IPLFileNameList();`
`141`	`141`
`142`		`- IteratorType`
	`142`	`+ [[nodiscard]] IteratorType`
`143`	`143`	`begin()`
`144`	`144`	`{`
`145`	`145`	`return m_List.begin();`
`146`	`146`	`}`
`147`	`147`
`148`		`- IteratorType`
	`148`	`+ [[nodiscard]] IteratorType`
`149`	`149`	`end()`
`150`	`150`	`{`
`151`	`151`	`return m_List.end();`