abidiff: improve whitespace generation in symbol diff report

maybe_report_diff_for_symbol() has a few issues:

1. The responsibility for newline emission is somewhat unclear and
   indeed it would emit spurious blank lines before most of the
   sub-diffs it reports.

2. Different sub-diff text and terminal commas are emitted according to
   whether or not there had been a previous sub-diff - making the output
   harder to grep and post-process.

3. The function also returns a bool but that return value is never used.

Hence, change the function to return void, the function stanzas to
always emit newline-terminated lines and ensure the wording and
punctuation of each sub-diff do not vary. This also tweaks (shortens)
the wording used for CRC diffs.

	* src/abg-reporter-priv.cc (maybe_report_diff_for_symbol):
	Make return void. Simplify and fix new-line emission. Remove
	comma emission. Tweak CRC wording.
	* src/abg-reporter-priv.h (maybe_report_diff_for_symbol):
	Return void.
	* tests/data/test-abidiff-exit/test-crc-report.txt: Shorten CRC
	wording.
	* tests/data/test-abidiff/test-crc-report.txt: Likewise.
	* tests/data/test-diff-filter/test-PR27569-report-0.txt:
	Likewise.

Reviewed-by: Giuliano Procida <gprocida@google.com>
Signed-off-by: Matthias Maennich <maennich@google.com>

5 files changed, 25 insertions, 77 deletions

diff --git a/src/abg-reporter-priv.cc b/src/abg-reporter-priv.cc
index 3091f6ca..7012f5dc 100644
--- a/src/abg-reporter-priv.cc
+++ b/src/abg-reporter-priv.cc
@@ -1081,20 +1081,15 @@ maybe_report_diff_for_member(const decl_base_sptr&	decl1,
 /// @param the output stream to emit the report to.
 ///
 /// @param indent the indentation string to use.
-///
-/// @return true if a report was emitted to the output stream @p out,
-/// false otherwise.
-bool
+void
 maybe_report_diff_for_symbol(const elf_symbol_sptr&     symbol1,
                              const elf_symbol_sptr&     symbol2,
                              const diff_context_sptr&   ctxt,
                              ostream&                   out,
                              const string&              indent)
 {
-  bool reported = false;
-
   if (!symbol1 || !symbol2 || symbol1 == symbol2)
-    return reported;
+    return;
 
   if (symbol1->get_size() != symbol2->get_size())
     {
@@ -1104,108 +1099,65 @@ maybe_report_diff_for_symbol(const elf_symbol_sptr&	symbol1,
                             symbol2->get_size(),
                             *ctxt, out,
                             /*show_bits_or_bytes=*/false);
-      reported = true;
+      out << "\n";
     }
 
   if (symbol1->get_name() != symbol2->get_name())
     {
-      if (reported)
-        out << ",\n" << indent
-            << "its name ";
-      else
-        out << "\n" << indent << "name of symbol ";
-
-      out << "changed from "
+      out << indent << "symbol name changed from "
           << symbol1->get_name()
           << " to "
-          << symbol2->get_name();
-
-      reported = true;
+          << symbol2->get_name()
+          << "\n";
     }
 
   if (symbol1->get_type() != symbol2->get_type())
     {
-      if (reported)
-        out << ",\n" << indent
-            << "its type ";
-      else
-        out << "\n" << indent << "type of symbol ";
-
-      out << "changed from '"
+      out << indent << "symbol type changed from '"
           << symbol1->get_type()
           << "' to '"
           << symbol2->get_type()
-          << "'";
-
-      reported = true;
+          << "'\n";
     }
 
   if (symbol1->is_public() != symbol2->is_public())
     {
-      if (reported)
-        out << ",\n" << indent
-            << "it became ";
-        else
-          out << "\n" << indent << "symbol became ";
-
+      out << indent << "symbol became ";
       if (symbol2->is_public())
         out << "exported";
       else
         out << "non-exported";
-
-      reported = true;
+      out << "\n";
     }
 
   if (symbol1->is_defined() != symbol2->is_defined())
     {
-      if (reported)
-        out << ",\n" << indent
-            << "it became ";
-      else
-        out << "\n" << indent << "symbol became ";
-
+      out << indent << "symbol became ";
       if (symbol2->is_defined())
         out << "defined";
       else
         out << "undefined";
-
-      reported = true;
+      out << "\n";
     }
 
   if (symbol1->get_version() != symbol2->get_version())
     {
-      if (reported)
-        out << ",\n" << indent
-            << "its version changed from ";
-      else
-        out << "\n" << indent << "symbol version changed from ";
-
-      out << symbol1->get_version().str()
+      out << indent << "symbol version changed from "
+          << symbol1->get_version().str()
           << " to "
-          << symbol2->get_version().str();
-
-      reported = true;
+          << symbol2->get_version().str()
+          << "\n";
     }
 
   if (symbol1->get_crc() != 0 && symbol2->get_crc() != 0
       && symbol1->get_crc() != symbol2->get_crc())
     {
-      if (reported)
-        out << ",\n" << indent << "its CRC (modversions) changed from ";
-      else
-        out << "\n" << indent << "CRC value (modversions) changed from ";
-
-      out << std::showbase << std::hex
+      out << indent << "CRC (modversions) changed from "
+          << std::showbase << std::hex
           << symbol1->get_crc() << " to " << symbol2->get_crc()
-          << std::noshowbase << std::dec;
-
-      reported = true;
+          << std::noshowbase << std::dec
+          << "\n";
     }
-
-  if (reported)
-    out << "\n";
-
-  return reported;
 }
 
 /// For a given symbol, emit a string made of its name and version.
diff --git a/src/abg-reporter-priv.h b/src/abg-reporter-priv.h
index 65786a0f..a7c4878c 100644
--- a/src/abg-reporter-priv.h
+++ b/src/abg-reporter-priv.h
@@ -206,7 +206,7 @@ maybe_report_diff_for_member(const decl_base_sptr&	decl1,
                              ostream&                   out,
                              const string&              indent);
 
-bool
+void
 maybe_report_diff_for_symbol(const elf_symbol_sptr&     symbol1,
                              const elf_symbol_sptr&     symbol2,
                              const diff_context_sptr&   ctxt,
diff --git a/tests/data/test-abidiff-exit/test-crc-report.txt b/tests/data/test-abidiff-exit/test-crc-report.txt
index ddba41f4..2dbfa555 100644
--- a/tests/data/test-abidiff-exit/test-crc-report.txt
+++ b/tests/data/test-abidiff-exit/test-crc-report.txt
@@ -4,12 +4,10 @@ Variables changes summary: 0 Removed, 1 Changed, 0 Added variable
 1 function with some indirect sub-type change:
 
   [C] 'function void func1(E)' has some indirect sub-type changes:
-
-    CRC value (modversions) changed from 0x10000001 to 0x10000002
+    CRC (modversions) changed from 0x10000001 to 0x10000002
 
 1 Changed variable:
 
   [C] 'int var1' was changed:
-
-    CRC value (modversions) changed from 0x30000001 to 0x30000002
+    CRC (modversions) changed from 0x30000001 to 0x30000002
 
diff --git a/tests/data/test-abidiff/test-crc-report.txt b/tests/data/test-abidiff/test-crc-report.txt
index 4572a207..9bea309e 100644
--- a/tests/data/test-abidiff/test-crc-report.txt
+++ b/tests/data/test-abidiff/test-crc-report.txt
@@ -4,6 +4,5 @@ Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
 1 function with some indirect sub-type change:
 
   [C] 'function void exported_function()' has some indirect sub-type changes:
-
-    CRC value (modversions) changed from 0xe52d5bcf to 0xe52d5bd0
+    CRC (modversions) changed from 0xe52d5bcf to 0xe52d5bd0
 
diff --git a/tests/data/test-diff-filter/test-PR27569-report-0.txt b/tests/data/test-diff-filter/test-PR27569-report-0.txt
index 419c9fd4..99febd66 100644
--- a/tests/data/test-diff-filter/test-PR27569-report-0.txt
+++ b/tests/data/test-diff-filter/test-PR27569-report-0.txt
@@ -4,7 +4,6 @@ Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
 1 function with some indirect sub-type change:
 
   [C] 'function void device_add_disk(gendisk*)' at genhd.h:420:1 has some indirect sub-type changes:
-
-    CRC value (modversions) changed from 0x8afa957c to 0xa3bc03c
+    CRC (modversions) changed from 0x8afa957c to 0xa3bc03c
     parameter 2 of type 'int' was added