Don't assume string_view::iterator is const char*

There were a few assumptions in the code that these types are equivalent,
but they are not on all platforms.

The fixes sometimes involve ugly `&*some_iterator` constructs to get to
the underlying location. Some of these should be re-considered after
switching to c++20.

Issues: chipsalliance#2323

Author: hzeller

.github/workflows/verible-ci.yml

@@ -313,7 +313,7 @@ jobs:
 
     - name: Install Dependencies
       run: |
-        echo "USE_BAZEL_VERSION=6.5.0" >> $GITHUB_ENV
+        echo "USE_BAZEL_VERSION=7.4.1" >> $GITHUB_ENV
 
     - name: Checkout code
       uses: actions/checkout@v3
@@ -390,7 +390,7 @@ jobs:
 
     - name: Install dependencies
       run: |
-        choco install bazel --force --version=6.5.0
+        choco install bazel --force --version=7.4.1
         choco install winflexbison3
         choco install llvm --allow-downgrade --version=17.0.6
 

MODULE.bazel

@@ -19,13 +19,7 @@ bazel_dep(name = "rules_bison", version = "0.3")
 # depends on it :( -- to support all active bazel's, we're stuck till EOL bazel6
 bazel_dep(name = "googletest", version = "1.14.0.bcr.1", dev_dependency = True)
 
-bazel_dep(name = "abseil-cpp", version = "20240116.2")
-single_version_override(
-    module_name = "abseil-cpp",
-    patch_strip = 1,
-    patches = ["//bazel:absl.patch"],
-    version = "20240116.2",
-)
+bazel_dep(name = "abseil-cpp", version = "20240722.0.bcr.2")
 
 # Last protobuf version working with windows without strange linking errors.
 # This also means that we unfortunately can't use the @protobuf//bazel rules

bazel/absl.patch

@@ -47,12 +47,12 @@ std::string AutoFix::Apply(absl::string_view base) const {
     CHECK_GE(base.cend(), edit.fragment.cend());
 
     const absl::string_view text_before(
-        prev_start, std::distance(prev_start, edit.fragment.cbegin()));
+        &*prev_start, std::distance(prev_start, edit.fragment.cbegin()));
     absl::StrAppend(&result, text_before, edit.replacement);
 
     prev_start = edit.fragment.cend();
   }
-  const absl::string_view text_after(prev_start,
+  const absl::string_view text_after(&*prev_start,
                                      std::distance(prev_start, base.cend()));
   return absl::StrCat(result, text_after);
 }

verible/common/analysis/lint-rule-status.cc

@@ -153,6 +153,7 @@ cc_library(
         "//verible/common/util:vector-tree",
         "@abseil-cpp//absl/container:fixed_array",
         "@abseil-cpp//absl/log",
+        "@abseil-cpp//absl/log:vlog_is_on",
         "@abseil-cpp//absl/strings",
         "@abseil-cpp//absl/strings:string_view",
     ],

verible/common/formatting/BUILD

@@ -69,7 +69,8 @@ class AlignmentTestFixture : public ::testing::Test,
                              public UnwrappedLineMemoryHandler {
  public:
   explicit AlignmentTestFixture(absl::string_view text)
-      : sample_(text),
+      : sample_backing_(text),
+        sample_(sample_backing_),
         tokens_(absl::StrSplit(sample_, absl::ByAnyChar(" \n"),
                                absl::SkipEmpty())) {
     for (const auto token : tokens_) {
@@ -80,7 +81,8 @@ class AlignmentTestFixture : public ::testing::Test,
   }
 
  protected:
-  const std::string sample_;
+  const std::string sample_backing_;
+  const absl::string_view sample_;
   const std::vector<absl::string_view> tokens_;
   std::vector<TokenInfo> ftokens_;
 };
@@ -271,7 +273,7 @@ TEST_F(Sparse3x3MatrixAlignmentTest, AlignmentPolicyFlushLeft) {
 
 TEST_F(Sparse3x3MatrixAlignmentTest, AlignmentPolicyPreserve) {
   // Set previous-token string pointers to preserve spaces.
-  ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+  ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                              &pre_format_tokens_);
 
   TabularAlignTokens(40, sample_, ByteOffsetSet(), kPreserveAlignmentHandler,
@@ -391,7 +393,7 @@ TEST_F(Sparse3x3MatrixAlignmentTest, IgnoreCommentLine) {
 
 TEST_F(Sparse3x3MatrixAlignmentTest, CompletelyDisabledNoAlignment) {
   // Disabled ranges use original spacing
-  ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+  ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                              &pre_format_tokens_);
 
   // Require 1 space between tokens.
@@ -413,7 +415,7 @@ TEST_F(Sparse3x3MatrixAlignmentTest, CompletelyDisabledNoAlignment) {
 
 TEST_F(Sparse3x3MatrixAlignmentTest, CompletelyDisabledNoAlignmentWithIndent) {
   // Disabled ranges use original spacing
-  ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+  ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                              &pre_format_tokens_);
 
   // Require 1 space between tokens.
@@ -445,7 +447,7 @@ class Sparse3x3MatrixAlignmentMoreSpacesTest
   Sparse3x3MatrixAlignmentMoreSpacesTest()
       : Sparse3x3MatrixAlignmentTest("one   two\nthree   four\nfive   six") {
     // This is needed for preservation of original spacing.
-    ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+    ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                                &pre_format_tokens_);
   }
 };
@@ -480,7 +482,7 @@ TEST_F(Sparse3x3MatrixAlignmentMoreSpacesTest,
 
 TEST_F(Sparse3x3MatrixAlignmentTest, PartiallyDisabledNoAlignment) {
   // Disabled ranges use original spacing
-  ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+  ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                              &pre_format_tokens_);
 
   // Require 1 space between tokens.
@@ -865,7 +867,7 @@ class Dense2x2MatrixAlignmentTest : public MatrixTreeAlignmentTestFixture {
     CHECK_EQ(tokens_.size(), 4);
 
     // Need to know original spacing to be able to infer user-intent.
-    ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+    ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                                &pre_format_tokens_);
 
     // Require 1 space between tokens.
@@ -1170,7 +1172,7 @@ TEST_F(SubcolumnsTreeAlignmentTest, AlignmentPolicyFlushLeft) {
 }
 
 TEST_F(SubcolumnsTreeAlignmentTest, AlignmentPolicyPreserve) {
-  ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+  ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                              &pre_format_tokens_);
 
   TabularAlignTokens(40, sample_, ByteOffsetSet(),
@@ -1332,7 +1334,7 @@ class InferSubcolumnsTreeAlignmentTest : public SubcolumnsTreeAlignmentTest {
           "( eleven  nineteen-ninety-nine  2k    )\n")
       : SubcolumnsTreeAlignmentTest(text) {
     // Need to know original spacing to be able to infer user-intent.
-    ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+    ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                                &pre_format_tokens_);
 
     // Require 1 space between tokens.
@@ -1497,15 +1499,16 @@ class FormatUsingOriginalSpacingTest : public ::testing::Test,
           "\n       <1NL+7Spaces>\n       <1nl+7spaces>"
           "\n\n  <2NL+2Spaces>\n\n  <2nl+2spaces>"
           "\n \n\n  <1NL+1Space+2NL+2Spaces>\n \n\n  <1nl+1space+2nl+2spaces>")
-      : sample_(text),
+      : sample_backing_(text),
+        sample_(sample_backing_),
         tokens_(absl::StrSplit(sample_, OutsideCharPairs('<', '>'),
                                absl::SkipEmpty())) {
     for (const auto token : tokens_) {
       ftokens_.emplace_back(1, token);
     }
     // sample_ is the memory-owning string buffer
     CreateTokenInfosExternalStringBuffer(ftokens_);
-    ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+    ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                                &pre_format_tokens_);
   }
 
@@ -1518,7 +1521,8 @@ class FormatUsingOriginalSpacingTest : public ::testing::Test,
     EXPECT_PRED_FORMAT2(TokenPartitionTreesEqualPredFormat, nodes[0], expected);
   }
 
-  const std::string sample_;
+  const std::string sample_backing_;
+  const absl::string_view sample_;
   const std::vector<absl::string_view> tokens_;
   std::vector<TokenInfo> ftokens_;
 };

verible/common/formatting/align_test.cc

@@ -77,8 +77,8 @@ std::ostream &operator<<(std::ostream &stream, const InterTokenInfo &t) {
   stream << "{\n  spaces_required: " << t.spaces_required
          << "\n  break_penalty: " << t.break_penalty
          << "\n  break_decision: " << t.break_decision
-         << "\n  preserve_space?: " << (t.preserved_space_start != nullptr)
-         << "\n}";
+         << "\n  preserve_space?: "
+         << (t.preserved_space_start != string_view_null_iterator()) << "\n}";
   return stream;
 }
 
@@ -143,9 +143,10 @@ InterTokenDecision::InterTokenDecision(const InterTokenInfo &info)
       action(ConvertSpacing(info.break_decision)),
       preserved_space_start(info.preserved_space_start) {}
 
-static absl::string_view OriginalLeadingSpacesRange(const char *begin,
-                                                    const char *end) {
-  if (begin == nullptr) {
+static absl::string_view OriginalLeadingSpacesRange(
+    absl::string_view::const_iterator begin,
+    absl::string_view::const_iterator end) {
+  if (begin == string_view_null_iterator()) {
     VLOG(4) << "no original space range";
     return make_string_view_range(end, end);  // empty range
   }
@@ -163,7 +164,7 @@ absl::string_view FormattedToken::OriginalLeadingSpaces() const {
 std::ostream &FormattedToken::FormattedText(std::ostream &stream) const {
   switch (before.action) {
     case SpacingDecision::kPreserve: {
-      if (before.preserved_space_start != nullptr) {
+      if (before.preserved_space_start != string_view_null_iterator()) {
         // Calculate string_view range of pre-existing spaces, and print that.
         stream << OriginalLeadingSpaces();
       } else {
@@ -196,15 +197,15 @@ absl::string_view PreFormatToken::OriginalLeadingSpaces() const {
 
 size_t PreFormatToken::LeadingSpacesLength() const {
   if (before.break_decision == SpacingOptions::kPreserve &&
-      before.preserved_space_start != nullptr) {
+      before.preserved_space_start != string_view_null_iterator()) {
     return OriginalLeadingSpaces().length();
   }
   // in other cases (append, wrap), take the spaces_required value.
   return before.spaces_required;
 }
 
 int PreFormatToken::ExcessSpaces() const {
-  if (before.preserved_space_start == nullptr) return 0;
+  if (before.preserved_space_start == string_view_null_iterator()) return 0;
   const absl::string_view leading_spaces = OriginalLeadingSpaces();
   int delta = 0;
   if (!absl::StrContains(leading_spaces, "\n")) {
@@ -228,9 +229,10 @@ std::ostream &operator<<(std::ostream &stream, const PreFormatToken &t) {
 }
 
 void ConnectPreFormatTokensPreservedSpaceStarts(
-    const char *buffer_start, std::vector<PreFormatToken> *format_tokens) {
+    absl::string_view::const_iterator buffer_start,
+    std::vector<PreFormatToken> *format_tokens) {
   VLOG(4) << __FUNCTION__;
-  CHECK(buffer_start != nullptr);
+  CHECK(buffer_start != string_view_null_iterator());
   for (auto &ftoken : *format_tokens) {
     ftoken.before.preserved_space_start = buffer_start;
     VLOG(4) << "space: " << VisualizeWhitespace(ftoken.OriginalLeadingSpaces());

verible/common/formatting/format-token.cc

@@ -28,6 +28,10 @@
 
 namespace verible {
 
+// TODO: find something platform independent that is less ugly.
+inline absl::string_view::iterator string_view_null_iterator() {
+  return absl::string_view().begin();
+}
 // Enumeration for options for formatting spaces between tokens.
 // This controls what to explore (if not pre-determined).
 // Related enum: SpacingDecision
@@ -76,7 +80,8 @@ struct InterTokenInfo {
   // tokens, for the sake of preserving space.
   // Together with the current token, they can form a string_view representing
   // pre-existing space from the original buffer.
-  const char *preserved_space_start = nullptr;
+  absl::string_view::iterator preserved_space_start =
+      string_view_null_iterator();
 
   InterTokenInfo() = default;
   InterTokenInfo(const InterTokenInfo &) = default;
@@ -158,7 +163,7 @@ std::ostream &operator<<(std::ostream &stream, const PreFormatToken &token);
 // inter-token (space) text.
 // Note that this does not cover the space between the last token and EOF.
 void ConnectPreFormatTokensPreservedSpaceStarts(
-    const char *buffer_start,
+    absl::string_view::const_iterator buffer_start,
     std::vector<verible::PreFormatToken> *format_tokens);
 
 // Marks formatting-disabled ranges of tokens so that their original spacing is
@@ -199,7 +204,8 @@ struct InterTokenDecision {
   SpacingDecision action = SpacingDecision::kPreserve;
 
   // When preserving spaces before this token, start from this offset.
-  const char *preserved_space_start = nullptr;
+  absl::string_view::iterator preserved_space_start =
+      string_view_null_iterator();
 
   InterTokenDecision() = default;
 

verible/common/formatting/format-token.h

@@ -218,9 +218,9 @@ class ConnectPreFormatTokensPreservedSpaceStartsTest
       public UnwrappedLineMemoryHandler {};
 
 TEST_F(ConnectPreFormatTokensPreservedSpaceStartsTest, Empty) {
-  const char *text = "";
+  constexpr absl::string_view text;
   CreateTokenInfosExternalStringBuffer({});
-  ConnectPreFormatTokensPreservedSpaceStarts(text, &pre_format_tokens_);
+  ConnectPreFormatTokensPreservedSpaceStarts(text.begin(), &pre_format_tokens_);
   EXPECT_TRUE(pre_format_tokens_.empty());
 }
 

verible/common/formatting/format-token_test.cc

@@ -30,6 +30,7 @@
 
 #include "absl/container/fixed_array.h"
 #include "absl/log/log.h"
+#include "absl/log/vlog_is_on.h"
 #include "verible/common/formatting/basic-format-style.h"
 #include "verible/common/formatting/layout-optimizer-internal.h"
 #include "verible/common/formatting/token-partition-tree.h"

verible/common/formatting/layout-optimizer.cc

@@ -701,7 +701,8 @@ class LayoutFunctionFactoryTest : public ::testing::Test,
     // Setup pointers for OriginalLeadingSpaces()
     auto must_wrap_token = must_wrap_pre_format_tokens.begin();
     auto joinable_token = joinable_pre_format_tokens.begin();
-    const char *buffer_start = sample_.data();
+    absl::string_view sample_view(sample_);
+    absl::string_view::const_iterator buffer_start = sample_view.begin();
     for (size_t i = 0; i < number_of_tokens_in_set; ++i) {
       must_wrap_token->before.preserved_space_start = buffer_start;
       joinable_token->before.preserved_space_start = buffer_start;
@@ -2387,10 +2388,11 @@ class TokenPartitionsLayoutOptimizerTest : public ::testing::Test,
                                            public UnwrappedLineMemoryHandler {
  public:
   TokenPartitionsLayoutOptimizerTest()
-      : sample_(
+      : sample_backing_(
             //   :    |10  :    |20  :    |30  :    |40
             "one two three four\n"
             "eleven twelve thirteen fourteen\n"),
+        sample_(sample_backing_),
         tokens_(
             absl::StrSplit(sample_, absl::ByAnyChar(" \n"), absl::SkipEmpty())),
         style_(CreateStyle()),
@@ -2399,7 +2401,7 @@ class TokenPartitionsLayoutOptimizerTest : public ::testing::Test,
       ftokens_.emplace_back(1, token);
     }
     CreateTokenInfosExternalStringBuffer(ftokens_);
-    ConnectPreFormatTokensPreservedSpaceStarts(sample_.data(),
+    ConnectPreFormatTokensPreservedSpaceStarts(sample_.begin(),
                                                &pre_format_tokens_);
 
     // Set token properties
@@ -2423,7 +2425,8 @@ class TokenPartitionsLayoutOptimizerTest : public ::testing::Test,
   }
 
  protected:
-  const std::string sample_;
+  const std::string sample_backing_;
+  const absl::string_view sample_;
   const std::vector<absl::string_view> tokens_;
   std::vector<TokenInfo> ftokens_;
   const BasicFormatStyle style_;

verible/common/formatting/layout-optimizer_test.cc

@@ -56,8 +56,10 @@ class UnwrappedLineMemoryHandler {
   // Points to the end of joined_token_text_ string buffer.
   // Same concept as TextStructureView::EOFToken().
   TokenInfo EOFToken() const {
-    const absl::string_view s(joined_token_text_);
-    return TokenInfo(verible::TK_EOF, absl::string_view(s.end(), 0));
+    return TokenInfo(
+        verible::TK_EOF,
+        absl::string_view(  // NOLINT  might be easier with c++20
+            joined_token_text_.data() + joined_token_text_.length(), 0));
   }
 
  protected:

verible/common/formatting/unwrapped-line-test-utils.h

@@ -23,10 +23,12 @@
 
 namespace verible {
 
-absl::string_view make_string_view_range(const char *begin, const char *end) {
+absl::string_view make_string_view_range(
+    absl::string_view::const_iterator begin,
+    absl::string_view::const_iterator end) {
   const int length = std::distance(begin, end);
   CHECK_GE(length, 0) << "Malformed string bounds.";
-  return absl::string_view(begin, length);
+  return absl::string_view(&*begin, length);
 }
 
 std::pair<int, int> SubstringOffsets(absl::string_view substring,